Rear brake calipers will not fully release

Tiny
MCJR
  • MEMBER
  • 2002 CHEVROLET SUBURBAN
  • 91,000 MILES
After driving vehicle for a short time, both rear calipers will not fully release and have a drag on rotors. It will get worse as you drive until the rear brakes, rotors and rim are very hot and brakes are giving off a burning smell. I have duplicated issue and jacked up and find both rear tires hard to turn by hand, removed tires and removed caliper slide bolts and had to remove caliper from rotor by prying off with screw driver. After vehicle sits for 15-20 minutes, the pressure will relax.
Tuesday, June 5th, 2012 AT 3:34 PM

4 Replies

Tiny
MCJR
  • MEMBER
  • 3 POSTS
This happens when the brake booster push rod is adjusted out too far which does no allow the brake master to return fully holding the brakes on. To confirm the issue loosen the brake master mounting bolts 3 turns to see if the car starts to roll again, if so remove the master and adjust the booster push rod inward. Check the caliper slide pins have been removed and greased, there appears to be no crimped brake hoses. I am being told it could be the calipers, brake hoses, master cylinder, etc. How is the best way to trouble shoot this so I am not throwing parts at it?
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Tuesday, June 5th, 2012 AT 3:36 PM
Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
It is probably the pins. They are made for the caliper to move back and forth on and can get gummed up or bent. More than likely they just need cleaning and greasing.
Get some brake cleaner and some paper towel type shop towels and some high temp axle grease.
Clean the pins and the holes they travel in completely. Inspect for large bends then put a little grease on the o rings if applicable. See if the caliper will slide freely on the pins. If so, grease them up a little more, make sure they bottom out because too much grease will keep them from going all the way in.
Make sure dirt boots are in place and don't have tears. Check for movement againa and then install.
Test drive and check for operation.
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Tuesday, June 5th, 2012 AT 4:16 PM
Tiny
MCJR
  • MEMBER
  • 3 POSTS
Have already cleaned and greased the pins and holes they travel in. There is pressure on the rotors from the calipers unitil vehicle sits for a short period of time and then they free up again until you drive for a short period of time. So I checked the booster push rod and then adjusted it inward, fixed the problems thank you.
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Tuesday, June 5th, 2012 AT 5:04 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
That is great info. You are correct that this could be a hose issue but I think the theory is important to understand that the caliper is staying applied by either it sticking or the fluid is not being released.

I would suggest starting with removing the pressure from the caliper by opening the bleeder and if the caliper releases then the caliper is most likely being held by fluid pressure rather then being seized.

However, if it is not releasing then the caliper is seized and requires replacement.

https://www.2carpros.com/articles/brake-caliper-replacement

Below you will find the info on this depending on what the result is.

Please let us know if you have questions Thanks.
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Monday, March 15th, 2021 AT 4:18 PM

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