thesheriff

I upgraded the rear wheel cylinders to the GM one-tons close to a year ago. For the last few months I have been noticing the brakes have been acting pretty funky. I can equate it to when the abs is going off. I decided to pull off the rear drums and saw brake fluid all over the hardware. This occured on both sides. The leak is definetly coming from both wheel cylinders. What gives? Is there anything I could have done to cause this? I have always had issues with front sticking calipers etc. Thanks for the help.

Hodge

The brakes acting up are probably because of the brake fluid on the shoes. As to the cylinders leaking- did the caps come off during assembly, etc.? Anything happen that would make you think it could leak? Otherwise, maybe you got a bad set of wheel cylinders.

Lary Ellis (Top)

Hmmmm I am having a hard time figuring out why new cylinders leaked so soon unless the rubber seals were old and rotten or perhaps the drums are extremely worn and the shoes as well with weak springs allowing the cylinders to extend so far they blow the seal......just thinking out loud here....

Did you replace all the brake fluid with fresh fluid when you did the brakes? No rusty or contaminated fluid?

thesheriff

I am having a hard time understanding the failure too. All the brake hardware looks great even the wheel cylinder seals. I have always had trouble with the front brakes but never the rear. There has only been one other occasion of one of the wheel cylinders leaking. However, this was after five years of doing the brakes. I also flushed the fluid this time around so the fluid is new. I am almost ready to get new backing plates but those babies are a little spendy.

oldblues

hi
how wer the brakes adjusted ?
were the shoes too far from the drum allowing cylinders too much travel so cups could come out of the bore ?
did salt water get in there and cause pitting?

thesheriff

Correct me if I am wrong but I thought the brakes were self adjusting? I went I reverse and slammed on the brakes so they would self adjust. I know on trailers with drums we usually manually adjust them with a spoon. It looks like the contact wear is the same around the drum on both sides. Luckily where we live salt is not an issue. I really should take them apart and get a really good look. If they are not self adjusting maybe the piston pushed too far out.

nickg

self adjusting they are susposed to be, but i've never seen a set work...

they need to be adjusted manually every 3months or when ever you do an oil change. if the are adjusted properly you can tell from inside the cab.
1 engine running
2. apply brakes (note pedal height to floor)
3. apply brakes again( note pedal height to floor)
4. repeat step 3 again
5. if you noticed the brake pedal seems to get higher(rises), your brakes are out of adjustment.
6 if there was no height change the brakes are adjusted properly.

to manually adjust brakes, the best method is to adjust till the wheel locks up then back off the brakes for proper drag, (you will need to push the self adjuster off the star weel to back the brakes off, )

I also find best results if you pull the axel bolts, so that when rotating the wheel your not turning the rest of the driveline at the same time, thus giving a better sense of brake drag

after doing a brake adjustment, go back and do the test in the cab again, if the pedal still rises, you will need to re-adjust the brakes again

thesheriff

You all are spot on. I did not adjust them manually and I doubt they adjusted on their own. This would make sense why they never really felt that great. I read about the big difference going to the GM cylinders but never saw much of a change. This would also explain the front brakes smoking off pads. Looks like I have some work to do!

infidel

For self adjusting to work the only important thing is to come to a complete stop in reverse without letting up on the pedal.
Going fast or slamming on the brakes doesn't add anything and in fact may make it harder/more uncomfortable to come to a complete stop.

After many years of manually adjusting thinking that the self adjustors weren't trustworthy I've found using the parking brake to come to a full stop in reverse every once in a while works very well.