RR-250 RECLAIMER & SS-250 SOIL STABILIZER POWER TRAIN Ground Drive Hydraulic Motor Caterpillar

Ground Drive Hydraulic Motor

Remove And Install Ground Drive Hydraulic Motor

1. Remove the six bolts and remove the skid plate from the bottom of the machine.

2. Remove the high pressure hydraulic lines (1) and the case drain line and its fitting at the top of the hydraulic motor (2). Immediately cap or plug all openings.

3. Position a roller jack under the motor and remove the four bolts (3) that hold the motor to the ground drive transmission (4).

4. Pull the motor straight forward to disengage it from the coupling in the transmission, lower the motor and move it away. The motor weighs about 40 kg (88 lbs).

NOTE: The following steps are for installation of the ground drive hydraulic motor.

5. Install a new O-ring on the nose of the motor housing.

6. Place the motor (2) on a roller jack and move it into position with the coupling at the front of the transmission (4). The motor may have to be rotated slightly to engage the spline of the motor shaft into the spline of the coupling.

7. Move the motor inward into coupling until the mounting flange is against the transmission, and install the four mounting bolts (3).

8. Remove the caps or plugs and install the high pressure hydraulic lines (1) back to the motor.

9. Fill the motor case through the top case drain opening with filtered ATF Type F oil, and then connect the case drain fitting (6) and hydraulic line back to the opening.

------ WARNING! ------

Make sure the transmission shift lever is in one of the two neutral positions before the engine is started. Injury to personnel could result as the hydraulic motor is tested and purged of air.


NOTE: The travel control lever must be in the neutral position and the rotor clutch lever must be disengaged before the starter motor can be energized.

10. Start the engine and set throttle to lowest idle possible.

NOTE: Air can be purged from the high pressure lines by cracking (loosening slightly) the two high pressure gauge port plugs (7) at the top of the motor manifold assembly (8).

11. Cycle the pump slowly from forward to reverse with travel control lever until most of the air is purged from the high pressure gauge port plugs, then tighten the port plugs.

12. Increase engine speed to the maximum, and then check for forward and reverse operation of the machine.

Reference: For troubleshooting procedures, see the Troubleshooting section of the RR-250 and SS-250 Power Train Systems Operation, Testing and Adjusting, Form No. KEBR1237.

13. Continue to cycle the pump slowly from forward to reverse for 15 minutes, then stop the engine.

14. Check the hydraulic tank oil level and add oil if necessary.

15. Put the skid plate into position under the machine and install the six bolts.

Disassemble And Assemble Ground Drive Hydraulic Motor

Start By:

a. remove ground drive hydraulic motor

NOTE: The procedures that follow only cover minor repairs. Only personnel qualified in hydraulic pump and motor repair should attempt to do a complete disassembly and assembly.

1. Remove the large retaining ring (1) located on the shaft end of the motor (a Truarc #7 retaining ring pliers may be used). Remove the side of ring opposite the tangs from the groove before the tang side.

2. Remove the aluminum housing (2) by prying the housing toward the end of the shaft (3) until the O-ring is free. The housing is held in place by the friction of the O-ring around its outside diameter.


Handle the bronze sealing ring carefully because it can be damaged easily.

3. The bronze sealing ring (4) is also held in place by internal O-ring friction. Using hand force only, work the sealing ring free and slide it carefully off the spline of the shaft.

4. Remove the three O-rings.

NOTE: The following steps are for installation of the motor shaft seal. Always use new O-rings when the parts are reinstalled.

5. Lubricate the small O-ring with petroleum jelly and insert O-ring into the I.D. of the bronze sealing ring (4). Lubricate the other small O-ring and insert into the aluminum housing (2).


Protect the parts from damage by the spline of the shaft. Wrapping tape around the spline will provide a safe surface for the O-rings.

6. With the O-ring facing the motor, slide the bronze sealing ring (4) over the shaft spline and onto the shaft pilot diameter. Work the O-ring into position using only hand force until it snaps into place.

7. Insert the stationary seal pilot (7) into the aluminum housing (2), locating the notch in the stationary seal over the pin in the aluminum housing. The stationary seal should have a slight spring load due to the springs (5) in the housing.

