Troubleshooting; Service Brakes - Manitowoc Grove 5540F Service Manual

5540F/YB5515 SERVICE MANUAL
1. Boot
2. Piston Assembly
3. Spring
4. Spring
5. Spring
6. Shim
7. Retainer Assembly
8. End Plug
9. O-ring
10. Spring
11. Spool
12. Housing
13. Screw
14. Cup
15. Seal
a0780

TROUBLESHOOTING

Service Brakes

PROBLEM
Warning light on instrument panel
illuminates.
No brakes.
Bad brakes (pedal fully applied, crane
gradually stops).
Soft brake pedal.
GROVE
Brake Modulating Valve
POSSIBLE CAUSE
1. Loss of brake pressure.
1. Faulty brake modulating valve.
2. Faulty priority flow control valve.
3. Loss of fluid from broken line,
loose fitting of hose.
4. Leakage past both brake pistons.
5. Faulty pump section.
6. Faulty accumulator
valve.
1. Severe wear in service brake
discs.
2. Leakage past one brake piston.
1. Air in system.
2. High pressure leaks - external.
Published 10-21-2010, Control# 198-04
REMEDY
1. Any cause under NO BRAKES.
1. Repair or replace.
2. Replace.
3. Check all circuit lines, hoses and
fittings. Tighten or replace.
4. Perform leakage test.
5. Replace pump.
charging 6. Replace valve.
1. Replace brake discs. See Section
6.
2. Perform leakage test. Repair or
replace. See Section 7.
1. Bleed brake system.
2. Apply full brake pressure, inspect
for leakage in lines, hoses and
fittings.
FIGURE 9-31
9
9-19