Adjustment. Western UniMount MVP

RELIEF VALVE INSPECTION AND ADJUSTMENT

Relief valve inspection

1.

Remove the valve stem, ball, spacer and spring.

2.

Look for broken or damaged parts, contamination or missing or damaged O-rings.

3.

If OK, place ball on hard wood block, hold stem seat on ball and lightly strike stem with a hammer.

CAUTION

Be careful to strike stem squarely. You can bend stem if you do not strike it squarely.

4.

Reassemble components into manifold block. Apply a light coat of anti-seize or grease to stem threads.

Adjustment

1.

Adjust by tightening the relief valve stem as much as possible

(until spring is fully compressed)

2.

Back off valve stem (rotate counterclockwise) the number of turns indicated in the chart.

Valve Manifold Block

Relief Valve

Pump Relief

Right or Left Cylinder

Primary Relief

Right or Left Cylinder

Secondary Relief

No. of Turns Backed Off

(CCW) From Fully Seated

2-1/2 - 2-3/4*

1-1/2 - 1-3/4**

1-1/4 - 1-1/2

Approximate

Relief Valve

Pressure (PSI)

1750

3000

3500

* Install a tee in line with the lift cylinder hydraulic hose and attach a

3000 psi gauge. Read the pressure at pump relief when holding the raise function button. Adjust pump relief valve to obtain 1750+/- 100 psi.

** Be certain the cylinder primary relief valve stem is backed out 1/4 turn farther than the secondary relief valve stem.

63

Spring

Spring Spacer

Ball

Valve Stem Seat

Valve Stem w/ O-rings

Lit. No. 21857 June 15, 2003