Rear Brakes Pulsating

[sewlow]

Did they re-use the U-bolts? That's a No Beuno!
Which Co.'s flip kit was installed? I believe that most have the pinion angle correction built in, but you never know till that gets checked.

 

[Boulky12]

The rears should have some drag, but too much is not good. Creates heat which can warp the drums. PitA adjusting these as you have to remove the drum to make any adjustments.
Sure that the pulsating is not coming from the front rotors? The fronts do do most of the stopping & the ones on these trucks have a tendency to warp. Even the GM ones are el-cheapo off-shore crap nowadays.

I really dont think it's the front rotors. When I first got the truck(about 8 months ago) the rear brakes werent even getting brake fluid. It was only the fronts stopping, and she still stopped great. I really think its the rears cause she was all good until I took the wheels off, to put the notch in. And this pulsating is pretty significant so it would seem weird that the fronts got warped that bad, that quick.

While it's good that you had the drums turned (especially at no cost!), the problem did not go away. I assume it was not present before the frame C-Notch work? If it was not, and you did not work on the rear brakes, it has to be something to do with what you just worked on.

Is the rear axle mounted to the leafs exactly on 90 degrees to the frame. Measure from a reference point on each side to the axle housing. Is the axle rotated at all? Is it absolutely tightly fastened to the springs? Check everything that was taken out and replaced--maybe it's something simple.

To be honest Ironhead, before this started happening, and after I got the rear brakes working, there was always a very slight pulsating when hitting the brakes on the freeway at 70. But it was so minimal I didn't even feel it required attention. I can and will check all the things you mentioned but is it possible this is thinking wayyy too ouside the box, cause like I said earlier it was all good until I took the rear wheels off to put the notch in.

 

[Boulky12]

Did they re-use the U-bolts? That's a No Beuno!
Which Co.'s flip kit was installed? I believe that most have the pinion angle correction built in, but you never know till that gets checked.

The previous owner installed the flip kit, so I'm not sure if they reused the U-bolts, or which Co's flip kit it is. I feel they did a pretty solid job though because I've been frame banging everywhere until I put the notch in, and I'm sure the previous owner was too, and she's always drove straight as an arrow. I'm still feeling like this is something small to do with the rear brakes, but I'll check the pinion angle anyways. Thank you

 

[Boulky12]

Guys if you know you have pulsating coming from the rear brakes, check the damn adjustment for the drums!! Cause that's all it ended up being for me!!

I was on the edge of going to the store and buying all new drum hardware for both sides. My dad took the truck for a drive last night, he asked "have you tried adjusting them?"

So this morning I took wheel and drum off the driver's side, turned the adjuster so that brake shoes stuck out more and be tighter on the drum. Put the drum and wheel back on. I didn't even touch the passenger side cause I knew the driver's side was giving me the problem.

Went for a drive, and no more pulsating at all!!! Damn that was such a good feeling.

Hope this can help someone else out.

 

[sewlow]

The problem with the auto adjusters on these trucks is that the teeth on the wheel have such large steps, that by the time the adjuster actually works, the shoes have worn down to create the problem that you have just gone through.
Now I feel like the dumb-ass for not having thought about this sooner to point it out! I actually DID know this!!! Monkey muffins! DOH! Lol!
I don't rely on those adjusters! Cycling the E-brake a few times, which is supposed to work...doesn't!
Driving in reverse & then hammering the brakes, which is also supposed to ratchet up those adjusters, doesn't do it either!
To top it off, GM in their infinite wisdom, provided no windows on the back of the backing plates to be able to adjust the brakes without having to remove the wheels & the drums! SMH!
Disc-conversion, disc conversion, disc conversion!!! Just from a maintenance point of view, is the only answer!

 

[Boulky12]

The problem with the auto adjusters on these trucks is that the teeth on the wheel have such large steps, that by the time the adjuster actually works, the shoes have worn down to create the problem that you have just gone through.
Now I feel like the dumb-ass for not having thought about this sooner to point it out! I actually DID know this!!! Monkey muffins! DOH! Lol!
I don't rely on those adjusters! Cycling the E-brake a few times, which is supposed to work...doesn't!
Driving in reverse & then hammering the brakes, which is also supposed to ratchet up those adjusters, doesn't do it either!
To top it off, GM in their infinite wisdom, provided no windows on the back of the backing plates to be able to adjust the brakes without having to remove the wheels & the drums! SMH!
Disc-conversion, disc conversion, disc conversion!!! Just from a maintenance point of view, is the only answer!

Lol I was actually pretty surprised no one here mentioned the adjusters, but it's all good. And I was also surprised that you have to take the drum off to adjust. Everything else I've worked on I didnt have to. I feel like I've gained some good experience from this so I'll know what to do if I run into this again on other obs's.

Disc-conversion sounds pretty nice. I'm gonna look into that.

Thanks again!

 

[sewlow]

'92-'96 Impala SS or 9C1 are the ones to look for. It's a bolt-on conversion. And those rear diffs can be had with an Eaton posi, instead of the notorious gov-lock!
I've got this in my stash. No rotors though. But no prob. I'll be using ones from R1concepts to match the front ones I have now.

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An Impala rear dif. with the posi is in that stash, too! ('scuse the dog hair!)

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