Hot breaks on M35A1

[knissen]

Hi all,
A few days ago I had the brakes adjusted in a workshop and checked.... everything seemed fine.
I was then out driving my M35A1 today - and the breaks got very hot, and ended up stuck! (as I stopped to check) I cooled them down, and loosened and drove to a workshop, with great mechanics who again cooled the brakes down, loosened the brake shoes and tested - everything worked fine... they moved freely, and were still able to brake the truck.
I then drove on, but again heated up the brakes, all six of them. I had the truck brought home on a flatbed.

My question is: What is the root course for this fault, wrongly adjusted brakes? dirty / rusty brake assemblies that makes it impossible for the brake shoes to disengage after braking, system building up pressure in the brakeline continiously (I dont know how?) or some other fault?
Any suggestion before I start to disassemble the brakes?

 

[gimpyrobb]

First I would have said something is out of adjustment, but all 6!? Have you checked the return spring on the peddle? I have seen these break or stretch allowing the peddle to bounce up and down and energize the system.

 

[WillWagner]

No freeplay in the brake pedal, a plugged M/C vent hole..

 

[knissen]

Thank for the fast replies! All suggestions seems more likely than 6 wrongly adjusted brakes - that works when testing.

 

[54reo]

Re: RE: Hot breaks on M35A1

No freeplay in the brake pedal, a plugged M/C vent hole..

Agreed, check for free play/clearance in the master cylinder adjustable pushrod. Should be 1/2" (at the pedal) free play prior to any master cylinder piston movement.

 

[Floridianson]

Have you been oiling airpack?

 

[tjcouch]

I had the same problem - it was the airpack. If you open the "glad hand" on the driver side of the truck, and air comes out when the service brakes are NOT applied, you can chalk it up to the airpack sticking.

 

[knissen]

Thanks again for great inputs.. I wish everybody a perfect weekend with lots of MV activities

 

[Floridianson]

We will expect a full repair report by monday.