VALVE GP-MAIN CONTROL 3210036 - Caterpillar

Procedure For Adjustment Of Parking Brake
When some tests and adjustments are made to the transmission, the parking brake must be OFF. To prevent movement of the machine and personal injury, do the procedures that follow: a. Lower the bulldozer and ripper to the ground.b. Put blocks in front of and behind the tracks.c. Let only approved personnel on the machine and keep other personnel off the machine and in clear view of the operator.d. Keep the transmission selector in neutral when making adjustments.
1. With parking brake lever (1) located as shown in the brake ON position, adjust rod (2) until the end fits freely in lever (1). See Illustration 1.
Illustration 1. Location of components for parking brake adjustment.2. Tighten locknut on rod (2) to a torque of 5 0.5 N m (4 .5 lb ft).3. Disconnect rod assembly (3) at its upper end.4. Pull up on lever (4) until resistance is felt [do not stretch spring can on rod (3) if so equipped] and adjust the length of rod assembly (3) until the pin fits freely through upper rod end (5).5. To check parking brake adjustment, install a 0 to 4000 kPa (0 to 600 psi) pressure gauge on either the right or left brake pressure tap. See Illustration 2.
Illustration 2. Location of left (A) and right (B) brake pressure taps.6. Start the engine and run it at low idle.7. With parking brake lever (1) in the brake ON position (lever down), the pressure gauge must read less than 300 kPa (44 psi). If the pressure is not less than 300 kPa (44 psi), make rod assembly (3) shorter and check the pressure again.8. Rotate parking brake lever (1) to the brake OFF position (lever up). The pressure gauge must read 2750 150 kPa (400 22 psi). If the pressure reading is low, make rod assembly (3) longer and check the pressure again.9. After adjusting the linkage in Steps 7 and 8, attach a 0 to 4000 kPa (0 to 600 psi) gauge to the P1 pressure tap on the transmission. See Illustration 3. With the engine running at low idle, move the parking brake lever from brake ON to brake OFF (full lever travel each way). The P1 pressure should read exactly the same with the parking brake ON or OFF.
Illustration 3. Location of P1 pressure tap on the transmission.10. If the P1 pressure is not the same with the parking brake ON as it is with the parking brake OFF, the parking brake valve is leaking oil and the linkage must be adjusted further follows: a. If the P1 pressure is less with the parking brake OFF than with the parking brake ON, lengthen rod assembly (3).b. If the P1 pressure is less with the parking brake ON than with the parking brake OFF, shorten rod assembly (3).11. If linkage adjustments are made in Step 10, repeat the pressure checks in Steps 7, 8, and 9. Adjust as necessary until all pressures are correct.