Maxon GPTLR SERIES (2004 Release) Maintenance Manual

M-04-04

JULY 2004

MAINTENANCE MANUAL

GPT-25 & GPT-33

11921 Slauson Ave.

Santa Fe Springs, CA. 90670

LIFT CORP.

CUSTOMER SERVICE:

TELEPHONE (562) 464-0099 TOLL FREE (800) 227-4116

FAX: (888) 771-7713

NOTE: For latest version of all Manuals (and replacements), download the

Manuals from Maxon’s website at www.maxonlift.com.

WARRANTY/ RMA POLICY & PROCEDURE

LIFTGATE WARRANTY

Type of Warranty: Full Parts and Labor

Term of Warranty: Standard Liftgates - 2 years from ship date or 6,000 cycles

Premium Liftgates - 2 years from ship date or 10,000 cycles

This warranty shall not apply unless the product is installed, operated and maintained in accordance with MAXON Lift’s specifications as set forth in MAXON Lift’s Installation, Operation and Maintenance manuals. This warranty does not cover normal wear, maintenance or adjustments, damage or malfunction caused by improper handling, installation, abuse, misuse, negligence, or carelessness of operation. In addition, this warranty does not cover equipment that has had unauthorized modifications or alterations made to the product.

MAXON agrees to replace any components which are found to be defective during the first 2 years of service, and will reimburse for labor based on MAXON’s Liftgate Warranty Flat Rate Schedule. (Copy of the Flat Rate is available at www.maxonlift.com.)

All warranty repairs must be performed by an authorized MAXON warranty facility. For any repairs that may exceed $500, including parts and labor, MAXON’s Technical Service Department must be notified and an “Authorization Number” obtained.

All claims for warranty must be received within 30 Days of the repair date, and include the following information:

1. Liftgate Model Number and Serial Number

2. The End User must be referenced on the claim

3. Detailed Description of Problem

4. Corrective Action Taken, and Date of Repair

5. Parts used for Repair, Including MAXON Part Number(s)

6. MAXON R.M.A. # and/or Authorization # if applicable (see below)

7. Person contacted at MAXON if applicable

8. Claim must show detailed information I.e. Labor rate and hours of work performed

Warranty claims can also be placed on-line at www.maxonlift.com. On-line claims will be given priority processing.

All claims for warranty will be denied if paperwork has not been received or claim submitted via Maxon website for processing by MAXON’s

Warranty Department within 30 days of repair date.

All components may be subject to return for inspection, prior to the claim being processed. MAXON products may not be returned without prior written approval from MAXON’s Technical Service Department. Returns must be accompanied by a copy of the original invoice or reference with original invoice number and are subject to a credit deduction to cover handling charges and any necessary reconditioning costs. Unauthorized returns will be refused and will become the responsibility of the returnee.

Any goods being returned to MAXON Lift must be pre-approved for return, and have the R.M.A. number written on the outside of the package in plain view, and returned freight prepaid. All returns are subject to a 15% handling charge if not accompanied by a detailed packing list. Returned parts are subject to no credit and returned back to the customer.

Defective Parts requested for return must be returned within 30 days of the claim date for consideration to:

MAXON Lift Corp.

16205 Distribution Way, Cerritos, CA 90703

Attn: RMA#__

MAXON’s warranty policy does not include the reimbursement for travel time, towing, vehicle rental, service calls, oil, batteries or loss of income due to downtime. Fabrication or use of non Maxon parts, which are available from MAXON, are also not covered.

MAXON’s Flat Rate Labor Schedule takes into consideration the time required for diagnosis of a problem.

All Liftgates returned are subject to inspection and a 15% restocking fee. Any returned Liftgates or components that have been installed or not returned in new condition will be subject to an additional reworking charge which will be based upon the labor and material cost required to return the Liftgate or component to new condition.

PURCHASE PART WARRANTY

Term of Warranty: 1 Year from Date of Purchase.

Type of Warranty: Part replacement only

MAXON will guarantee all returned genuine MAXON replacement parts upon receipt and inspection of parts and original invoice.

All warranty replacements parts will be sent out via ground freight. If a Rush Shipment is requested all freight charges will be billed to the requesting party.

TABLE OF CONTENTS

WARNINGS ......................................................................................................................... 5

LIFTGATE TERMINOLOGY ................................................................................................... 6

PERIODIC MAINTENANCE ................................................................................................ 8

PERIODIC MAINTENANCE CHECKLIST ............................................................................. 8

CHECKING HYDRAULIC FLUID ......................................................................................... 10

CHANGING HYDRAULIC FLUID ......................................................................................... 12

REPLACING PLATFORM TORSION SPRING .................................................................... 14

PARTS BREAKDOWN ...................................................................................................... 15

GPT MAIN ASSEMBLY ....................................................................................................... 16

MAIN FRAME, LIFTING ARMS, & PARALLEL ARMS GPT 25 & GPT-33 ............................ 18

PLATFORM & FLIPOVER ASSEMBLY ............................................................................... 20

PLATFORM ASSEMBLY .................................................................................................... 21

PUMP COVER & MOUNTING PLATE ASSEMBLY ............................................................. 23

GRAVITY DOWN HYDRAULIC COMPONENTS .................................................................. 24

12 VDC POWER UNIT (GRAVITY DOWN) .......................................................................... 25

POWER DOWN HYDRAULIC COMPONENTS ................................................................... 26

12 VDC POWER UNIT (POWER DOWN) ........................................................................... 27

DECALS ............................................................................................................................ 28

CONTROL SWITCH AND POWER CABLE ........................................................................ 30

HYDRAULIC SYSTEM DIAGRAMS .................................................................................. 31

HYDRAULIC SCHEMATIC (GRAVITY DOWN) .................................................................... 31

HYDRAULIC SCHEMATIC (POWER DOWN) ..................................................................... 32

ELECTRICAL SYSTEM DIAGRAMS ................................................................................ 33

ELECTRICAL SCHEMATIC (GRAVITY DOWN) .................................................................. 33

ELECTRICAL SCHEMATIC (POWER DOWN) ................................................................... 34

RECOMMENDED BOLT TORQUES ................................................................................. 35

TROUBLESHOOTING ...................................................................................................... 36

PLATFORM WILL NOT RAISE ............................................................................................ 36

PLATFORM RAISES BUT LEAKS DOWN .......................................................................... 37

PLATFORM RAISES PARTIALLY AND STOPS .................................................................. 38

LIFTGATE WILL NOT LIFT RATED CAPACITY ................................................................... 39

PLATFORM RAISES SLOWLY ........................................................................................... 40

PLATFORM WILL NOT LOWER, LOWERS TOO SLOWLY, OR LOWERS TOO QUICKLY .. 41

Comply with the following WARNINGS while maintaining Liftgates. See Operation Manual

M-04-05 for operating safety requirements.

!!!!!

WARNING

S

• Read and understand the instructions in this Maintenance Manual before performing maintenance on the Liftgate.

• Before operating the Liftgate, read and understand the operating instructions in Operation Manual

M-04-05.

• Comply with all WARNING and instruction decals attached to the Liftgate.

• Keep decals clean and legible. If decals are defaced or missing, replace them. Free replacement decals are available from Maxon Parts Department.

• Consider the safety and location of bystanders and location of nearby objects when operating the

Liftgate. Stand to one side of the platform while operating the Liftgate

• Do not allow untrained persons to operate the Liftgate.

• Do not stand under, or allow obstructions under the platform when lowering the Liftgate. Be sure your feet are clear of the Liftgate.

