Brakes are fucked up.
 

Ever since I put new shoes and drums on the rear of my truck, I have the awful Vibration when braking, especially from higher speeds.

I brought the drums back and got new ones, and the problem is still there.

The shoes are not on backwards or anything. One shoe has the pivot pin for the adjuster while the other does not.

The only thing I can think of is that somehow the shoes are fucked up.


Anyone have any ideas?

Re: Brakes are fucked up.
 

If a drum is warped it will cause the rate of braking to surge, for a given pedal effort. You'd feel pulsing through the pedal, and the surge, no vibration though. It's not uncommon with some el cheapo drums, they are meant to be turned before you use them for some stupid reason that makes no sense.

I don't think a shoe issue would cause a rotational vibration, at least not without visibly wearing them up in a pretty short time. None of that stuff rotates, you see.

I'd guess you lost a weight off of one of your wheels during the brake job. Try rotating the tires, see if the vibration moves around.

Re: Brakes are fucked up.
 

Maybe although I didn't find anything on the floor afterward.

The drums are Car Quest drums. The label on them says no finishing required. This is the 2nd set of drums and there is still a vibration. What are the odds that 2 different sets are fucked up?

I'll check the wheels out and see what's up with the weights.

Re: Brakes are fucked up.
 

On both sides the shoes have strange marks:

Attachment 16369
Attachment 16370


Could it be possible that something is fucked with the brake cylinder?

Re: Brakes are fucked up.
 

your brakepad was bonded, then cut with a hollow grind, in degrees, vs cutting one solid radius. stick some sandpaper inside your drum glue it down somehow, tension the shoes on the drum, then spin.

either that or the bond was walked on with a multi sided press roller, to promote faster wear-in to the drum face and just creased the lining.

i dunno. whats your measurements on the drum size?

Re: Brakes are fucked up.
 

IIRC, 297mm is the max diameter for turning on the drum.

Could I just carefully scuff them with some 80 grit by hand?

Re: Brakes are fucked up.
 

you need the radius of the drum to take the high spots off

Re: Brakes are fucked up.
 

in my experiance high speed shakes are normally front rotors, I dont find warped drums to really be bad at high speeds, usally slower stops. Those shoes are fine, they will brake in, no sand paper or glue needed. Can you feel the shake in your ass or steering wheel or brake pedal? You need to turn cheap drums because they pack 1000,000 of them in a container from chine and the wieght on them make them go out of round.

Re: Brakes are fucked up.
 

It is definitely the rear, because the front rotors and pads were the first thing I changed, and there were no issues at all for like a month or two until I got off my ass and did the did the drums. I can feel the truck shaking through the seat more. Nothing really in the steering. Not too much through the pedal. I've felt warped rotors through the pedal before, not really like that at all.

Re: Brakes are fucked up.
 

your drums are not centered to the hub, as in rotors are drilled wrong.

try rear drums for a 1500gmc shortbed, like a '90. iirc theyre 12" and not offset from the hub face like the longbed/tow package dealys

Re: Brakes are fucked up.
 

that does sound like rears :y

you know that the picture he posted is a toyota brake system right? :1

Re: Brakes are fucked up.
 

i would have the drums turned by someone who knows what they are doing, like a machine shop, you know the place the head that you sold me that ''had nothing wrong with it'' is gettin 3 bent valves and new guides installed at.


or maybe you should make sure the adjustment is good to go, say the new shoes for some reason doesn't stick out far enough and you aren't applying enough pressure to get a good, even clamping force which might cause vibration

Re: Brakes are fucked up.
 

same bolt pattern and approx depth. ive looked into this as theyre ribbed vents like gm likes to do vs solid.

Re: Brakes are fucked up.
 

I would either raplace those cheap shoes or sand the crap out of them. Make them look new again. You replace to parts and you have a bad vibration, and you have another set of drums and you still have the problem. I doubt you got another set of out of round drums even though they are probably cheap crap. I think its either your shoes or something you did putting them back in. Sand the ---- out of them. Sand them with a long piece of some rough grit sand paper like if you were shining a shoe (from end to end). Then rough up the drums again for break in. And how are you breaking in the brakes? I go 10mph then slow then 20 then slow, then 40, then slow then 50 then slow and so on if needed. YOu slow almost to a stop each time but dont totally stop. If they are bad again its you are the pads OR you need to kill the rear brakes all together by clamping them off on the hose part of the line then go brake on a safe road to make sure its not coming from the front.

PEACE!!!! :1

Re: Brakes are fucked up.
 

ill part out my '85 rear brakes to you. im going to part the truck

Re: Brakes are fucked up.
 

stop reading stoptech's breakin for disc brakes. Go back to H-T ::) Shoes willnot/ can not make a vibration.

Re: Brakes are fucked up.
 

Yes in a close minded brain your statement is true. Stuff has never surprised me with automotive. Think outside the box!!

Maybe he is not describing what is normally felt as a pulsation but more of a chatter or servere vibration. I think if he still has the problem he needs to clamp off the rear brakes and go test drive. THis will tell him if its coming out of the front or if he has a out of balance tire which he should feel anyways at higher speeds. Anyways sanding down the shoes is something simple he could try.

Re: Brakes are fucked up.
 

I average 12.5 hours flate rate a day and I couldn't agree with you more.

Re: Brakes are fucked up.
 

12.5? who do u work for?

Re: Brakes are fucked up.
 

flat rate... not actually hours spent working

Re: Brakes are fucked up.
 

sounds like a chev 1 ton i did rear shoes/wheel clys/drums on, i didnt drive it before hand :1, and got it all done and drove it down the road, felt like rear brakes for sure, was all frustrated, then used the ebrake to stop and no vibration... ive never ran into a problem with carquest stuff, id check your wheel cly's and just rought up the cerfice of the shoes, and clean everything off well with brake clean. i know you have done your front brakes but this truck had the same feeling. how are the front calipers? waring evenly? and are the rotors new or turned? whats the runout, thickness... just checking yo :6

Re: Brakes are fucked up.
 

I know it's the rears now, because I put the e-brake on going down the road, and the hard I pulled it the worse it got. I think I'm going to try cleaning the surfaces up.


Will you stop ------- crying? What more do you want for $90 shipped? I told you it ran when I pulled it. I wasn't about to tear it apart and inspect it myself, so I sold it cheap.


Don't part it. Fix it. They don't make them like that anymore.