8. Lubricate the large O-ring (6) and put into position on the housing (2).

NOTE: Make certain all six springs are in place in the aluminum housing before sliding it into position on the shaft.

9. Slide the aluminum housing assembly into position against the bronze sealing ring (4) using hand force only.

10. Compress the aluminum housing to expose the retaining ring groove, and install the retaining ring (1) into the groove with the beveled side out. Install the side opposite the tangs into the groove first, being certain that the retaining ring has snapped completely into its groove.

End By:

a. install ground drive hydraulic motor

Remove And Install Ground Drive Hydraulic Motor Manifold Assembly

1. Remove the six manifold assembly mounting bolts.

2. Remove the manifold assembly (1) from the motor end cover (2).

3. Remove the two backup rings and the three O-rings from the manifold assembly ports.

NOTE: The following steps are for installation of the motor manifold assembly.

NOTE: The manifold assembly is shown with the springs, spacers, spools and cartridges removed. It is not necessary to remove these parts from the manifold assembly in order to remove and install the manifold assembly as a unit.

4. Install O-ring (3) in the port (4) with the full counterbore.

5. Install the two O-rings (5) in the machined grooves (6) of the other two ports.

NOTE: The backup rings have a rectangular cross section and are slightly cupped on one side. Applying a small amount of clean grease to the cupped side will help to keep the backup ring in position against the O-ring during installation of the manifold assembly.

6. Install the backup rings (7) in the same machined grooves (6) with the cupped side against the O-ring (5).

7. Carefully put manifold assembly (1) into position on the motor end cover, making sure all O-rings and backup rings remain in place.

8. Install the six bolts (8) and tighten to a torque of 22 to 28 Nm (16 to 21 lb ft).

Remove And Install System Pressure Relief Valve

NOTE: The relief pressure of system pressure relief valves is factory set, and disassembly of the cartridge should not be attempted without qualified personnel and a complete hydraulic test bench to check both flow and pressure. The first two digits of a particular pressure setting (psi) are stamped on the end of the earlier valves, while later valves use alphabetical letters to designate pressure settings (psi) as follows:

A = 1000
B = 1500
C = 2000
D = 2500
E = 3000
F = 3500
G = 4000
H = 4500
J = 5000
K = 5500

1. Remove the system pressure relief valve (1) from either side of the manifold assembly (2) for inspection or replacement. These valves are interchangeable in either side of the manifold assembly, providing the pressure settings of both valves are the same.

2. Carefully install system pressure relief valve (1) back into manifold assembly (2) and tighten to a torque of 40 to 95 Nm (30 to 70 lb ft).

Remove And Install Shuttle Valve

1. Remove the two hex plugs (1), one from each side of the manifold assembly (2). Slide the springs, spacers and spool out of the manifold assembly.

NOTE: The following steps are for installation of the shuttle valve.


The spool and the manifold are sold as a matched set and cannot be replaced separately.

2. Install spool (3) into one side of the manifold assembly.

NOTE: The parts are interchangeable and can be installed in either side. The spacers must be installed between the springs and the spool.

3. Install the spacer (4) and spring (5) over the end of the spool. Install the hex plug (1) in the same side of the manifold assembly.

4. Install the other spacer (4) and spring (5) over the other end of the spool.

5. Install second hex plug and tighten both plugs to a torque of 80 to 135 Nm (60 to 100 lb ft).

Remove And Install Charge Pressure Relief Valve

1. Remove hex plug (1) from the manifold assembly (2). Remove the shims from the counterbore of the hex plug.

2. Remove the spring (3) and poppet (4) from the manifold assembly.

NOTE: The following steps are for installation of the charge pressure relief valve.


Do not alter the original shims unless new parts are used. The pressure setting may then have to be adjusted correctly with the use of new shims.

3. Install the shims in the counterbore of the hex plug (1).

4. Install the poppet (4), nose end in first, and then the spring (3) in the manifold assembly.

5. Install the shims in the counterbore of the hex plug (1), position the plug with the spring against the shims and install the hex plug in the manifold assembly.

6. Tighten the plug to a torque of 80 to 135 Nm (60 to 100 lb ft).