JLG 1850SJ Service Manual - Manual (Page 65)

SECTION 3 - CHASSIS & TURNTABLE
3121619 – JLG Lift – 3-23
3.11 DRIVE MOTOR
NOTE: Drive motor servicing is similar for all Series 45 hydraulic
motors. The physical appearance of your motor may be
slightly different than shown.
Description
Drive motors are low to medium power, two-position axial pis-
ton motors incorporating an integral servo piston. They are
designed for operation in open and closed circuit applications.
The standard control is a direct acting single line hydraulic
control. The integral servo piston controls motor displace-
ment.
Motors are spring biased to maximum displacement and
hydraulically shifted to minimum displacement. Minimum and
maximum displacement can be set with fixed internal stops.
The large diameter servo piston allows smooth acceleration
and deceleration with relatively large circuit orificing.
Figure 3-15. Drive Motor Cross Section
Shaft Seal Replacement
REMOVAL
1. Remove snap ring (1) retaining shaft seal, and support
washer.
Figure 3-16. Removing Shaft Seal
2. Remove support washer (2).
3. Carefully pry out shaft seal (3).
NOTE: To avoid damaging shaft during removal, install a large
sheet metal screw in chuck of a slide hammer. Drive screw
in seal surface and use slide hammer to pull seal.
4. Discard seal.
37. Bias Spring
38. Servo Piston
39. Swashplate
40. Output Shaft 41. Shaft Seal
42. Bearing
43. Slipper
44. Piston 45. Valve Plate
46. End Cap
47. Cylinder Block
48. Minimum Angle Stop
1
2
3
4
5
6 7
8 9
10
11
12
1. Snap Ring
2. Support Washer
3. Shaft Seal
1
2
3