Geico266

I'm having problems with my rear brakes vibrating and "pulsing" when they get hot ever since I put the GM wheel cylinders on. The brake shoes are cracked from the heat. Any ideas on how to tame them down? Can I switch the rear drums and see if that helps?

I could try replacing the brake shoes and not adjusting the brakes so "tight" and leave them a little more loose than I did.

Any thoughts?

P.O.R.

i'am having similar problem,pulsing/vibrating when breaks are being used heavy,i was thinking of not adjusting them up so much to see if that helps after i replace shoes,also looking for other ideas.

Geico266

Well, I swapped drums left to right & backed off the star wheel a full turn on each side. Seems to have helped with the pulsing and the brake peddle goes down alittle more before the brakes work. We'll see if this helps after a hard day of city driving.

Got Smoke?

Keep this up to date fella's.......I was considering swapping my wheel cylinders here soon......now I'm leary.

AlpineRAM

Hmm, do your trucks have the load sensor for the rear brakes? If they have you could try to adjust it a little to get a little less bias to the rear.
If the drums are out of round they are out of round. Get them turned (if still possible) and remedy the cause.

Just my 2c

AlpineRAM

P.O.R.

i don't have a load sensor on my truck, i think my drums are the problem, out of round.i 'am going to replace the shoes and drums and not adjust them up so much.hope thats the answer because i sure like having some stoping power.

infidel

I highly doubt the larger cylinders are the cause of the problem. I've had them on both my trucks over three years and 100k.
Several friends most of whom tow heavy have been using the larger cylinders for just as long or longer without a problem.

I've seen the problem Geico speaks of come from worn axle bearings that allow the entire hub to move laterally. It doesn't take much.

northslope

IHMO it can be difficult to properly adjust the brakes simply because of the drag of your limited slip (especially with a dually). I adjusted one side then the other side, but by the time I adjusted the other side it was way too tight couldn't feel how much drag there was. Almost had a fire it was really somethin! Found that If you jack up one side reeeeaaalllly high (to prevent gear oil from puking all over) unbolt the axle shaft then adjust you will get a muuuuucccchhhh more accurate adjustment. As for your warped drums, they'll not heal themselves with time but will either need to be machined or replaced, they tend not to "true" themselves, have to turn mine too someday!



PS - THE LARGE BORES ARE THE ONLY WAY TO GO I was just a when adjusting my brakes

johnh

it`s pretty hard to outwit the engineers unless you are one

Haulin_in_Dixie

Backing off on the adjustment does nothing except give you a lower pedal.

northslope

Some Mopar models for the past 15 or so years have had hydraulic mis-matches resulting in warped front rotors due to excess heat due fully to lack of the rear brake function. So yes the "engineers" DID boff up the job and DID use the WRONG part for the job making the bores too small requiring too much hydraulic FORCE for the REAR brakes to FUNCTION properly. I mean come on just because someone is an engineer doesn't mean they're not infallible and that a simple gear head doesn't have a better way to do it! WE ALL have said stupid engineers! so yes ENGINEERS I believe can and have been easily outwitted on many occasions.

PS no offense intended or implied to any engineer just wonder what the heck they're thinking or not thinking of sometimes

Haulin_in_Dixie

Yes, must be true, but are we talking about the same engineers that gave us the VP44 and lift pump situation?

Geico266

It also determines when the rear brakes are engaging the drums relative to the front disc brakes engaging. The master cylinder is actually two systems in one, front and rear. If one system fails or leaks you still have (hopefully) brakes. Right?

Geico266

I swapped drums and backed off the adjustment. After 100 miles so far so good.

P.O.R.

sounds good,keep us posted