• Keep fingers, hands, arms, legs, and feet clear of moving Liftgate parts (and platform edges) when operating the Liftgate.

• Correctly stow platform when not in use. Extended platforms could create a hazard for people and vehicles passing by.

• Disconnect Liftgate power cable from battery before repairing or servicing Liftgate.

• Wear apppropriate safety equipment such as protective eyeglasses, faceshield and clothing while performing maintenance on the Liftgate and handling the battery. Debris from drilling and contact with battery acid may injure unprotected eyes and skin.

• Be careful working by an automotive type battery. Make sure the work area is well ventilated and there are no flames or sparks near the battery. Never lay objects on the battery that can short the terminals together. If battery acid gets in your eyes, immediately seek first aid. If acid gets on your skin, immediately wash it off with soap and water.

• If an emergency situation arises (vehicle or Liftgate) while operating the Liftgate, release the control

Toggle Switch and the Liftgate will stop.

• A correctly installed Liftgate operates smoothly and reasonably quiet. The only noticeable noise during operation comes from the pump unit while the platform is raised. Listen for scraping, grating and binding noises and correct the problem before continuing to operate Liftgate.

• If it is necessary to stand on the platform while maintaining the Liftgate, keep your feet and any objects clear of the inboard edge of the platform. Your feet or objects on the platform could be trapped between the platform and the Liftgate extension plate.

• Never perform unauthorized modifications on the Liftgate. Modifications may result in early failure of the Liftgate and may create hazards for Liftgate operators and maintainers.

• Use only Maxon Authorized Parts for replacement parts. Provide Liftgate model and serial number information with your parts order. Order replacement parts from:

MAXON LIFT CORP. Customer Service

11921 Slauson Ave., Santa Fe Springs, CA 90670

Phone: (800) 227-4116

• To order parts by e-mail, submit orders to [email protected].

5

LIFTGATE TERMINOLOGY

EXTENSION

PLATE

LIFT

CYLINDER

PARALLEL

ARM

PLATFORM

CONTROL

SWITCH

PLATFORM

OPENER

MAIN

FRAME

LIFT

ARM

FLIPOVER WITH

FIXED RAMP

PUMP

BOX

SAFETY

HOOK

6

THIS PAGE INTENTIONALLY LEFT BLANK

7

PERIODIC MAINTENANCE

PERIODIC MAINTENANCE CHECKLIST

!!!!!

WARNING

Never operate the Liftgate with parts loose or missing.

NOTE: Make sure Vehicle is parked on level ground while performing the maintenance checks.

Annually or 5000 Cycles (whichever occurs first)

Visually check the entire Liftgate for excessively worn parts and broken welds, especially Hinge Pins. See

PARTS BREAKDOWN section for replacement parts.

Check the Platform and Flipover as follows. With

Platform open at Bed Height (Vehicle Body), check the outboard edge of Flipover. The outboard edge must be just above level line as shown in FIG. 8-1. If outboard edge of Flipover is below the level line, check pins and bearings at the pivot points on both sides of the Liftgate

(see FIG. 8-2). See PARTS BREAKDOWN section for replacement parts.

LIFT

CYLINDER

OUTBOARD

EDGE

LEVEL LINE

PLATFORM EDGE ABOVE

BED LEVEL

FIG. 8-1

LIFT ARM

PARALLEL

ARM

PLATFORM

To prevent unnecessary wear on

Parallel Arms, check for worn flanged bearings as follows. Position the Platform 1”-2” above ground (FIG. 9-1A).

Push against the Shackle (FIG. 9-1B,

item 1) and measure clearance (FIG.

9-1B, item 1). Then push against other side of Shackle (FIG. 9-1B, item 2) and measure clearance (FIG. 9-1B,

item 2). Repeat for LH side Shackle. If clearance is less than 0.060”, replace flanged bearing. See PARTS BREAK-

DOWN section for replacement parts.

PIVOT POINTS

(PINS & BEARINGS)

PIVOT POINTS TO CHECK

FIG. 8-2

Also, do the Semi-annual or 2500 Cycles and Quarterly or 1250 Cycles checks.

8

BEARING FLANGES

PARALLEL

ARM

SHACKLE

0.060”

0.060” 1”-2”

CHECKING SHACKLE

CLEARANCES (RH SIDE SHOWN)

FIG. 9-1B

PLATFORM AT GROUND LEVEL

FIG. 9-1A

Semi-annually or 2500 Cycles (whichever occurs first)

Visually check the Platform Hinge Pins for excessive wear and broken welds. See PARTS

BREAKDOWN section for replacement parts. Also, do the Quarterly or 1250 Cycles maintenance checks.

Quarterly or 1250 Cycles (whichever occurs first)

Check the Hydraulic Fluid level in the Pump Reservoir. Refer to the CHECKING HYDRAULIC

FLUID procedure in the PERIODIC MAINTENANCE section.

If Hydraulic Fluid appears contaminated, refer to the CHANGING HYDRAULIC FLUID procedure in the PERIODIC MAINTENANCE section.

Keep track of the grade of Hydraulic Fluid in the Pump Reservoir and never mix two different grades of fluid.

Check all Hoses and Fittings for chaffing and fluid leaks. Replace if necessary.

Check electrical wiring for chaffing and make sure wiring connections are tight and free of corrosion.

Check that all WARNING and instruction decals are in place and legible.

Check that all roll pins are in place and protrude evenly from both sides of Hinge Pin collar.

Replace roll pins if necessary.

Check for rust and oily surfaces on Liftgate. If there is rust or oil on Liftgate, clean it off. Touch up the paint where bare metal is showing.

9


CHECKING HYDRAULIC FLUID

CAUTION

Keep dirt, water and other contaminants from entering the hydraulic system.

Before opening the hydraulic fluid reservoir filler cap, drain plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination.

NOTE: Use correct grade of hydraulic fluid for your location.

+70 to +140 Degrees F - Grade ISO 32


Below + 70 Degrees F - Grade ISO 10 or MIL-H-5606

See TABLES 9-1, 9-2 & 9-3 on the next page for recommended brands.

1. Unbolt & remove Pump Cover (FIG. 8-2).

FILLER

CAP

NOTE: If the Hydraulic Fluid in the

Reservoir is contaminated, do the CHANGING HYDRAULIC

FLUID procedure in this section.

2. Check the Hydraulic Fluid level in Reservoir.

With Liftgate stowed or Platform at Vehicle bed height, Level should be 3” (FIG. 10-1).

If needed, add fluid to the Reservoir as follows.

RESERVOIR

3”

POWER UNIT FLUID LEVEL

FIG. 10-1

3. Pull out (no threads) Filler Cap (FIG. 10-1).

Fill the Reservoir with Hydraulic Fluid to level shown in FIG. 10-1. Reinstall Filler

Cap (FIG. 10-1)

NUTS

CAUTION

Pump Cover must be correctly secured to prevent it from becoming a hazard. To secure Pump

Cover, the long side of the Holder

Flats must be installed as shown in the illustration.

4. Bolt on the Pump Cover as shown in FIG. 10-2.

Torque the 5/16”-18 cover bolts 20 to 29 LBS.-

FT.

