Hydraulic Motor Rebuild
12 310778N
Hydraulic Motor Rebuild
Removal
1. Place drip pan or rags under sprayer to catch hydraulic oil
that leaks out during repair.
2. Remove pump pin (92) and retainer clip (120), page 15.
3. Fig. 5. Remove hydraulic lines (93, 95) from fittings (16) at
top left and right side of hydraulic motor.
4. Loosen jam nut (65).
5. Unscrew and remove hydraulic motor cap (64).
6. Slide piston rod/hydraulic motor cap assembly (A) from
hydraulic motor cylinder.
7. Remove yoke (78).
a. Fig. 5. Clamp hydraulic motor cap in vise with
hydraulic motor piston rod facing up.
b. Use shortened Allen wrench to remove two screws
(13) from spring retainer (83). Remove yoke, spring
retainer, piston and trip rod assembly from hydraulic
motor cap.
c. Cover spring retainer (83) with a rag to contain detent
spring (20) and balls (8) when they are removed from
yoke. Remove detent balls and spring. Remove
spring retainer.
d. Put yoke in vise and remove piston rod assembly
from yoke.
Installation
1. Fig. 5. Put hydraulic motor cap (64) in vise.
2. Install yoke, spring retainer, piston and trip rod assembly
in hydraulic motor cap. Use shortened Allen wrench to
install two screws (13) in spring retainer to secure piston
rod assembly to hydraulic motor cap.
3. Slide piston rod assembly (A) into hydraulic motor
cylinder (67).
4. Screw down hydraulic motor cap (64). Unscrew hydraulic
motor cap until inlet and outlet align with hydraulic line
fittings and test hole in hydraulic motor cap points toward
belt guard (117).
5. Torque jam nut (65) against hydraulic motor cap (64) to
150 ft-lb (17 N·m).
6. Fig. 5. Install hydraulic lines (93, 95) to fittings (16) to top
left and right side of hydraulic motor; torque to 40 ft-lb
(54.2 N·m).
7. Pull start rope slowly to align pin holes of hydraulic motor
and displacement pump (111). Connect with pump pin
(92); install retainer clip (120), page 15.
8. Start engine and operate pump for 30 seconds. Turn
engine OFF. Check hydraulic oil level and fill with Graco
hydraulic oil, page 6.
WARNIN G
Relieve pressure; page 6.
WARNIN G
FLYING PARTS HAZARD
Detent spring has high energy potential. If detent
spring is released without due care detent spring and
balls could fly into the eyes of the disassembler. Wear
safety glasses when removing or installing detent
spring and balls. Failure to wear safety glasses when
removing detent spring could result in eye injury or
blindness.
WARNIN G
FLYING PARTS HAZARD
Detent spring has high energy potential. If detent
spring is released without due care detent spring and
balls could fly into the eyes of the disassembler. Wear
safety glasses when removing or installing detent
spring and balls. Failure to wear safety glasses when
removing detent spring could result in eye injury or
blindness.