Brakes lock up after driving approximately fifteen minutes

Tiny
BROKECAR789
  • MEMBER
  • 2002 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
They get so hot the smoke. I have changed all 4 calipers, rotors, brakes, flex brake line, master cylinder, brake booster, ABS module and pump. What more could it be? Everything is now brand new. Please help.
Friday, April 23rd, 2021 AT 4:18 PM

8 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Hi,

Is this happening at all 4 wheels? If it is, when the brakes are cool, check each wheel to see if there is a drag. A slight drag is normal, but you don't want it to be difficult to turn a wheel.

If there is a heavy drag, that will cause the brakes to heat, the brake fluid to expand, and slowly lock the brakes. So, since you have replaced nearly everything, something is still causing them to drag. If it is all wheels, make sure nothing is preventing the brake pedal from returning to the fully released position. If it is, then I want you to try something. When the brakes are hot and stuck, loosen the brake master cylinder to see if they all release.

If it is only one wheel, let me know that. Also, let me know if you properly cleaned the brake caliper mount, which holds the pads in place. I've seen rust cause them to prevent the pads from moving.

Let me know.

Joe
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Friday, April 23rd, 2021 AT 7:49 PM
Tiny
BROKECAR789
  • MEMBER
  • 4 POSTS
It's all 4 tires, but the front two are worse and smoke really bad.
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Friday, April 23rd, 2021 AT 7:51 PM
Tiny
BROKECAR789
  • MEMBER
  • 4 POSTS
Also road down the road and got it warmed up. And took the master cylinder lid off and it did not unlock the brakes.
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Friday, April 23rd, 2021 AT 8:06 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Hi,

Not the lid. LOL (sorry for the confusion) I need you to loosen the mounting bolts on the master cylinder (see pic 1 below). You don't have to remove them, simply loosen them approx 1/2". If there is something keeping pressure on the master cylinder all the time, loosening those bolts should release the pressure and release the brakes.

Let me know.

Joe
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+4
Friday, April 23rd, 2021 AT 9:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Hi,

I don't think the rod itself is adjustable. Check inside the vehicle where the brake light switch, push rod, and the brake pedal is connected to make sure the brake light switch isn't preventing the pedal from completely releasing.

Let me know.

Joe

See pic below.
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Friday, October 28th, 2022 AT 10:18 PM
Tiny
HONDAJIM
  • MEMBER
  • 9 POSTS
That’s not it It’s something to do with the rob I thinks. There is so much pressure that the car will not move till I lose the bolts that hold the mc to the booster. Crazy doesn't make any sense.
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Saturday, October 29th, 2022 AT 1:31 AM
Tiny
HONDAJIM
  • MEMBER
  • 9 POSTS
I took the whole brake switch out and still locked up.
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Saturday, October 29th, 2022 AT 2:09 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,513 POSTS
When it is locked up can you loosen the master cylinder mounting bolts and will it start turning? If so, the master is bad and needs to be replaced here is a video that shows how to bench bleed it.

https://youtu.be/WDxvEQrMkBg

Please go over this guide and report back.

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Sunday, October 30th, 2022 AT 4:06 PM

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