Operation and maintenance manual

Section 250-0000
SM 2155 Rev 1 10-03
5
BRAKING SYSTEM DIAGNOSIS
CONDITION REASON REMEDY
Inadequate braking Low System Pressure Check oil level
Check oil condition
Check for leakage
Check system pressure and adjust as
required
Treadle valve delivery pressure below Check front and rear brake circuits
normal Check treadle valve operation
Check for leakage (modular assembly)
Brake surfaces inefficient Check friction disc wear
Check brake packs for leakage
Replace seals or components as required
Brakes do not release Defective treadle valve Repair or replace defective components
Check adjustments (pedal return)
Loose or broken wire in brake manifold Repair circuit as required
valve circuit
Faulty solenoid Replace defective component
Faulty park/emergency switch Repair or replace as required
Restriction in tank return line Clear restriction
Seal bypass condition - parking brake Replace seals or component as required
assembly
Parking brake does Faulty park/emergency switch Repair or replace as required
Faulty solenoid Replace defective component
Faulty park brake assembly Replace seals or component as required
Blocked orificed check valve in brake Clean or replace orificed check valve
manifold valve
Faulty brake manifold valve Check brake manifold valve operation.
Repair or replace valve as required
Emergency brakes do Faulty park/emergency switch Repair or replace as required
Faulty solenoid Replace defective component
No transmission pilot pressure at Check transmission pressure
directional control valve Check for restriction in pilot line
Faulty directional control valve Check spool operation. Repair or replace
valve as required
Oil leakage - service brakes Check and repair
Faulty park brake assembly Replace seals or component as required
Faulty brake manifold valve Check brake manifold valve operation.
Repair or replace valve as required.
Faulty priority unloader valve Check priority unloader valve operation.
Refer to Section 250-0075, PRIORITY
UNLOADER VALVE.
Braking System - Braking System Schematic
not apply
not apply