Midland SIDE DUMP GRAVEL TRAILER Operator's Manual page 98

PROBLEM
Air System (cont'd)
Poor braking performance
(cont'd).
86
CAUSE
Full function valve (FFV) leaks
at exhaust port with all brakes
released.
Full function valve (FFV) leaks at
exhaust port with service brakes
applied.
Spring parking brake (service
only service chamber side of
spring brake) drags or won't
release.
Spring parking brake (service
only service chamber side
of spring brake) leaks when
pressurized for park brake
release.
SOLUTION
Replace FFV valve.
Replace FFV valve.
Check for:
- Improper adjustment, restriction
or broken line.
- Diaphragm failure.
- System pressure too low (120 psi
min).
- Improper manual release.
- Broken return spring (spring
side).
- Broken power spring.
- Replace entire unit or piggy-back
emergency section.
Check for:
- Ruptured spring side diaphragm.
- Hose leaks.