Rear Brakes Pulsating

[Boulky12]

I just got done installing a bolt in C-Notch in my 1990 C1500 single cab swb.

After I put the wheels back on and went for a test drive, I'm now getting a real bad pulsating on the pedal, when braking.

Can you guys give me some advice of what I should look for.

Ive had this issue before when I came back from the tire shop and got new rear tires, but it didn't feel this bad. I believe they tightened the lugs too much, cause all I did last time was take the wheels off, and put them back on.

I'd really appreciate the help. Thanks.

Good news is no more frame banging!


Here's some pics of my baby:

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[sewlow]

Did they install the rear wheels with an impact? (I see 'techs' do that & it makes my teeth hurt! Grrr!)
Don't believe what they say about their guns being 'calibrated' or that they used a 'torque-stick'.
Loosen them off & re-torque them with a proper torque wrench.
I take mine down to 60ft. lbs., then to 75 & finally down to 90. Makes a big difference!
If that doesn't cure the problem, get the drums turned. The nuts may have been tightened down so much that they warped the drums. May or not be permanent. Won't know until the drums are turning on the lathe & you go to hit them with that first cut. That'll tell you how out-of-round they are.

 

[Boulky12]

Did they install the rear wheels with an impact? (I see 'techs' do that & it makes my teeth hurt! Grrr!)
Don't believe what they say about their guns being 'calibrated' or that they used a 'torque-stick'.
Loosen them off & re-torque them with a proper torque wrench.
I take mine down to 60ft. lbs., then to 75 & finally down to 90. Makes a big difference!
If that doesn't cure the problem, get the drums turned. The nuts may have been tightened down so much that they warped the drums. May or not be permanent. Won't know until the drums are turning on the lathe & you go to hit them with that first cut. That'll tell you how out-of-round they are.

Yes they did tighten them down with an impact. I appreciate your advice. I'll torque them down just like you said when I get the chance.

About getting the drums turned. I dont have a lathe myself. Are the people at oriellys and autozone trustworthy enough to not **** them up. Or where else could I go.

 

[sewlow]

Pretty easy straight forward job. I started to do them for my ole man's cabs when I was around 12! Most of the chains do enough that they should know what they're doing.

 

[Boulky12]

Pretty easy straight forward job. I started to do them for my ole man's cabs when I was around 12! Most of the chains do enough that they should know what they're doing.

Cool. Thanks man

 

[Ironhead]

I'm going to assume that when you did the work on the frame, you took the wheels off the truck, but did NOT work on the brakes. If that's correct, the advice on torquing the lug nuts is great advice. I'd go just a bit further, by removing the drums, making sure that there is nothing on the studs to cause them to go on skewed. Then, I'd make sure the outside surface of the drums is totally clean, then do the same thing for the inside of the rims, where they go up to the drums. Then torque the lug nuts properly, and take the truck (looks good by the way) for a test drive. If you still have the pulsating, then it's time to have the drums checked for roundness, and have them turned or replaced if necessary.

Good luck on this.

 

[Boulky12]

I'm going to assume that when you did the work on the frame, you took the wheels off the truck, but did NOT work on the brakes. If that's correct, the advice on torquing the lug nuts is great advice. I'd go just a bit further, by removing the drums, making sure that there is nothing on the studs to cause them to go on skewed. Then, I'd make sure the outside surface of the drums is totally clean, then do the same thing for the inside of the rims, where they go up to the drums. Then torque the lug nuts properly, and take the truck (looks good by the way) for a test drive. If you still have the pulsating, then it's time to have the drums checked for roundness, and have them turned or replaced if necessary.

Good luck on this.

Yeah I did take the wheels off the truck, but did not do any work on the brakes when I put the C-notch in.

I torqued the lug nuts down properly today, took her for a drive, and she's still the same.

I'm gonna go ahead and get the drums resurfaced soon, and at the same time, check the studs and outside surface and inside of the rims, like you said.

And thanks for the compliment. I painted her myself for $40 with rustoleum flat black and rollers lol. Everybody that sees it in person can't believe I rolled it on.

Anyways I'll let you guys know what happens with the resurfaced drums. Thank you

 

[Boulky12]

So I took the drums to oriellys, they did a good job and made them look like brand new, and they let me go for free! Which was pretty badass. (usually 20 bucks a drum)

I got home, threw them on, put the wheels on, torqued the lugs down with the torque wrench, went for a test drive, and its still exactly the same

This is bullshit. What else could I check. Is it possible that this is being caused by the E-brake? I noticed one of the e-brake lines is wrapping around my C-notch with a little bit of tension.

Also I noticed when driving her, when i stick my head out the window, I can hear what sounds like dragging coming from the driver's rear wheel.

Would changing all the hardware holding the brake shoes help? Brake shoes have plenty of meat on them.

I'd really appreciate the help. Thanks

 

[sewlow]

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.

 

[Ironhead]

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.