5540F/YB5515 SERVICE MANUAL
9-16 Published 10-21-2010, Control# 198-04
hydraulic system. Keep all parts free of contaminants,
dirt and debris.
NOTE: Coat the surfaces indicated Figure 9-28 with a
Lithium Base, E.P. No. 2 bearing grease or
equivalent.
19. Install new lining 25 Figure 9-28 in housing 26 using new
bushings 24 and pan head screws 27. Tighten the
screws to 22-28 lb-in. (2,5 - 3,3 Nm).
20. Install new lining 20 on piston 19 using new flat head
screws 21. Tighten screws to a torque of 30-40 lb-in (3,4
- 4,5 Nm). Install new o-rings 18 on piston 19 and insert
lining and piston assembly 22 into housing 26 bore.
21. Carefully install two new seals 28 in housing 26. Be sure
to install the seals the same direction as they were
removed.
22. Install bleed screw 30. Tighten to a torque of 9-15 lb-ft
(12,2 - 20,3 Nm).
23. Install new o-rings 13 and 16 and new backup rings 14
and 17 on piston 15. Be sure they are installed in the
correct order.
24. Install piston 15 into housing 26 bore. Be sure piston is
installed in the correct direction. Be careful not to pinch
the o-rings on the inlet ports.
25. Install new backup ring 10 and new o-ring 11 on piston 9.
Be sure they are installed in the proper order. Install
push rod 12 in bore of piston 9. Install piston into
housing 26 bore.
26. Fully lubricate the threads of adjusting screw 7 and lock
nut 9 and install into cover 3.
27. Install washer 6, if used, and new belleville springs 5
over end of piston 9. Follow the
stacking sequence
Figu
re 9-30.
28. Install new seal 4 in cover 3. Be sure inside of cover is
coated with grease.
29. Install new gasket 23, cover 3, lockwashers 2 and
capscrews 1. Tighten the screws evenly in the order of
A, B, C and D Figure 9-29. When installed, tighten each
screw to a torque of 22-27 lb-ft (29,8 - 36,6 Nm).
30. Assemble the brake assembly onto the mounting
bracket 31.
31. Install the parking brake assembly onto the frame of the
crane.
32. Attach the hydraulic hose.
33. Adjust the lining clearance as described on page 9-6.
34. Open the accumulator needle valve and then bleed air
from the system as described on page 9-5.
Seal Kit Installation
The parking brake has a seal kit available. It includes all the
parts necessary to replace all the seals in the brake These
parts are indicated in Figure 9-28 with a symbol.
NOTE: The needle valve must be in the open position for
the brake system to operate properly. If it is not
open, the charging pump will cycle every time the
brake pedal is depressed and if the crane’s engine
stops there may not be enough pressure to stop
the crane.
NOTE: When removing seals and backup rings be careful
not to scratch or mar the pistons.
NOTE: The linings must be kept free of grease, oil, etc.
1. Close the needle valve located under the accumulator
Figure 9-11. This will shut off hydraulic pressure to the
parking brake. Release system pressure by actuating
the service brake pedal until no resistance is felt. Then,
engage and disengage the parking brake to release its
pressure.
2. Slowly, loosen the hydraulic hose from the parking
brake. Some pressure may still be present in the
hydraulic hose. Let the pressure escape and then
remove the hydraulic hose.
3. Cap the hydraulic hose to prevent contamination from
entering the hydraulic system.
4. Loosen lock nut 8 Figure 9-28 and back off adjusting bolt
7.
WARNING
Before replacing the parking brake seals, make sure that
the machine is on level ground. Place chocks on both
sides of the four tires. Remove the ignition key. If these
precautions are not adhered to, the crane could run you
over while performing the repair.
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