It is a very good idea to check brake temps periodically as you might save some big bucks by catching a problem before serious damage. This has been discussed many times before, but here is an example of what can be found. Coming back from my first job this morning I noticed my left rear driver drum was 288 deg. and the other drums were 110 deg. I found the problem and only had to replace a seal that over heating had caused it to be suspect and a spring. The shoes were still good. A spring had broken in the brake can and the brake was dragging. Total cost spring $2.69 seal $42.00 labor nothing. I am posting it even though it isn't a Foretravel , as it could just as easily happen to a coach.
The big difference here is the watchful eye of an owner
over an employee that might have not have done anything.
Glad you caught it before it failed a smoke test.
Carter-
Just want to be sure I understand what happened here.
Is this correct: the broken spring is the one that applies pressure to the brake shoes when you set the "parking brake". When you are driving, air pressure
normally compresses the spring, taking the spring pressure off the brake shoes. When the spring broke, the broken piece interfered with the normal retraction movement of the rod inside the canister, causing the brake shoes to drag.
Do I have that (approximately) correct?
You are kind of correct. There is a spring you are correctly describing however the one in the picture is a separate spring in the other half. The spring in the picture is right where the pushrod comes out. It is a return spring the retract the pushrod when the brakes are released. They aren't very strong to start with.
OK - I think I got it. The return spring broke, so it did not have sufficient strength to retract the shoes, so they were dragging.
Thanks! ^.^d
Yes this is a return spring in addition to the spring on the shoes. Besides dragging, the pieces can jam the piston from applying the brakes too. This would be very important on my coach as it is the only spring to pull the slack adjuster rod back. That axle on my truck does not have a maxi on it. The front driver axle has the parking brake. If I had ordered the truck new it would have had maxi's on both drive axles.