FLAT

WASHERS

POWER UNIT

(REF)

PUMP COVER

LONG SIDE OF

HOLDER FLATS

PUMP COVER

CAP

SCREWS

UNBOLTING / BOLTING PUMP COVER

FIG. 10-2

10

I S O 3 2 H Y D R A U L I C O I L

R E C O M M E N D E D B R A N D S

A M S O I L

C H E V R O N

K E N D A L L

S H E L L

E X X O N

M O B I L

P A R T N U M B E R

A W H 0 5

H I P E R S Y N 3 2

G O L D E N M V

T E L L U S T 3 2

U N I V I S N 3 2

D T E

H Y D

1 3

R A

M ,

U L I

D T E 2 4 ,

C O I L 1 3

TABLE 11-1

I S O 1 5 H Y D R A U L I C O I L


A M S O I L

C H E V R O N

K E N D A L L

S H E L L

E X X O N

M O B I L

P A R T N U M B

A W F 0 5

F L U I D A , A W M V 1 5

G L A C I A L B L U

T E L L U S T 1 5

U N I V I S H V I 1 3

D T E 1 1 M

E R

TABLE 11-2

I S O 1 0 O R M I L H 5 6 0 6 H Y D R A U L I C F L U I D


A M S O I L

C H E V R O N

K E N D A L L

S H E L L

E X X O N

M O B I L

P A R T N U M B E R

N / A

F L U I D A , F L U I D G

G L A C I A L B L U

A E R O S H E L L F L U I D 4 1

U N I V I S H V I 1 3

A E R O H F A

TABLE 11-3

11


CHANGING HYDRAULIC FLUID

CAUTION

Keep dirt, water and other contaminants from entering the hydraulic system.

Before opening the hydraulic fluid reservoir filler cap, drain plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination.

NOTE: Use correct grade of hydraulic fluid for your location.



Below + 70 Degrees F - Grade ISO 10 or MIL-H-5606

See TABLES 9-1, 9-2 & 9-3 on previous page for recommended brands.

GRAVITY DOWN LIFTGATES

1 . Remove the Pump Cover (FIG. 12-2). Place empty

5 Gallon Bucket under Drain Plug (FIG. 12-1).

FILLER

CAP

RESERVOIR

2. Lower Platform to ground. Pull out (no threads)

Drain Plug (FIG. 12-1). Drain hydraulic fluid from system. Reinstall Drain Plug.

5-1/2”

3. Pull out (no threads) Filler Cap (FIG. 12-1) and refill reservoir with Hydraulic Fluid to level shown in

FIG. 12-1. Reinstall Filler Cap (FIG. 12-1).

DRAIN PLUG

GRAVITY DOWN PUMP & MOTOR

FIG. 12-1

POWER UNIT

(REF)

CAUTION




NUTS

PUMP COVER

LONG SIDE OF

HOLDER FLATS

FLAT

WASHERS


Torque the 5/16”-18 cover bolts Torque the

5/16”-18 cover bolts 20 to 29 LBS.-FT.

PUMP COVER

CAP

SCREWS

UNBOLTING / BOLTING PUMP COVER

FIG. 12-2

12

POWER DOWN LIFTGATES

1. Remove the Pump Cover (FIG. 10-2). Place empty

5 Gallon Bucket under Drain Plug (FIG. 10-1).

2. Open and raise Platform to vehicle bed height.

Pull out (no threads) Drain Plug (FIG. 10-1).

Drain hydraulic fluid.

3. Disconnect the Motor Power Cable (FIG. 13-1) from bottom Starter Solenoid. Lower the Platform while draining the remaining hydraulic fluid from system. Reinstall Drain Plug. Reconnect the

Motor Power Cable to bottom Starter Solenoid.

Torque hex nut to 95 LBS.-IN.

BOTTOM

STARTER

SOLENOID

HEX NUT

MOTOR POWER

CABLE

POWER DOWN PUMP

FIG. 13-1

4. Pull out (no threads) Filler Cap (FIG. 10-1) and refill reservoir with Hydraulic Fluid to level shown in FIG. 10-1. Reinstall Filler Cap (FIG. 10-1).

CAUTION





Torque the 5/16”-18 cover bolts Torque the 5/16”-

18 cover bolts 20 to 29 LBS.-FT.

13


REPLACING PLATFORM TORSION SPRING

NOTE: The following procedure shows how to replace Torsion Spring on RH side of

Platform. Use this procedure for replacing Torsion Spring on the LH Side.

1. Fold Flipover onto Platform.

2. Fold Platform.

SPRING

BRACKET

BOLT

HINGE

BRACKET

BOLT

3. Raise Liftgate to a convenient work height to gain access and release tension on the

Torsion Spring.

!!!!!

CAUTION

To prevent injury and equipment damage, make sure there is no tension on torsion spring before removing hinge pin.

WASHER

LOCK NUT

WASHER

SHACKLE

FIG. 14-1

4. Unbolt Hinge Pin from Shackle and Spring

Bracket (FIG. 14-1). Remove bolts, washers, and lock nuts. Drive the Hinge Pin outboard toward the Shackle just enough to free the torsion spring (FIG. 14-2). Remove the

Torsion Spring.

TORSION

SPRING

HINGE

PIN

5. Install the Torsion Spring as shown in FIG.

14-3. Make sure the long leg of the spring is inserted in the Spring Bracket (FIG. 14-3).

Make sure the short end of the spring is visible and resting against the Hinge Bracket

(FIG. 14-3).

SHACKLE

FIG. 14-2

6. Drive the Hinge Pin into correct position through the Hinge Bracket as shown in

FIG. 14-3. Line up the bolt hole in the

Hinge Pin with the hole in the Shackle and Spring Bracket. Bolt the Hinge Pin to

Hinge Bracket and Spring Bracket with bolts, washers, lock nuts (FIG. 14-

2).Torque the 3/8”-16 Spring Pin bolt and

3/8”-16 Spring Bracket bolt 35 to 52

LBS.-FT.

7. Operate the Liftgate according to instructions in Operation Manual to make sure it operates correctly.

SPRING

BRACKET

LONG

LEG

BOLT

SHORT

CHAMFERED

LEG

HINGE

BRACKET

BOLT

WASHER

LOCK NUT

WASHER

SHACKLE

FIG. 14-3

14

PARTS BREAKDOWN

15

GPT MAIN ASSEMBLY

1A

1

REFER TO PUMP

COVER, HYDRAULIC

COMPONENTS, &

POWER UNITS

1B

REFER TO MAIN FRAME, LIFT-

ING ARMS & PARALLEL ARMS

4

7

2

REFER TO PLATFORM &

FLIPOVER ASSEMBLY

9

2

5A

6

3

5

7

3

2

2

4

6

5A

8

8

9

6

7

5 A

2

3

4

1 A

1 B

5

I T E M Q T Y .

1 1

4

2

6

1

2

1

2

1

2

2

1

P A R T N O .

2 8 1 0 9 0 0 1

2 8 1 0 9 0 0 2

2 0 7 6 4 4

0 5 0 1 7 5

9 0 2 0 0 0 1 4

9 0 0 0 3 5 3

9 0 1 0 1 0

2 8 0 9 9 8 0 1

2 8 0 9 9 8 0 2

9 0 8 0 0 8 0 1

9 0 2 0 1 3 2 1

2 2 1 4 1 6

2 2 6 9 3 8

2 2 7 7 0 0

D E S C R I P T I O N

E X T E N S I O N P L A T E A S S E M B L Y , 9 6 " L G .

E X T E N S I O N P L A T E A S S E M B L Y , 1 0 2 " L G .

R I V E T

M A X O N P L A T E

F L A T W A S H E R , 1 / 2 "

C A P S C R E W 1 / 2 " 1 3 X 1 1 / 2 " L .

G .

