brake question

leadfoot33 · Jul 4, 2011

okay guys, i am having problems with the rear drum brakes on my 99 classic 1500 chevy. i knew the old drums and brakes were shot so i reaplaced them, still have abit of a pedal pulse (assumiong front ones as you can feel it in the steering) but heres the problem, after i replaced the shoes and drunms and got new return spring kits on both sides, the shoes seem to adjust them self out to the point that they are dragging and you can really fell them grab. i dont know what it is, had the drum deglazed and checked for being round, they are within tolerances but it feels like they grab and let go grab and let go. i am going to try bleeding the brakes tomorrow and backing them off again. anything else i am missing here?
thanks sorry for long post.

kbrunlees · Jul 4, 2011

most rear drum breaks have a star wheel that has a ratchet lever that will cause the drums to adjust every time you back up. If the ratchet is not free wheeling( you just sand it don't oil it) then it won't tighten it up. Is it possible that one of the keepers that holds the shoe in place has come loose? that will cause it to drag, and wear out the parts real quick. The self adjusters will only tighten up to the point where the shoe is just barely touching the drum and no more when relaxed and then engage the drum when you brake. If it is over tightening I suspect you may have the wrong part( just a possibility). Ususally chevies are pretty good with their part matchups.

leadfoot33 · Jul 4, 2011

ya i just got back inside form bleeding the brakes, no air in there. everything appears to be right. i took it to a mechanic last week cuz i was lost and they put a new spring kit in it and said there ya go but when i drove it away they left it a little to tight so backed it off and it was good for a while so i will check again today and see how it goes. but everything appears to be correct hmmm

growly · Jul 5, 2011

Did you get the primary and secondary shoe on the right side?

leadfoot33 · Jul 5, 2011

you betcha i even had a mechanic take it apart and check it all out as well. (they installed the new spring kit)
short lining on the front and longer on the back. i have double checked and trippled checked all the parts so i am just wondering if maybe its holding pressure in the lines and not relieving is that possible?

leadfoot33 · Jul 7, 2011

another quick little note for ya. been about 230km since i backed them off. still good. but i still get pedal pulsing and truck jumping a bit. but also noticed that every once in a while (2 times on my way home tonight) i get smooth proper braking. any ideas on that one?

kbrunlees · Jul 7, 2011

Check your tires you might have one that has tread separation. Causes all sorts of weird probs.

leadfoot33 · Jul 7, 2011

rears are good already checked that

but still doesnt explain why the brakes keep getting way to hot like they are adjusting out all the way

Summitric · Jul 8, 2011

The pulsating feeling you get when braking is either warped rotors or warped brake drums...... Do you feel the pulsation in the steering wheel at all? If so, then you have warped front rotors, and if not, then the rear drums are probably warped. They will need to be either machined or replaced, depending how much material is remaining..............................

leadfoot33 · Jul 8, 2011

rears are brand new drums and shoes. i am pretty sure the fronts are warped as well. (next on my list) just concerned about the rears tightening up too much all the time. its been good so far but i will keep an eye on it and will probably mark the threads to see if its still adjusting out.

growly · Jul 9, 2011

Had a truck a few years back that was overheating the rears after a complete brake job,i mean they were smoking!

After a lot of screwing around it ended up being the ABS module doing it,was holding pressure in the lines after the pedal was released.
Not sure if yours is the same set-up or not,has the box right under the master cyl.? Ended up just removing it and it was all good.

brian h · Jul 9, 2011

drums or rotors are the usually cause of brake pulse,do you feel it in the steering wheel? the abs sensors or module can cause this also

leadfoot33 · Jul 10, 2011

i thought about that and decided that when it acted up (yesterday) i would crack the bleeders and see if there was pressure in the lines but there wasnt so i dont think thats the problem, i am starting to lean towards a set of bad cut shoes. i didnt buy the gm ones just a jobber set. so thats what i am thinking.

youngpolarisguy · Jul 11, 2011

My dads chev 1500 seems to adjust the rears to the point they drag if you drive in reverse to much, but as for the pulsation i don't haw many jobber drums i have installed at the shop and almost all of them come back for some sort of issue( usually pulsation) go get a set of gm drums or find a good tech that can cut the jobber drums and see if that helps.

leadfoot33 · Jul 12, 2011

drums were measuerd for being warped by 2 different mechanics and they checked out so it must be a bad set of shoes i think. will probably change them later

Ancient Sledder · Jul 16, 2011

To check for out of round drums is simple. Find a road with no traffic and drive at 80-90 kph. Slowly apply the park brake and see if you have a vibration. There will be no shake if the drums are good. I have only run into one master cylinder that was holding too much pressure and wearing out the shoes. There is a valve on the drum side of the master that holds 5 PSI. Another problem I have run into is flex hoses damaged on the inside. This will give you a "valve" that will keep the pressure on. If your master cylinder pushrod is too long that should give you problems on all 4 wheels. Good luck.

brake question

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