Brake problems 1999 s10 zr2

[litl red]

Had great help from you folks before, and looking for ideas again!
1999 Chevy S10, ZR2, 4.3 engine...apx. 140,000 miles. 4WD

Had my front brakes replaced last fall~mechanic replaced both rotors, pads and one side on the ABS sensor that had been damaged. Brakes worked great. Calipers seemed fine.

A couple weeks ago started noticing noise in the rear brakes and knew it was time to replace those.

My mechanic replaced both rotors on the rear and one set of calipers along with brake fluid line. We bled the brakes, but the new caliper locked up. We bled them again and got the caliper working, then the other caliper locked up. We wound up replacing both rear calipers with new ones as well as new brake fluid lines.

We'd bleed the brakes, but it didn't seem like we were getting much for brake fluid to the rear. Pedal seemed a little softer than before, but the rear calipers were working.

No ABS or brakes lights have ever come on.

Haven't driven the truck much, but yesterday we went to town...and after a brief stop, the brake calipers locked again. I had to get the truck home, so we could only drive it about 20mph. (fortunately didn't have to go far)

Do we need to try replacing the front calipers too?
Thanks for any and all ideas: hoping its just something we overlooked.

[MT-2500]

Originally Posted by litl red

Had great help from you folks before, and looking for ideas again!
1999 Chevy S10, ZR2, 4.3 engine...apx. 140,000 miles. 4WD

Had my front brakes replaced last fall~mechanic replaced both rotors, pads and one side on the ABS sensor that had been damaged. Brakes worked great. Calipers seemed fine.

A couple weeks ago started noticing noise in the rear brakes and knew it was time to replace those.

My mechanic replaced both rotors on the rear and one set of calipers along with brake fluid line. We bled the brakes, but the new caliper locked up. We bled them again and got the caliper working, then the other caliper locked up. We wound up replacing both rear calipers with new ones as well as new brake fluid lines.

We'd bleed the brakes, but it didn't seem like we were getting much for brake fluid to the rear. Pedal seemed a little softer than before, but the rear calipers were working.

No ABS or brakes lights have ever come on.

Haven't driven the truck much, but yesterday we went to town...and after a brief stop, the brake calipers locked again. I had to get the truck home, so we could only drive it about 20mph. (fortunately didn't have to go far)

Do we need to try replacing the front calipers too?
Thanks for any and all ideas: hoping its just something we overlooked.

You need to find out why calipers are locking up.

When they are locked open bleeder screw and see if that releases them.

Post back what that does.

On bleeding abs brakes a ABS capable scanner is needed to bleed the right.

[Airjer_]

Are you sure its not the ebrake hanging up in the rear?

[litl red]

We did check the emergency brake and it seems to be functioning just fine. When the rear brakes were first replaced, it would pump fluid back fine the first couple times of bleeding...then it would not bleed any more.

After repeated attempts, it seemed to finally be bleeding.
I am wondering about needing to flush the brake fluid out and replacing it.

The next day after the brakes were locked, I went out to check on it and they were all released and working fine. I didn't have time to take it out for a run....and am planning on that tonight or tomorrow.

The mechanic is concerned it involves the ABS module and tells me that the valve can't be replaced...but the whole unit has to be replaced (and I understand that it is quite costly)

I'll ask him if the calipers released when he opened the bleeder screw and will post his answer asap.
THANKS very much for the quick replies!!

[litl red]

We did check the emergency brake and it seems to be functioning just fine. When the rear brakes were first replaced, it would pump fluid back fine the first couple times of bleeding...then it would not bleed any more.

After repeated attempts, it seemed to finally be bleeding.
I am wondering about needing to flush the brake fluid out and replacing it.

The next day after the brakes were locked, I went out to check on it and they were all released and working fine. I didn't have time to take it out for a run....and am planning on that tonight or tomorrow.

The mechanic is concerned it involves the ABS module and tells me that the valve can't be replaced...but the whole unit has to be replaced (and I understand that it is quite costly)

I'll ask him if the calipers released when he opened the bleeder screw and will post his answer asap.
THANKS very much for the quick replies!!

[litl red]

Sorry it took awhile for me to get a chance to work on the truck again. OK. Front brakes are locked up. My husband got in the truck, pumped the brake 3 times and held it while I bled the brake. Did this 4 times on each side (front wheels). The fluid was nice and clear and didn't appear to have any bubbles or gunk.

He said that when he was holding the brake down and I opened the bleeder valve, the brake light would come on. When I closed the valve and he touched the brake pedal...the light would go off immediately. Same thing on both wheels.

The wheels will not turn freely after bleeding. Seems like the right front is a little harder than the left side to forcibly turn.

I did check the rear calipers (newly replaced) and they work fine.

Should I remove the front calipers and compress the cylinder to see if it will reset? I am desperate for ideas since I've been in a borrowed vehicle for over a month now and really am needing the farm truck! I don't have a lot of resources to keep throwing parts at it if it is something simple.

Thanks in advance for any help anyone can provide. this is a head scratcher....the front calipers were working just fine...then to have them suddenly seize up after replacing all the brake parts on the rear seems really wierd!

[MT-2500]

Originally Posted by litl red

Sorry it took awhile for me to get a chance to work on the truck again. OK. Front brakes are locked up. My husband got in the truck, pumped the brake 3 times and held it while I bled the brake. Did this 4 times on each side (front wheels). The fluid was nice and clear and didn't appear to have any bubbles or gunk.

He said that when he was holding the brake down and I opened the bleeder valve, the brake light would come on. When I closed the valve and he touched the brake pedal...the light would go off immediately. Same thing on both wheels.

The wheels will not turn freely after bleeding. Seems like the right front is a little harder than the left side to forcibly turn.

I did check the rear calipers (newly replaced) and they work fine.

Should I remove the front calipers and compress the cylinder to see if it will reset? I am desperate for ideas since I've been in a borrowed vehicle for over a month now and really am needing the farm truck! I don't have a lot of resources to keep throwing parts at it if it is something simple.

Thanks in advance for any help anyone can provide. this is a head scratcher....the front calipers were working just fine...then to have them suddenly seize up after replacing all the brake parts on the rear seems really wierd!

As in post 2 did you open bleeder to see if wheel releases.
If so your brake system is holding pressure on it.
Check brake hose for clasped hose.
To check brake hose for holding pressure on caliper crack line where it goes into it.
If it releases it there the brake system is holding pressure on it.
If hose good check master cylinder or abs for holding pressure on it.
If not check caliper for sticking on and check sliding pins for sticking.