COMMON BRAKE SERVO FAULTS
EXCESSIVE PEDAL TRAVEL
- External leak between master cylinder and servo or between servo and wheel cylinder
- Leakage past the rubber cup on servo valve operating piston
- Leak between servo push rod and push rod seal
GRABBING BRAKES
- Excessive friction between servo vacuum piston and vacuum shell
- Excessive friction between servo valve operating piston and body
HARD PEDAL
- Low vacuum from engine from collapsed, restricted or disconnected vacuum line from manifold
- Air valve or vacuum valve not seating properly
- Air leak past cup or seal on vacuum piston
- Faulty gasket under diaphragm or between slave cylinder and vacuum shell
- Blockage of breather slot in vacuum shell