L O C K N U T , 1 / 2 " 1 3

U N D E R R I D E , 9 6 "

U N D E R R I D E , 1 0 2 "

B E A R I N G

F L A T W A S H E R , 1 3 / 8 "

R O L L P I N

E Y E , D R O P F O R G E D P A D 3 / 4 " X 1 1 / 2 "

H O O K A S S E M B L Y

16


17

MAIN FRAME, LIFTING ARMS, & PARALLEL ARMS

GPT 25 & GPT-33

29

28

30

30

4 3

5

31

30

29

3

3

7

6

8A 1

8A

2

31

2

30

5

7

9

8

6

11B

8B

19

17 20

21

8A

22

7

15D

15C

15A

11A

23

7

15

15B

17

18

16

17

19

POSITION #2 FOR

44”- 49” BED HEIGHT

24

14

11

15B

15 8B

8

8A

9

7

13

25

16

17

19

12

15A

15C

15D

23

8A

26

17

27

7

21

19

12

13

17

20

14

10A

8A

4

10

7

7

10B

POSITION #1 FOR

49”- 53” BED HEIGHT

18

4

5

2

3

6

2 5

2 6

2 7

2 8

2 9

2 1

2 2

2 3

2 4

3 0

3 1

1 5

1 5 A

1 5 B

1 5 C

1 8

1 9

2 0

1 5 D

1 6

1 7

7

8

8 A

8 B

9

1 0

1 0 A

1 0 B

1 1

1 2

1 3

1 4

1 1 A

1 1 B

2

2

2

8

2

2

1

2

1

1

1

4

2

6

1

4

8

1

2

4

2

2

2

2

2

2

2

2

2

1 2

2

1

1

1

1

1

2

1

8

2

MAIN FRAME, LIFTING ARMS, & PARALLEL ARMS

GPT 25 & GPT-33

I T E M Q T Y .

1 1

P A R T N O .

2 8 0 9 1 0 0 1

2 8 0 9 1 0 0 2

0 4 0 1 0 3 5

2 0 5 7 8 0

2 8 0 9 6 9 0 2

2 8 0 9 6 8 0 1

2 8 1 0 0 5 0 1

9 0 2 0 0 0 1 0

2 8 1 0 0 0 0 2

9 0 1 0 0 2

9 0 0 0 1 4 1 1

2 8 1 0 0 4

2 8 0 9 7 1 0 2

2 8 0 9 7 6 0 1

2 8 0 9 5 0 0 2

2 8 1 0 0 0 0 1

2 8 0 9 5 0 0 1

2 8 1 1 2 7 0 1

9 0 8 0 1 2 0 1

0 3 0 3 3 4

2 8 0 9 1 8 0 1

2 8 0 0 8 2 0 1

9 0 0 0 3 5 8

9 0 2 0 0 0 1 4

9 0 1 0 1 0

9 0 0 0 1 4 9

2 8 0 9 7 1 0 1

2 8 1 1 0 2 0 1

9 0 0 0 3 5 7

9 0 2 0 0 0 1 6

9 0 1 0 1 0

2 2 1 4 1 6

2 8 0 9 1 2 0 1

9 0 8 0 3 7

9 0 8 0 2 4 0 1

9 0 2 0 1 3 2 1

2 8 0 9 1 5 0 1

9 0 8 0 2 3 0 1

9 0 8 0 2 3 0 2

2 8 0 9 1 5 0 2

9 0 8 0 2 3 0 1

9 0 8 0 2 3 0 2


M A I N F R A M E , 9 6 " W I D E

M A I N F R A M E , 1 0 2 " W I D E

S P L I T L O O M

P L A S T I C T I E S

P I N , 1 3 / 8 " D I A X 6 " L G .

P I N , 1 3 / 8 " D I A X 5 7 / 8 " L G .

P I N , 7 " L G .

R O L L P I N

P A R A L L E L A R M S

B E A R I N G

B E A R I N G

F L A T W A S H E R , 1 3 / 8 "

L I F T A R M , R H

B E A R I N G

B E A R I N G

L I F T A R M , L H

B E A R I N G

B E A R I N G

P I N , C Y L I N D E R

C A M F O L L O W E R

L O C K N U T , 5 / 8 " 1 8

O P E N E R

R O L L E R

C A P S C R E W , 1 / 2 " 1 3 X 2 3 / 4 " L G .

F L A T W A S H E R , 1 / 2 "

L O C K N U T , 1 / 2 " 1 3

C A P S C R E W , 3 / 8 " 1 6 X 2 1 / 4 " L G .

F L A T W A S H E R , 3 / 8 "

B R A C K E T , L H

L O C K N U T , 3 / 8 " 1 6

C A P S C R E W , 3 / 8 " 1 6 X 3 " L G .

P I N , S P R I N G

S H A C K L E , L H

P I N , 5 5 / 8 " L G .

T O R S I O N S P R I N G , L H

B R A C K E T , R H

T O R S I O N S P R I N G , R H

S H A C K L E , R H

S A D D L E

C A P S C R E W 1 / 2 " 1 3 X 2 1 / 2 " L G .

F L A T W A S H E R , 9 / 1 6 "

L O C K N U T , 1 / 2 " 1 3

19

PLATFORM & FLIPOVER ASSEMBLY

REFER TO

PLATFORM

ASSEMBLY

1B

1C

4

5

5

2

3

2

1A

2

1

I T E M

1

Q T Y .

1

1 A

2

3

4

5

1 B

1 C

1

2

1 0

4

4

1 5

2

1B

1C (10 PLACES)

P A R T N O .

2 8 0 9 9 9 0 1

2 8 0 9 9 9 0 2

2 8 0 9 9 5 0 1

2 8 0 9 9 5 0 2

2 8 0 9 4 1 0 1

9 0 0 7 0 5 0 1

2 8 1 0 1 0 0 1

2 6 3 4 5 6 1 3

9 0 5 0 1 5 1

9 0 2 0 0 0 1 4


F L I P O V E R A S S E M B L Y , 7 9 1 / 2 " L G .

F L I P O V E R A S S E M B L Y , 8 5 1 / 2 " L G .

F L I P O V E R W E L D M E N T , 7 9 " L G .

F L I P O V E R W E L D M E N T , 8 5 " L G .

S I D E P L A T E , F L I P O V E R

S E L F T A P P I N G S C R E W , 1 / 4 " 2 0 X 1 " L G .

H I N G E A S S E M B L Y

H I N G E , R O D

R O L L P I N

F L A T W A S H E R , 1 / 2 "

20

5

5 4

12

13

PLATFORM ASSEMBLY

5

8

6

7

3

4

3

9

10

5

1

11

I T E M Q T Y .

R E F 1

1

8

9

6

7

4

5

2

3

1 0

1 1

1 2

1 3

1

2

2

6

1

1

6

6

1

1

6

6

1 0

P A R T N O .

2 8 1 0 0 0 0 1

2 8 1 0 0 0 0 2

2 8 0 9 9 2 0 1

2 8 0 9 9 2 0 2

2 8 1 0 7 0 0 1

9 0 2 0 1 3 1 1

9 0 1 0 0 2

9 0 0 0 6 4 0 7

2 8 1 0 7 0 0 2

9 0 8 0 2 6 0 1

9 0 8 0 0 8 0 2

9 0 2 0 1 1 6

9 0 0 0 3 5 5

2 8 0 9 8 7 0 1

2 8 0 9 8 7 0 2

9 0 0 7 0 5 0 1

13 (10 PLACES)


P L A T F O R M A S S E M B L Y , 7 9 1 / 2 " L G .

