M35A3 pulsating brake pedal

[CanonNinja]

I'm kinda used to these quirks of these trucks now, but this one puzzles me. Last night my truck started getting a funny pedal feel, almost a pulsing. Normal braking, no noticeable fade, but the pedal will soften and harden and push back a bit under all braking, from light effort (for the A3) through panic stopping. Also smelling brake pads when at a complete stop.


Havent had a chance to PM the truck, but parking it, I checked all hubs for heat, parking brake, checked for fluid leaks at the back of the axles. Smell seems to come from rear but intermittently, never noticed any dragging while driving, no leaks noted, and only one hub was negligibly warmer than the others.


Whats the consensus here, where should I start besides the obvious easy things like brake fluid level check and/or flush?

 

[dmetalmiki]

That problem is caused by BRAKE adjustment (and OR a ( slightly)) "out of round" brake drum.
You can check the culprit by Jacking Each whel Then turning by hand, (where) you will Notice "grabbing" as you rotate the offending wheel. If a wheel was grabbing and getting hot , that can distort a brake drum exerbating the symptom/problem. Cure can adjustments or if too pronounced "skimming of the (offending) brake drums".

 

[73m819]

YEP what he said, OUT OF ROUND BRAKE DRUM

 

[CanonNinja]

awesome. never happened before last night, didnt think I could "warp" a drum that quickly, but I stand corrected. I havent really ever looked for replacement hubs/drums, but where/how much do they usually go for? Turning any brake parts means im just that much closer to replacing it.

 

[dmetalmiki]

WHOAHH!B4 buying new drums. After reading the relevent T.M.s. about "brake related problems" you may well work out That:
The brake/s out of or in TIGHT adjustment cause HEAT> Cause oil/grese Ingress to the drums.> Cause slipping or Grabbing of the Brake LINING > causes "hard/ normal" brake effort at the pedal!..So CHECK YOUR LININGS first..You may well find the offending drums extremly difficult to remove (for that inspection) and Neccesitates the "release of some of the adjustment" to enable removal for instpection. Then determine the "condition" of the shoes to determine >binding >slipping >brake pedel "effect". Read the TM.s thouroghly First.

 

[03silverado]

You could probably get a machine shop to turn them unless your hauling something heavy I wouldn't buy new unless I had to i would have them turned even if theyre a little big just driving around town shouldnt hurt them if you have to any truck supply shop should be able to get them I would think like fleet pride or what ever big truck parts place is near you