Drive Motor; Description; Shaft Seal Replacement; Drive Motor Cross Section - JLG 1850SJ Service And Maintenance Manual

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.
1
12
11
10
9
8
37. Bias Spring 41. Shaft Seal
38. Servo Piston 42. Bearing
39. Swashplate 43. Slipper
40. Output Shaft 44. Piston
Figure 3-15. Drive Motor Cross Section
3121619
2
3
4
5
6
7
45. Valve Plate
46. End Cap
47. Cylinder Block
48. Minimum Angle Stop
SECTION 3 - CHASSIS & TURNTABLE

Shaft Seal Replacement

REMOVAL
1. Remove snap ring (1) retaining shaft seal, and support
washer.
1
2
3
1. Snap Ring
2. Support Washer
3. Shaft Seal
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.
3-23