P L A T F O R M A S S E M B L Y , 8 5 1 / 2 " L G .

P L A T F O R M W E L D M E N T , 7 9 " L G .

P L A T F O R M W E L D M E N T , 8 5 " L G .

S U P P O R T , R H

F L A T W A S H E R , 3 / 8 "

L O C K N U T , 3 / 8 " 1 6

B U T T O N H E A D S C R E W , 3 / 8 " 1 6 X 3 " L G .

S U P P O R T , L H

B E A R I N G , 1 3 / 4 " L G .

B E A R I N G , 5 / 8 " L G .

L O C K W A S H E R , 1 / 2 "

C A P S C R E W , 1 / 2 " 1 3 X 2 " L G .

S I D E P L A T E , R H , P L A T F O R M

S I D E P L A T E , L H , P L A T F O R M

S E L F T A P P I N G S C R E W , 1 / 4 " 2 0 X 1 " L G .

21

10

3

2

8

9

3

4

3

7


22

7

PUMP COVER & MOUNTING PLATE ASSEMBLY

8

9

8

10

6

5

11

14

MAIN FRAME

(REF)

4

3

12

2

1

6

5

13

4

3

12

12 VDC POWER UNIT

(REF)

NOTE: LEAVE 1/4” GAP FOR DRAINAGE.

2

2

1

1

1

2

2

2

4

1

Q T Y .

2

2

1

1

1 0

1 1

1 2

8

9

6

7

1 3

1 4

3

4

5

I T E M

1

2

P A R T N O .

2 8 1 0 3 8 0 1

0 9 3 2 0 3 1 0

9 0 0 0 9 8

2 8 1 0 6 2 0 2

9 0 2 0 1 3 1 0

9 0 1 0 0 1

9 0 0 0 6 4 0 3

9 0 2 0 1 1 4

9 0 0 0 6 4 0 4

9 0 3 4 0 0 0 2

2 6 6 4 2 8 0 2

9 0 8 0 2 2 0 1

9 0 8 0 2 2 0 3

2 8 1 0 6 5 0 1


C O V E R A S S Y

G A S K E T , R U B B E R C H A N N E L , 6 0 " L G .

C A P S C R E W , 5 / 1 6 " 1 8 X 2 " L G .

H O L D E R F L A T S

F L A T W A S H E R , 5 / 1 6 "

L O C K N U T , 5 / 1 6 " 1 8

B U T T O N H E A D S C R E W , 3 / 8 " 1 6 X 3 / 4 " L G .

L O C K W A S H E R , 3 / 8 "

B U T T O N H E A D S C R E W , 3 / 8 " 1 6 X 7 / 8 " L G .

L O C K W A S H E R , E X T E R N A L T O O T H

G R O M M E T , 1 / 4 " H O L E

P L U G , F L E X I B L E

P L U G , F L E X I B L E

P L A T E , P U M P M O U N T

23

1A

1

18

2

GRAVITY DOWN HYDRAULIC COMPONENTS

10

RH CYLINDER

SEE 12 VDC POWER UNIT

(GRAVITY DOWN)

LH CYLINDER

1A

1B

3

6

15

16

17

14

17

13

12

17

17

9

19

1B

1

2

18

8

1A

4

5

PUMP

MOUNTING

PLATE (REF)

5

4

1A

11

7

CAUTION

To prevent incorrect operation & damage to liftgate, make sure arrow on flow regulator valve points up as shown in illustration.

Q T Y .

2

1

1

1

1

2

1

1

1

2

1

2

2

2

5

2

1

3

1

1

1

5

6

7

8

2

3

4

I T E M

1

1 A

1 B

1 4

1 5

1 6

1 7

9

1 0

1 1

1 2

1 3

1 8

1 9

P A R T N O .

2 8 0 9 9 0 0 1

9 0 8 0 3 3

2 8 0 9 9 0 S K 0 1

9 0 6 7 0 4 0 1

2 8 1 0 5 7 0 1

2 2 8 0 1 2

2 0 2 4 0 6

2 2 4 3 7 0 2 1

2 2 4 3 7 0 1 8

2 8 1 0 5 7 0 2

2 2 4 3 7 0 2 0

9 0 6 7 4 9 0 1

2 8 1 0 6 7 0 1

9 0 6 7 4 4 0 1

9 0 2 0 2 8 1 2

9 0 6 7 0 8 0 1

9 0 6 7 0 9 0 3

9 0 6 7 4 5 0 1

9 0 6 7 1 2 0 2

9 0 6 7 1 2 0 3

9 0 6 7 2 8 0 1


C Y L I N D E R ( G P T 2 5 / 3 3 )

P O L Y L U B E B E A R I N G

S E A L K I T ( G P T 2 5 / 3 3 C Y L I N D E R )

E L B O W , 9 0 ° F / S , # 8 M M

H O S E A S S Y , 3 / 8 " H P , 4 0 " L G .

A D A P T E R , S T R A I G H T T H R E A D , 9 / 1 6 " 1 8 M 1 / 4 " F

E L B O W , B R A S S 1 / 4 " x 1 / 4 "

H O S E , P L A S T I C 3 8 " L G .

H O S E , P L A S T I C 9 5 " L G .

H O S E A S S Y , 3 / 8 " H P , 1 1 2 " L G .

H O S E , P L A S T I C 9 " L G .

U N I O N T E E

F / S T U B E A S S Y

B U L K H E A D U N I O N

F L A T W A S H E R , 3 / 4 "

E L B O W , 9 0 ° F / S , # 6 M M

F L O W R E G U L A T O R V A L V E , 3 G P M

B R A N C H T E E

O R I N G , # 6 ( 3 / 8 " F A C E S E A L T U B E E N D )


D U A L B A R B E D F I T T I N G

24

12 VDC POWER UNIT (GRAVITY DOWN)

12

CONTROL SWITCH

WIRING HARNESS

(REF)

4

2

10

3

9

13

1

5

11 (VALVE "A")

6

14

7

I T E M Q T Y .

R E F

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1 3

1 4

1 5

9

1 0

1 1

1 2

7

8

5

6

3

4

1

2

P A R T N O .

2 8 1 0 1 5 0 1

2 9 0 0 6 5

2 8 0 5 6 6 0 1

2 8 0 4 0 4

2 8 0 3 9 4

9 0 6 7 0 7

2 8 0 8 0 6 0 1

2 8 1 0 1 3 0 1

9 0 8 0 1 7 0 1

2 8 0 4 1 6

2 9 0 0 6 4

9 0 6 7 1 9 0 1

2 8 0 3 7 4

9 0 6 7 3 7 0 1

9 0 8 0 1 6 0 1

9 0 8 0 1 8 0 1

15

8


1 2 V D C P O W E R U N I T ( G R A V I T Y D O W N )

P O R T P L A T E & P U M P A S S E M B L Y ( G R A V I T Y D O W N )

W I R E A S S E M B L Y 1 6 G A , G R E E N

C A B L E A S S E M B L Y

M O T O R S T A R T E R S O L E N O I D , 1 2 V O L T S D C

9 0 ° E L B O W

F I L L E R C A P

R E S E R V O I R

D R A I N P L U G

W I R E A S S E M B L Y

1 2 V D C C O I L

V A L V E ( V A L V E " A " )

M O T O R , 1 2 V O L T S D C

R E L I E F V A L V E

G R O M M E T , 1 9 / 3 2 "

G R O M M E T , 5 / 1 6 "

25

POWER DOWN HYDRAULIC COMPONENTS

1A

RH CYLINDER

16

13

16

1

1B

12

11

16

2

17

16

15

14

3

15

16

16

1A

4

16

SEE 12 VDC

POWER UNIT

(POWER DOWN)

LH CYLINDER

1A

8

1B

4

16

1

2

17

5

1A

7

9

PUMP

MOUNTING

PLATE (REF)

6

CAUTION

To prevent incorrect operation & damage to liftgate, make sure arrow on flow regulator valve points up as shown in illustration.

