1523.6-0000010 OM
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6.9 Possible failures of trailer brake hydraulic actuator and guidelines for
troubleshooting
List of possible failures of trailer brake hydraulic actuator and guidelines for trouble-
shooting are given in table 6.9.1.
Table 6.9.1
Failure,
external manifestations, cause
Troubleshooting
Inefficient braking of trailer along with inefficient operation of service brakes
Presence of air in the hydraulic brake
control system
Bleed the hydraulic system with brake fluid
Hydraulic brake fluid shortage in hy-
draulic brake control system tanks
Bring brake fluid in the main cylinder reservoirs to
the required level, then bleed the hydraulic system
with brake fluid
Brake fluid leakage in junctions or
pipelines in the hydraulic drive sys-
tem. Air inflow into the hydraulic brake
control system
Tighten up junctions, replace damaged parts, then
bleed the hydraulic system with brake fluid
Clogging of the opening in main cylin-
der tank fitting, causing depression in
main cylinder, as a result of which air
leaks into the cylinder through seal-
ings
Unclog the opening. Then bleed the hydraulic sys-
tem with brake fluid
Clogging of pipelines of the hydraulic
drive system due to dent or contami-
nation
Replace pipelines. Then bleed the hydraulic system
with brake fluid
Insufficient brake pedal travel or the
pedal strikes against the cab wall
Adjust the clearance between the piston and the
main cylinder piston follower
Faulty adjustment of service brake
actuator
Adjust the service brake actuator
Inefficient braking of trailer along with poor operation of hydraulic link linkage.
Service brakes function well
Loss of pump performance
Replace the pump
Low level of oil in HLL tank
Add oil up to a required level
Oil leakage in junctions or high-
pressure hose of hydraulic drive sys-
tem
Tighten the junctions, replace worn out parts
Inefficiency of trailer braking. HLL and service brakes function well
Brake valve is faulty
Replace the brake valve
Trailer brake system is faulty
Repair a failure in trailer brake system
Trailer brakes are not released
Oil pressure in hydraulic control line
exceeds 0 MPa with pedals released
Replace the brake valve
Trailer brake system is faulty
Repair a failure in the trailer brake system