sww943

we have a solution to the problem, one of the relay valves was hanging, the replacement part was just as bad as the origional, i used a less costly overseas brand and the tolerences were to tight inside for proper travel. lesson learned, thanks for all the ideas

evening, ended the day where we have started, both quick release valves are replaced, both of the relay valves are replaced( square boxes with 5-6 ports). removed the slack adjuster from the clevis and backed off, the s cam moves freely and is well greased, the rear chambers will retract once all air pressure is out of the system and you refill the system to normal pressure, release the parking brake and it retracts in, mash on the foot valve and it stays outward, im guessing now it is in the foot valve?? thanks

thanks for the advice men, i have replaced the quick release valves and the rear relay valve, the brake chambers are almost new with excellant linings, i even lubed the foot valve- not removed and same old prob, with back axle, when drain the air system then rebuild it with air, and release the in cab parking brake, the chambers retract, then after depressing the foot brake, the back chambers stay in the extended position. im not really sure what to try next???? scott

yes i hear a gush of air and the parking brakes work instantly,

hello, i have a 93 ch, the back axle chambers are very slow to release when applying the foot pedal, the front rear axle chambers work as they should, any ideas before i replace parts needlessly thanks sww