Q T Y .

2

1

1

1

1

1 0

2

1

9

1

1

1

1

2

1

2

1

2

2

8

9

6

7

4

5

2

3

I T E M

1

1 A

1 B

1 4

1 5

1 6

1 7

1 0

1 1

1 2

1 3

P A R T N O .

2 8 0 9 9 0 0 1

9 0 8 0 3 3

2 8 0 9 9 0 S K 0 1

9 0 6 7 0 4 0 1

2 8 1 0 5 7 0 1

9 0 6 7 0 7 0 1

2 8 1 0 5 7 0 2

2 8 1 0 5 8 0 2

2 8 1 0 5 8 0 1

2 8 1 0 5 5 0 1

2 8 1 0 5 6 0 1

9 0 6 7 4 4 0 1

9 0 2 0 2 8 1 2

9 0 6 7 4 8 0 1

9 0 6 7 0 8 0 1

9 0 6 7 0 9 0 3

9 0 6 7 4 5 0 1

9 0 6 7 1 2 0 2

9 0 6 7 1 2 0 3


C Y L I N D E R ( G P T 2 5 / 3 3 )

P O L Y L U B E B E A R I N G

S E A L K I T ( G P T 2 5 / 3 3 C Y L I N D E R )

E L B O W , 9 0 ° F / S , # 8 M M

H O S E A S S Y , 3 / 8 " H P , 4 0 " L G .

E L B O W , 9 0 ° F / S , # 6 M M

H O S E A S S Y , 3 / 8 " H P , 1 1 2 " L G .

H O S E A S S Y , 3 / 8 " H P , 9 5 " L G .

H O S E A S S Y , 3 / 8 " H P , 3 8 " L G .



B U L K H E A D U N I O N

F L A T W A S H E R , 3 / 4 "

B U L K H E A D R U N T E E

E L B O W , 9 0 ° F / S , # 6 M M

F L O W R E G U L A T O R V A L V E , 3 G P M

B R A N C H T E E



26

12 VDC POWER UNIT (POWER DOWN)

13

1

16 4

4

6

5

CONTROL SWITCH

WIRING HARNESS

(REF)

2

11

12

7 (VALVE “B”)

3

8

14

7 (VALVE “A”)

9

I T E M

1

1

1

1

1

1

1

1

2

1

2

2

1

2

2

Q T Y .

R E F

1

1 1

1 2

1 3

8

9

1 0

1 4

1 5

1 6

5

6

3

4

7

1

2

P A R T N O .

2 8 1 0 2 0 0 1

2 8 0 3 8 1

2 9 0 0 6 6

9 0 6 7 0 7 0 1

2 8 0 4 0 4

2 8 0 5 4 3

9 0 6 7 2 0 0 1

9 0 6 7 1 9 0 1

2 8 0 8 0 6 0 1

2 8 1 0 1 4 0 1

9 0 8 0 1 7 0 1

9 0 6 7 3 8 0 2

9 0 6 7 3 8 0 1

2 8 0 5 6 6 0 1

9 0 8 0 1 6 0 1

9 0 8 0 1 8 0 1

2 8 0 3 9 4

15

10


1 2 V D C P O W E R U N I T ( P O W E R D O W N )

M O T O R , 1 2 V O L T S D C

P O R T P L A T E & P U M P A S S E M B L Y ( P O W E R D O W N )

E L B O W , 9 0 °



1 0 V D C C O I L

V A L V E

F I L L E R C A P

R E S E R V O I R

D R A I N P L U G

R E L I E F V A L V E , H P

R E L I E F V A L V E , L P

W I R E A S S E M B L Y , 1 6 G A , G R E E N

G R O M M E T , 1 9 / 3 2 "

G R O M M E T , 5 / 1 6 "

M O T O R S T A R T E R S O L E N O I D , 1 2 V O L T S D C

27

DECALS

CAPACITY DECAL

(GPT-25 ONLY)

P/N 220382

CAPACITY DECAL

(GPT-33 ONLY)

P/N 220388-02

CHAIN HOOK DECAL

P/N 263998-01

INSTRUCTION DECAL

P/N 251867-07

FIG. 28-1

28

WARNING DECAL

P/N 264081

CAUTION DECAL

P/N 265736-01

CONTROL SWITCH

DECAL

P/N 264507

CAUTION DECAL

P/N 265736-02

29

CONTROL SWITCH AND POWER CABLE

NOTE: Use Switch to RAISE and LOWER Liftgate to make sure Switch

operates as shown on the decal.

(FOR REFERENCE-

SEE DECALS)

3

I T E M

1

4

5

2

3

6

Q T Y .

1

1

1

1

2

1

SHORT END TO

VEHICLE BATTERY

BLACK

4

YELLOW

WHITE

1

GREEN

2

RED

WHITE

P A R T N O .

2 8 0 6 3 7 0 1

2 8 0 6 3 8 0 1

2 6 4 3 4 6

9 0 0 0 5 7 5

9 0 5 2 0 6

2 6 4 4 2 2

2 6 4 6 8 7

FIG. 30-1


H A R N E S S A S S E M B L Y , 8 4 " L G .

( G R A V I T Y D O W N )

H A R N E S S A S S E M B L Y , 8 4 " L G .

( P O W E R D O W N )

S W I T C H & C A B L E

S C R E W , S E L F T A P P I N G # 1 0 2 4 X 1 " L G .

S W I T C H B O O T S E A L

C A B L E A S S E M B L Y , 2 0 0 A M P S , 3 8 ' L G .

K I T , M E G A F U S E ( 2 0 0 A M P F U S E & H E A T S H R I N K T U B I N G )

TABLE 30-1

6

(TO

POWER

UNIT)

5

!!!!!

WARNING

Do not attach cable to battery until liftgate repairs are completed.

LONG END TO PUMP

MOTOR SOLENOID

FIG. 30-2

30

HYDRAULIC SYSTEM DIAGRAMS

HYDRAULIC SCHEMATIC (GRAVITY DOWN)

HYDRAULIC CYLINDERS

3 GPM FLOW

CONTROL VALVE

PRESSURE PORT

VALVE A

RELIEF VALVE

(SET AT 3250 PSI)

CHECK VALVE

RETURN PORT

FILL HOLE

(PLUGGED)

PUMP

FILTER

M

MOTOR

(REFERENCE)

RESERVOIR

FIG. 31-1

DRAIN HOLE

(PLUGGED)

31

HYDRAULIC SYSTEM DIAGRAMS

HYDRAULIC SCHEMATIC (POWER DOWN)

HYDRAULIC CYLINDERS

3 GPM FLOW

CONTROL VALVE

PORT A - RAISE

VALVE

A

CHECK VALVE

PORT B - LOWER

(POWER DOWN)

VALVE

B

FILL HOLE

(PLUGGED)

MOTOR

(REFERENCE)

