About two years ago while on a trip I had to have the piggyback changed on one of my rear brakes due to diaphragm rupture. This week I replaced the other original piggyback on the rear unit and replaced the rubber diaphragms on the two front brakes.
When I examined the rear brake's diaphragm it was clearly on its last legs. Large cracks had formed around the perimeter where it flexes the most. The two fronts were both in good shape, but being as old as they are I replaced them anyway.
if anyone has an older unit and you have not replaced at least the rear airbrake chambers I would strongly suggest you consider it. Age and road salts make them a ticking time bomb. They're not really difficult and not that expensive, but they will shut you down immediately if they go out while on the road.
SoCal Kevin
1995 HR Navigator
M11 400 Cummins
Allison HD 4060
Ready Brute Towbar; 2000 Suburban Toad
