CONTROL VALVES
SUBSECTION 5C
REMOVAL. To remove the valve, proceed as follows (see
4. Insert the stem and piston assembly into sleeve (17) and
push it all the way into place. Place washer (06) over the
piston end and place spring (05) against the washer.
1. Perform the steps outined in the topic, General Re-
moval, at the beginning of this section.
5. Install O-ring (02) on end plug (01), and place the plug
with snap ring (03) and washer (04) installed, into the end of
2. Remove the covers from over the brake valves.
the valve. Rotate the end plug into the valve body until it is
3. Disconnect the hydraulic line at the back of the valve and
tight. Do not overtighten the plug.
the two lines attached to valve block (21).
6. Place O-rings (20 and 22), washer (21) and seal (25) on
4. Remove cotter pin (28) and pin (29) securing the brake
end plug (23). Place the end plug over stem (13) and work it
valve stem to support plates (18 and 30).
on the stem and into place carefully so that O-ring (20) will
5. Remove adjusting nut (01), washer (02), spacer (04) and
not be cut. Install retaining ring (24). Place rubber boot (26)
spring (03) from adjusting rod (05).
on the stem and wire it in place.
6. Pull cotter pins (11), washers (09), and pin (10) from the
7. Just prior to installation of the valve, place an O-ring (18)
pedal and support plates. Lift the valve assembly out of the
in each of the five counterbores in the feet of the valve body.
machine.
INSTALLATION. To install the valve, proceed as follows (see
7. Remove cotter pin (33) from rod (05) and valve (24).
Separate valve (24) from valve block (21) by removing cap-
1. Set the valve on the mounting bracket and secure with
screws (31) and washers (32).
capscrews and lockwashers.
REPAIR. To repair the valve, proceed as follows (see Figure
2. Connect the valve stem to support plates (18 and 30)
5C-8):
with pin (29), washers (19) and cotter pin (28).
1. Using a suitable tool, press in on gland (15) and remove
3. Attach the hydraulic lines to the brake valve.
retaining ring (11) from body (01).
4. Start the engine and operate the brake pedal. Observe
2. Remove stem (14), gland (15), spring (09), and spool (08).
the valve for leaks, binding or other problems.
ADJUSTMENT. After the valve has been installed, check
3. Remove O-ring (10), seal (12) and wiper (13) from gland
linkage adjustment as follows (see Figure 5C-6):
(15) and replace with new parts from the seal kit.
1. Adjust the brake band linkage as explained in Subsec-
4. Turn plug (04) out of body (01), remove O-ring (03) and
tion 7E.
replace with a new O-ring.
2. Bleed air from the system as described in Subsection 5A.
5. Clean and inspect the other parts for damage. Any defect
to parts, other than the ones found in the seal kit, will
3. With the pedal in the released position, adjust the spring
require the replacement of the valve.
length to 4-1/8" by turning adjusting nut (01).
6. Lubricate the parts with clean hydraulic oil.
NOTE
7. Install spool (08) into the body with the grooved end
The 4-1/8" spring length is the recommended set-
facing orifice plug (04).
ting, however this length can be Increased (for softer
pedal) or decreased (for harder pedal). Spring length
8. Place spring guide (07), spring (D6), and new washer (05)
must never exceed 4-1/4" for load handling.
into the body of the valve. Then install and tighten orifice
plug (04).
4. Check brake pedal travel distance. This dimension should
be approximately 7.0 inches If the travel exceeds 8.75
9. Assemble spring guide (02), spring (09) and gland (15) on
inches, check the brake band for proper adjustment and
to stem (14) and place in the body. CarefuIly press gland (15)
then bleed the brake as described in Subsection 5A.
into the body to prevent damage to the wiper. Install retain-
ing ring (11).
NOTE
NOTE
If the pedal "pumps up" or changes position, check
that the brake cylinders are retracting fully when the
The purpose of the wiper is to prevent dirt and water
brake pedal is fully released. Also check that the
from entering the valve, therefore the lips face out-
spring length adjusted in step 3 is 4-1/2" or less
ward. The O-ring and seal prevent oil leakage from
the valve.
5. Install the brake valve cover plates.
INSTALLATION. To Install the valve, proceed as follows (see
PRESSURE REGULATING VALVE (36U258)
1. Place two new O-rings on valve (24) and attach the valve
DESCRIPTION. This valve is used in conjunction with brake
to valve block (21) with capscrews (31) and lockwashers
valve (36U259) to apply the front and rear brakes The valve
(32).
provides power assistance during hard brake pedal applica-
2. Attach the valve stem to rod (05) with cotter pin (33).
tions.
5C-8