Remove Check Valves

HYDRAULIC

3. See that spools fit their respective body bores

a. remove screws and spool cap. Grasp

with a slight hand pressure and without perceptible side

spring end of spool and withdraw from

clearance.

valve body. Clamp spool in a soft-jawed

vice, compress spring.

b. Remove snap ring, spring retainer, spring,

4. If the spools are loose, scored or damaged or

and spring retainer from spool.

the valve body has damaged threads, cracks or scored

bores, the control valve should be replaced with a new

unit.

3. Remove Check Valves

5. Inspect the check valve poppet and its seating

a. Unscrew plug and remove O-ring.

face in the valve body for grooves or defects which may

cause leakage.

b. Remove spring guide, spring and poppet.

6. Check the poppet for free movement in the

NOTE: If necessary a soft wire hook with smooth ends

body bore. If the poppet appears to be faulty replace

may be used for removal of poppets. Check valve

with a new one. Small nicks and grooves can be

poppets should be identified so that when used in

removed from the poppet seating face in the body, by

reassembly, they can be returned to their respective

lapping poppet in body seat using a fine grain grinding

bores.

compound. Lap seat sufficiently to remove defects.

Thoroughly wash valve body to remove all traces of

4. Remove Relief Valve

grinding compound.

a. Remove plug and O-ring from body

7. Inspect the relief valve plunger and seat for

opposite relief valve.

ridges or scoring which may cause improper seating and

leakage. Replace parts if worn or damaged.

b. Unscrew and remove acorn nut, two seals

and jam nut.

8. Inspect covers for any breaks or separation of

brazing.

c. Back off adjusting screw to relieve spring

tension.

Remove cap with adjusting

9. Inspect springs for weakness or distortion.

screw installed.

Remove O-ring and

back-up ring from cap.

10. Inspect split flanges for cracks, damage, or

stripped threads.

d. Remove pilot plunger spring, pilot

plunger, pilot seat, large spring, poppet

assembly and seat from body bore.

11. Discard all O-rings, gaskets and wipers and

replace with new parts when reassembling the control

5. Remove plugs and O-rings from valve body.

valve.

D. CLEANING' INSPECTION AND REPAIR

12. After all parts have been inspected and valve is

not to be reassembled immediately, coat reusable parts

1. Wash all parts thoroughly in solvent.

with clean hydraulic oil.

2. Inspect the valve body bores and spools for

grooves, deep scratches or excessive wear.

B-151