M

CHECK VALVE

RELIEF VALVE

(SET AT

3250 PSI)

PUMP

CHECK VALVES

FILTERS

RESERVOIR

RELIEF VALVE

(SET AT

400 PSI)

FIG. 32-1

DRAIN HOLE

(PLUGGED)

32

ELECTRICAL SYSTEM DIAGRAMS

ELECTRICAL SCHEMATIC (GRAVITY DOWN)

CONTROL SWITCH

MOTOR

CABLE

ASSEMBLY

WHITE

WHITE

RED YELLOW

GREEN BLACK

SOLENOID,

VALVE A

STARTER

SOLENOID

THERMAL

SWITCH

CABLE WITH

200 AMP FUSE

BATTERY

FIG. 33-1

33

CABLE

ASSEMBLY

YELLOW

BLACK

ELECTRICAL SYSTEM DIAGRAMS

ELECTRICAL SCHEMATIC (POWER DOWN)

CONTROL SWITCH

RED

GREEN

WHITE

WHITE

SOLENOID,

VALVE B

BOTTOM

STARTER

SOLENOID

(LOWERING)

THERMAL

SWITCH

(IN MOTOR

CASING)

TOP

STARTER

SOLENOID

(RAISING)

SOLENOID,

VALVE A

MOTOR

CABLE WITH

200 AMP FUSE

BATTERY

FIG. 34-1

34

RECOMMENDED BOLT TORQUES

CAUTION

The torque values in the following table are provided for torquing Grade 8 bolts on Liftgate mechanical parts. To prevent damage, never use the information in this table for torquing electrical or hydraulic hose connections on the Pump Assembly.

GRADE 8 BOLT TIGHTENING TORQUE

DIAMETER & THREAD

PITCH

TORQUE

1/4"-20

1/4"-28

5/16"-18

5/16"-24

3/8"-16

3/8"-24

7/16"-14

7/16"-20

1/2"-13

1/2"-20

9/16"-12

9/16"-18

5/8"-11

5/8"-18

3/4"-10

3/4"-18

10-14 LBS.-FT.

11-16 LBS.-FT.

20-29 LBS.-FT.

22-33 LBS.-FT.

35-52 LBS.-FT.

40-59 LBS.-FT.

56-84 LBS.-FT.

62-93 LBS.-FT.

85-128 LBS.-FT.

96-144 LBS.-FT.

123-184 LBS.-FT.

137-206 LBS.-FT.

170-254 LBS.-FT.

192-288 LBS.-FT.

301-451 LBS.-FT.

336-504 LBS.-FT.

TABLE 35-1

35

TROUBLESHOOTING

PLATFORM WILL NOT RAISE

1. Use voltmeter to verify that power is being supplied to Solenoid Terminal “A”

(FIG. 36-1.) Recharge the battery if less than 12.6 volts.

CAUTION

Keep dirt, water and other contaminants from entering the hydraulic system. Before opening the hydraulic fluid reservoir filler cap, drain plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination during maintenance.

2. Fill Reservoir to within 1/2” below the top with the hydraulic fluid recommended in the

Periodic Maintenance Checklist.

3. Touch a jumper wire to terminals “B” & “C” (FIG. 36-1). If motor runs check Switch, switch connections, and White wire. Check and correct wiring connections or replace the

Switch.

4. Touch heavy jumper cables to terminals “A” & “B” (FIG. 36-1).

a. If motor runs, replace the motor solenoid.

b. If motor does not run, repair or replace the pump motor.

NOTE: In most cases, you can avoid having to bleed the hydraulic system by correctly positioning Liftgate Platform before opening hydraulic lines. Refer to following procedure.

Save time on the job and prevent accidental fluid spills and hazards.

5. Check for structural damage and replace worn parts.

6. Check filter in the pump Reservoir. Replace filter if necessary.

7. Check for dirty pump motor relief valve. Clean if necessary.

Replace any worn out relief valve parts.

TERMINAL “B”

TERMINAL “C”

TERMINAL “A”

STARTER

SOLENOID

LOWERING

SOLENOID

FIG. 36-1

36

PLATFORM RAISES BUT LEAKS DOWN

1. Check if Solenoid Valves are constantly energized by touching a screwdriver to the top nut of the Solenoid (FIG. 37-1).

Try pulling the screwdriver away from the solenoid. If the solenoid nut attracts the screwdriver (magnetically) without pushing the toggle switch, the control circuit is operating incorrectly. Check if toggle switch, wiring or coil are faulty.

COIL

FIG. 37-1

CAUTION


NOTE: In most cases, you can avoid having to manually bleed Hydraulic System by correctly positioning Liftgate Platform before disconnecting any Lifting Cylinder high pressure Hydraulic Lines. The following procedure can save t ime and prevent accidental fluid spills and hazards.

2. Check the Valve Stem by removing the Coil

Assembly (Item 1, FIG. 37-2). With platform on ground, unscrew the Valve Stem, (Item 2,

FIG. 37-2) from the Pump. Push on the plunger that is located inside the Valve Stem by inserting a small screwdriver blade in the end. If the

Plunger does not move freely (approximately 1/

8”) replace the Valve Stem. When re-installing valve stem, torque hex nut to 30 in-lbs.

1

FIG. 37-2

1/8”

2

3. Check the Hydraulic Cylinder. With the Platform on the ground, remove the hydraulic line from the

Down Port of the Cylinder (FIG. 37-3). Raise the Platform even with the bed. Allow pump motor to run two seconds more while you watch for hydraulic fluid at the Down Port. A few drops of hydraulic fluid escaping the Down Port is normal; however, if it streams from the Down

Port, Piston Seals are worn. Replace Seals.

DOWN PORT

RAISE PORT

FIG. 37-3

37

TROUBLESHOOTING

PLATFORM RAISES PARTIALLY AND STOPS

CAUTION


1. Lower the opened Platform to the ground. Fill the Pump Reservoir on Gravity-Down

Liftgates to within 1/2” below the top with hydraulic fluid recommended in Periodic

Maintenance Checklist.

2. Use voltmeter to verify that the Battery shows 12.6 volts or more.

3. Check for Structural damage, or poor lubrication. Replace worn parts.



4. Check the Hydraulic Cylinder. With the Platform on the ground, remove the Breather Plug or Vent Line from the

Vent Port of the Cylinder (FIG. 38-1). Raise the Platform even with the bed. Allow pump motor to run two seconds more while you watch for hydraulic fluid at the Vent Port.

A few drops of hydraulic fluid escaping the Vent Port is normal; however, if it streams from the Vent Port, Piston

Seals are worn. Replace Seals.

VENT PORT

PRESSURE

PORT

FIG. 38-1

5. Check Filter in the Pump Reservoir. Replace filter if necessary.

6. Check for dirty pump motor relief valve. Clean if necessary. Replace any worn out relief valve parts.

38

LIFTGATE WILL NOT LIFT RATED CAPACITY

1. Use voltmeter to verify that the Battery shows 12.6 volts or more under load from pump motor.

2. Check for Structural damage or lack of lubrication.Replace worn parts.

!!!!!

CAUTION




3. With Platform on the ground, remove the pressure hose and fitting from the Pump and replace it with a 0-3000

PSI Pressure Gauge. Hold the switch in the “UP” position. Adjust the Relief Valve on the side of the Pump until the gauge shows 2800 to 3000 PSI (FIG. 39-2). Remove guage and re-install pressure hose.

