PR-75 CUTTER CONTROL VALVE Cutter Control Valve Caterpillar

Cutter Control Valve
PR-75 CUTTER CONTROL VALVE Cutter Control Valve
1.1. Parts List
2.1. Dis-assembly:
3.1. Assembly:
4.2. Inlets
5.2. Outlets

Parts List

1. Nut
2. Mounting bracket
3. Washer
4. Outlet section
5. Mylar shim (between section)
6. O-ring (11 req'd)
7. O-ring
8. Inlet section
9. Tie rod
10. Body & spool S/A
11. O-ring (in-body)
12. Spring cap
13. Spring shaft
14. Spring guide
15. Spring
16. Closed center plug


NOTE: Before attempting to dis-assemble this or any other hydraulic component prepare a clean work area.

1. Remove nuts (1), mounting bracket (2) and washer (3) from inlet end of valve bank.

NOTE: When removing inlet section with "N" option load checks (see page 4, inlet illustration) watch for check balls, which will fall free from inlet section when removed. Also, remove ball retainers from inlet side of the first valve section.

2. Remove the inlet section (8). Between the inlet (8), each center section and the outlet (4), are three mylar shims (5), one over each tie rod (9). Keep these shims, as they will be needed during assembly.

3. Remove valve sections, one at a time, removing O-Rings (6) and mylar shims (5) between each section.

4. After valve bank is completely dis-assembled remove handle assemblies.


For "L" or "M" options only, limit switch must be removed before removing spring cap (see page 6, optional L & M for details).

5. Remove the spring cap (12) from the valve section. On detented spool sections the detent balls and spring may jump out of the detent cap.

6. Remove the spool from the body by pushing on handle end. KEEP BODY AND SPOOL TOGETHER, AS THEY ARE A MATCHED SET.

7. Remove O-Rings (11), from inside bore on handle end of body.

8. To remove the O-Ring (6) on the spool, first remove the spring centering or detent assembly, then the O-Ring.

9. Wash all parts in clean solvent, then dry with a low pressure air hose.


1. Inspect all parts before assembly. Remove any nicks or burrs from body and spool with fine crocus cloth.

2. Lubricate all O-Rings with clean oil.

3. Replace O-Ring (11) in bore on handle end of body. Use spool in body to guide O-Ring into groove. Make sure O-Ring is not twisted in groove.

4. Replace O-Ring (6) on spool making sure it is not twisted.

5. Replace spring centering or detent assembly on end of spool. Torque to 30 in. lbs. (see details on page 6).

6. Lubricate spool with clean hydraulic system oil. Place spool in it's bore with a slight twisting action, this will allow the O-Rings to compress and will prevent possibilities of the O-Ring shearing.

7. Replace the spring centering or detent cap. To ease assembly of detents extend the spool slightly out of the body, assemble balls and spring on the spool, then screw detent cap into the body.

NOTE: "L" or "M" limit switch (see page 6). Attach the switch bracket with the bushing nut. If the switch does not operate properly, it may be adjusted with the two screws that mount the switch to the bracket.


Excessive: tightening of switch mounting screws may crack switch housing.

8. Replace the handle assemblies.

9. Install one nut (1) on each tie rod (9). Place two tie rods through the mounting bracket (2). Place one flat washer (3) on the third tie rod. Push the tie rods through the outlet section (4). An aid in banking sections is to place the mounting bracket in a vice or on the edge of a flat surface with the tie rods in a vertical position. Place one mylar shim (5) over each tie rod and push them down onto the outlet sections. Place 5 O-Rings (6). Install a valve section over the tie rods. Place the O-Rings (6), (7) and mylar shims (5) on this section. Replace remaining section as above.

"N" Option, load checks (see page 4). Before installing O-Rings in the section next to the inlet, place the ball retainer (prongs up) in the flow passages on both sides of the center flow passage, not the two outboard passages. Place the O-Rings (7) in the counter-bores. Place the mylar shims, one over each tie rod, on the section. Then, stand the ball on the retainers.

10. Install the inlet section (8). Place the mounting bracket (2) over the lower tie rods and install the nuts (1). Place the flat washer (3) over the top tie rod and install the nut (1).

11. Torque the tie rods in three steps of 50 in. lbs., 90 in. lbs. and finally 115 in. lbs. THIS IS VERY IMPORTANT! OVERTORQUEING WILL CAUSE BORE DISTORTION & MAY CAUSE SPOOL BINDING OR INCREASED LEAKAGE.

12. In order to set the relief, if installed, the complete valve must be put on a test stand capable of flow from 1 to 5 GPM. Remove the cap over the adjustment screw and loosen the lock nut (see page 4). Set incoming pressure on test stand to desired valve setting and adjust screw in to increase relief setting or out to decrease relief setting. Setting is correct when 1 GPM flows out of valve at desired pressure.

13. If painting of the valve is required, make sure all ports are plugged, handles are removed, and spools masked.


1. O-ring
2. Seat
3. Retainer
4. Poppet
5. Adj. screw
6. O-ring (2)
7. Lock nut
8. Spring
9. Cap nutRepair Kit (1-9)

1. Seat
2. Piston
3. O-ring
4. Cap
5. Spacer
6. O-ring
7. Jam nut
8. Adj. screw
9. Spring
10. Spring
11. O-ring
12. Back up ring
13. Spring stop


1. Power beyond plug
2. Body
3. O-ring
4. Quad ring
5. Back up ring
6. O-ring (5)

Options "L" or "M" use Limit Switch