Repair and Replacement of Control Valve Parts

TM 10-3930-609-35

3-57. Repair and Replacement of Control Valve

e. Place packing in groove of poppet and insert

Parts

poppet into bearing. Place spring on poppet and spring

seat on spring.

a. Replace all parts found to be defective during

disassembly and inspection.

f. Screw relief valve plug into valve body and

screw adjusting setscrew into relief valve plug. Install

Note

jamnut on adjusting setscrew but leave loose.

If either of the plungers or the valve

g. Install remaining plugs in valve body.

body is defective to extent of being

h. Adjust relief valve portion of control valve as

unserviceable, replace entire control

follows:

valve assembly.

(1) Connect pressure part of control valve to

b. Repair minor thread damage with tap or thread

a hydraulic test pressure source of 2,000 psig with a flow

chaser.

rate of 4 gallons per minute (or greater).

c. Remove minor surface defects from parts with

(2) Connect hydraulic test source return hose

crocus cloth (Specification P-C-458).

to return port on control valve and temporarily plug

d. Replace all packings with new parts at each

unused ports in valve body.

reassembly.

(3) Raise either plunger and note test

pressure. If test pressure is not within the range of

3-58. Reassembly of Control Valve (fig. 3-11)

1,600 to 1,700 psig, turn adjusting setscrew clockwise to

a. Install packings for plungers in valve body

increase pressure or counterclockwise to decrease

pressure.

bores; then, insert plungers.

(4) When relief valve pressure is properly set,

b. Place washers on ends of plungers. Then,

tighten jamnut on adjusting setscrew and install relief

install springs using spring retainer and screws.

valve nut over end of setscrew.

c. Screw plugs to which gaskets have been applied

(5) Disconnect control valve from test

into valve body to cover springs and tighten securely.

pressure source and remove temporary plugs.

d. Insert bearing into valve body and screw

associated plug into valve body.

3-59. Installation of Control Valve

Refer to paragraph 2-17 for installation procedure.

Section IX. REPAIR OF TILT CYLINDER

3-60. Description of Tilt Cylinder

d. Carefully pull piston and rod out of cylinder and

The tilt cylinder is a double-acting type hydraulic

remove spacer, piston packings and piston guide from

cylinder having a three inch bore and a 31/4 inch stroke.

piston and rod.

Two cylinders are used on the truck to tilt the upright

assembly.

3-63. Cleaning Disassembled Parts of Tilt Cylinder

a. Wash metallic parts in SD and dry with

3-61. Removal of Tilt Cylinders

compressed air under moderate pressure or with clean

Removal of tilt cylinders from the truck will be required

cloth.

for repair as described in the following instructions (TM

b. Be sure to clean parts thoroughly to facilitate

10-3930-609-12).

inspection.

3-62. Disassembly of Tilt Cylinder (fig. 3-12)

3-64. Inspection of Tilt Cylinder Parts

a. Remove screw, nut and lockwasher and

a. Inspect all threaded and tapped parts for

unscrew rod end from piston and rod.

stripped threads or other thread damage.

b. Remove two screws and washers which secure

b. Inspect packing retainer, stuffing box, piston

packing retainer to stuffing box, slide packing retainer

and rod, and cylinder for cracks and distortion.

off piston and rod and pry wiper ring out of packing

c. Inspect bore in cylinder for scratches, scoring,

retainer.

pitting and other surface defects.

c. Unscrew stuffing box from cylinder; then,

remove packing and backup ring from groove in stuffing

3-65. Repair and Replacement of Tilt Cylinder Parts

box and remove packing from recess in stuffing box.

a. Repair minor thread damage with tap, thread file

or thread chaser.

3-20