VENT PORT

PRESSURE

PORT

4. Check for dirty pump motor relief valve. Clean if necessary. Replace any worn out relief valve parts.

FIG. 39-1

5. Check the Hydraulic Cylinder. With the Platform on the ground, remove the Breather Plug or Vent Line from the

Vent Port of the Cylinder (FIG. 39-1). Raise the

Platform even with the bed. Allow pump motor to run two seconds more while you watch for hydraulic fluid at the

Vent Port. A few drops of hydraulic fluid escaping the

Vent Port is normal; however, if it streams from the Vent

Port, Piston Seals are worn. Replace Seals.

RELIEF

VALVE

ADJUST

SCREW

6. If Pump cannot produce 2800-3000 PSI with a minimum of 12.6 Volts available, the Pump is worn and needs to be replaced.

39

PRESSURE

GAUGE

FIG. 39-2

TROUBLESHOOTING

PLATFORM RAISES SLOWLY

1. Use voltmeter to verify that power is being supplied to

Solenoid Terminal “B”. Recharge the battery if voltmeter indicates less than 12.6 Volts ( FIG. 40-1).

CAUTION


TERMINAL

“B”

FIG. 40-1

2. Check the Hydraulic Cylinder. With the Platform on the ground, remove the Breather Plug or

Vent Line from the Vent Port of the Cylinder (FIG. 40-3). Raise the Platform even with the bed. Allow pump motor to run two seconds more while you watch for hydraulic fluid at the

Vent Port. A few drops of hydraulic fluid escaping the Vent Port is normal; however, if it streams from the Vent Port, Piston Seals are worn. Replace Seals.



3. Check and clean Flow Control Valve in high pressure hydraulic line attached to Pump

Mounting Plate. When installing Flow Control Valve, make sure it is pointing to the direction of restricted fluid flow (pointing up and back toward pump) (FIG. 40-3).

4. Lower the opened Platform to the ground. Fill the Pump

Reservoir on Gravity-Down Liftgates to within 1/2” below the top with hydraulic fluid recommended in

PRESSURE

GAUGE

RELIEF

VALVE

ADJUST

SCREW

Periodic Maintenance Checklist.

5. Verify the Pump Motor is grounded to vehicle frame.

Make sure external tooth lock washer is installed under

Pump mounting screw and flat washer (FIG. 40-3).

7. Check for structural damage or poor lubrication. Replace worn parts.

8. Check the Filter in the Pump Reservoir.

Replace if necessary.

FIG. 40-2

6. Check for leaking hoses and fittings. Tighten or replace as required.

PUMP MOUNTING

PLATE

SCREW,

LOCK WASHER &

EXTERNAL TOOTH

LOCK WASHER

VENT PORT

9 . With Platform on the ground, remove the pressure hose and fitting from Pump and replace it with a

0-3000 PSI Pressure Gauge. Hold the Control

Switch in the “RAISE” position. Adjust the Relief

Valve on the side of the Pump until the gauge shows 2800 to 3000 PSI (FIG. 40-2). Remove guage and reinstall pressure hose.

FIG. 40-3

PRESSURE

PORT

FLOW

CONTROL

VALVE

40

PLATFORM WILL NOT LOWER, LOWERS TOO SLOWLY, OR LOWERS

TOO QUICKLY

1. Use voltmeter to verify that power is being supplied to

Solenoid Terminal “B”. Recharge the battery if voltmeter indicates less than 12.6 Volts ( FIG. 41-1).

2. Check for structural damage or poor lubrication.

Replace worn parts.

3. Check if Solenoid Valve is getting power by holding a screwdriver against the top nut of the Solenoid. Push

Control Switch to “LOWER” position to energize solenoid (FIG. 41-2). A good solenoid will attract

(magnetically) the screwdriver to the nut and make it difficult to pull the screwdriver away from the nut.

TERMINAL

“B”

FIG. 41-1

CAUTION




4. Check the Valve Stem by removing the Coil Assembly

(Item 1, FIG. 41-2). With platform supported, unscrew the Valve Stem (Item 2, FIG. 41-2) from the Pump.

Push on the plunger located inside the Valve Stem by inserting a small screwdriver blade in the end. If the

Plunger does not move freely (approximately 1/8”) replace the Valve Stem.

5. Check if filtering screen on solenoid valve is plugged. Clean carefully if required.

6. Check and clean Flow Control Valve in high pressure hydraulic line attached to Pump.

PUMP

7. Check if Flow Control Valve (FIG. 41-3) is pointing to the direction of restricted fluid flow

(pointing up and back toward pump). If required, remove Flow Control Valve and install it correctly (FIG. 41-3).

VENT PORT

1

2

FIG. 41-2

1/8”

PRESSURE

PORT

FLOW

CONTROL

VALVE

FIG. 41-3

41

Maxon GPTLR SERIES (2004 Release) Maintenance Manual

MAINTENANCE MANUAL

11921 Slauson Ave.

Santa Fe Springs, CA. 90670

LIFT CORP.

CUSTOMER SERVICE:

TELEPHONE (562) 464-0099 TOLL FREE (800) 227-4116

FAX: (888) 771-7713

WARRANTY/ RMA POLICY & PROCEDURE

TABLE OF CONTENTS

S

LIFTGATE TERMINOLOGY

PERIODIC MAINTENANCE

PERIODIC MAINTENANCE CHECKLIST

!!!!!

Annually or 5000 Cycles (whichever occurs first)

Semi-annually or 2500 Cycles (whichever occurs first)

Quarterly or 1250 Cycles (whichever occurs first)

PERIODIC MAINTENANCE

CHECKING HYDRAULIC FLUID

PERIODIC MAINTENANCE

CHANGING HYDRAULIC FLUID

GRAVITY DOWN LIFTGATES

POWER DOWN LIFTGATES

PERIODIC MAINTENANCE

REPLACING PLATFORM TORSION SPRING

!!!!!

PARTS BREAKDOWN

GPT MAIN ASSEMBLY

MAIN FRAME, LIFTING ARMS, & PARALLEL ARMS

GPT 25 & GPT-33

MAIN FRAME, LIFTING ARMS, & PARALLEL ARMS

GPT 25 & GPT-33

PLATFORM & FLIPOVER ASSEMBLY

PLATFORM ASSEMBLY

PUMP COVER & MOUNTING PLATE ASSEMBLY

GRAVITY DOWN HYDRAULIC COMPONENTS

12 VDC POWER UNIT (GRAVITY DOWN)

POWER DOWN HYDRAULIC COMPONENTS

12 VDC POWER UNIT (POWER DOWN)

DECALS

CONTROL SWITCH AND POWER CABLE

!!!!!

HYDRAULIC SYSTEM DIAGRAMS

HYDRAULIC SCHEMATIC (GRAVITY DOWN)

M

HYDRAULIC SYSTEM DIAGRAMS

HYDRAULIC SCHEMATIC (POWER DOWN)

M

ELECTRICAL SYSTEM DIAGRAMS

ELECTRICAL SCHEMATIC (GRAVITY DOWN)

ELECTRICAL SYSTEM DIAGRAMS

ELECTRICAL SCHEMATIC (POWER DOWN)

RECOMMENDED BOLT TORQUES

TROUBLESHOOTING

PLATFORM WILL NOT RAISE

PLATFORM RAISES BUT LEAKS DOWN

TROUBLESHOOTING

PLATFORM RAISES PARTIALLY AND STOPS

LIFTGATE WILL NOT LIFT RATED CAPACITY

!!!!!

TROUBLESHOOTING

PLATFORM RAISES SLOWLY

PLATFORM WILL NOT LOWER, LOWERS TOO SLOWLY, OR LOWERS

TOO QUICKLY

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