Brake drag left front

LennieM

Original poster
Member
Jan 2, 2012
28
Ok many years since i been here now, must be the TB running good
But now i have a strange problem i can't figure myself...
My left front brake drags after a few stops and can't get it fixed tryed new pads and lubed everything up but no improvement, changed the brake hose that fixed nothing....
Surely its the caliper i thought and got a used one and replaced but still the same.
Tryed lifting the car up and can barely spin the wheel opened the bleeder but no pressure in the line so it must be mechanical and not a hydraulic failure?
When the rotor gets hot i can feel in the steeringwheel that the rotor is warped, can this cause dragging brakes?
I have ordered new rotors and pads but does not feel right to put them on until the dragging is fixed , so anyone have any idea's?
 

xavierny25

Member
Mar 16, 2014
6,323
Staten Island, N.Y
I'd try a NEW caliper or a rebuild kit. Did you flush out all your old brake fluid? Also did you check the guild pins?
 

LennieM

Original poster
Member
Jan 2, 2012
28
yes flushed With new Oil, guidepins are smooth and wellworking.
I found on eBay new/rebuilt calipers for $250 for all 4 (thats the price the dealer here in sweden takes for 1 caliper) so have given that some thought...
Is there an issue with the Pistons in the caliper with them wearing because they are in some composite material?
Now older jeeps have a LOT of problems with that
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
AFAIK, ours are not composite but there have been instances of seizing pistons.
 

LennieM

Original poster
Member
Jan 2, 2012
28
Ok are you sure? A Quick Google on phenolic trailblazer it says we do?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I'm just going with what I saw on the outside, which seems to be metal but the piston itself seems to be phenolic. No matter the material, pistons do seize.
 
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gmcman

Member
Dec 12, 2011
4,656
Very likely your brake hose has collapsed on the inside, this will restrict fluid leaving the caliper since it will be under less pressure than when the brakes are applied, this will not be visible on the outside.

Brake hoses need to be replaced in pairs, not a hard job but a line wrench will make the job easier.
 

mrrsm

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LennieM

Original poster
Member
Jan 2, 2012
28
Ok thank you for all the replys!
Like said brakehose was replaced and opening the bleeder screw does not release the brakes. This makes me belive that either the pads or the Pistons or caliper it self binds, but everything runs smoothly when checking and the pads are nice and loose in the guides. Pins are lubed and moves like they are expected to.
I Will problably replace the calipers all around the car and hope this will solve the problem but i would really want to know what caused the problem for my own knowledge.
New discs, calipers pads and hoses and hopefully the problem goes away.
 
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LennieM

Original poster
Member
Jan 2, 2012
28
Ok, i talked to a mechanic at My local gm dealer today.
And he said it was very common problem with these type of calipers and he would never replace with a used caliper.
My car has been running 260000km now so maybe the calipers should be replaced all around anyways....
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Maybe but mine is approaching 290k km and still originals (unless they were replaced prior to me)
 

LennieM

Original poster
Member
Jan 2, 2012
28
Ok did another little test today had a thought about IF the pistons lost its shape i figured turning them a 1/4 turn would fix it until My calipers arrive. But nothing different.
Used my IR termometer and left front after testdtive is about 250'c and right about 130'c and same for the rear...
 

LennieM

Original poster
Member
Jan 2, 2012
28
Ok time for a little update got some time work on the brakes today, change rotors, pads, mounting hardware and calipers in the front and guess what!!!
Same issue as before left brake dragging!!!!
Im about to give up now can't seem to figure this one out.
My only Idea is that the caliper is not parallel with the disc but what would cause this the mounting bracket is new as well
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Maybe it's the master cylinder not pushing the same pressure on both sides.
 

LennieM

Original poster
Member
Jan 2, 2012
28
Well in that case would not opening the bleeder or the brakehose free the caliper. It does not
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Thought you said you swapped the calipers?
 

freddyboy61

Member
Dec 4, 2011
276
Just a crazy thought, have you tried spinning the hub with the caliper off. If it still binds, then maybe your hub is bad.
 

LennieM

Original poster
Member
Jan 2, 2012
28
Yes the hub is free and if i am to remove the caliper from the pads the lower piston is the one that does not return properly but i simply dont belive that 3 calipers act exactly the same. 1 org 1 used 1new.
Going to do a test with the caliper not attached to the car and use some metall to simulate the pads and rotor to see if it releases when hanging free. Seem like a good plan?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I'd use a block of wood but sounds like a plan.
 
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LennieM

Original poster
Member
Jan 2, 2012
28
Well googling a lot tonight and brake caliper missalignment can cause drag i have changed a wheelhub right before getting these problems when i think about it...
Perhaps the hub was not machined correct and causes the rotor to not be square to the caliper?
Seems like i have some work cut out for me tomorow too them :smile:
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Maybe the hub mating surface is rusted or something. I've seen that happen with a brake disc and hub surface.
 

LennieM

Original poster
Member
Jan 2, 2012
28
Well it seems like the caliper does not retract as well as i hoped if i use a metal block between the caliper it still holds on but not so much that i cant remove it but still a little problably enough to cause a drag.
Should not the rotor push it back since no rotor/hub is completley witout any wobble?
I checked with an indicator gauge and it showed 0,02mm!!! Thats amazing!
So i them made a schims 0,05mm and now i got about 0,2mm wobble and took it for a drive and braked a few hard stops and a few light brakings and headed back and the rotor is the same or actually a few degrees colder than the right...
Could this be it?!
Should the rotor help pushing back the Pistons ?!
On all other cars i have worked on the square seal pushes the piston back.
 

LennieM

Original poster
Member
Jan 2, 2012
28
Oops, read the thread above and saw that Max lateral runout was 0.05mm.
Then have way to much now but now its working...
 

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