User's Manual

Service
8 312484C
Hydraulic Motor Disassembly
NOTE: Repair Kit 247557 is available. For best results,
use all the parts in the kit. Kit parts are marked with an
asterisk in the Parts List.
When disassembling, lay out all parts in sequence, to
make reassembly easier. Clean and inspect all parts for
wear or damage before reassembling. Replace as nec-
essary.
1. Remove the hydraulic motor from the pump as
explained in the separate system manual. Lay it on
its side in a pan.
2. Unthread the tie rods (37) from the retainer (36) and
the tie plate, and pull them out through the top of the
hydraulic motor. It will be necessary to remove the
lower four nuts (27) and lockwashers (28).
3. Unscrew the four fluid tube nuts (N) and remove the
tubes (32, 39). See F
IG. 1. Allow excess oil to drain
from the hydraulic motor, then plug the fluid fittings.
4. Pull the top valve spool (1), cylinder (33), and dis-
placement rod (9) together off the bottom cylinder
cap (35). Remove the o-ring (2) from the bottom
cap.
5. Grasp the valve spool(1) and pull the cylinder (33)
off. Slide the cylinder off the displacement rod (9).
Be careful not to damage the rod. Remove the
o-ring (2) from the valve spool.
6. Lay the valve spool (1) and displacement rod (9) on
a table. Place a clean rag around the yoke (4) to
prevent the detent balls (3) from popping out. Push
the yoke (4) sideways off the valve sleeve (19) while
holding the balls (3) and spring (18) with the rag,
then carefully remove the balls and spring.
7. Inspect the valve sleeve (19), valve stop (25), and
spool (S) for damage. See F
IG. 2. If any of these
parts requires replacement, unscrew the two screws
(26) holding the stop (25) to the spool (S). Remove
the stop and slide the sleeve (19) off the spool. If the
spool is damaged, replace the valve spool (1).
NOTE: If any of these parts are being reused, thor-
oughly clean any adhesive residue from the screws and
female threads of the spool. Use a surface cleaner such
as chlorinated solvent on the threads and blow dry with
compressed air. If necessary, use a 10-24 unc-2b tap to
remove adhesive from the female threads.
8. Remove the capscrew (23), sealing washer (22) and
o-ring (24) from the cap plate (29). Lift off the cap
plate and remove the o-ring (20).
9. Hold the flats of the displacement rod (9) in a vise
and use a spanner wrench in the pin holes of the
piston (16) to screw it off the rod. Remove the trip
rod (17) from the displacement rod.
10. Unscrew the nut (48) and remove the retainers (11)
and spring (12) from the trip rod (17).
11. Slide the piston (16) off the trip rod (17). Remove
the bearing (5), seal (6), and o-rings (7 and 8) from
the piston.
12. Inspect the yoke (4) and trip rod (17) for damage. If
either part requires replacement, slide the yoke into
Repair Tool 189-305 and set the tool in a vise. See
F
IG. 2. Use a wrench on the flats of the trip rod and
unscrew the rod from the yoke.
13. Pull the housing retainer (36) away from the bottom
cylinder cap (35).
14. Remove the block packings (14 and 49), wiper (15),
bearing (13), and o-ring (2) from the housing
retainer and bottom cylinder cap.
NOTICE
Keep the hydraulic system clean. Always plug the
hydraulic inlets, outlets and lines when disconnect-
ing them for any reason to avoid introducing dirt and
other contaminants into the system.
NOTICE
Be careful not to scratch the outside of the displace-
ment rod.