Brake lock up and pedal gets too hard and front rotors gets red hot while driving

Tiny
MICHAELAMOHAFORO
  • MEMBER
  • 2014 CHEVROLET SONIC
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 72,000 MILES
I have the car listed above LT model. The brakes get stuck and pedal gets too hard while driving till the car can no longer move and the Traction light come on. The front rotors gets red hot and can I smell the scent of burning brakes and also see the smoke from the from wheel. It releases after about an hour when the engine is turned off. I changed the front calipers and the drum cylinder but this did not help. Please help!
Wednesday, January 15th, 2020 AT 10:13 AM

5 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,754 POSTS
When this only happens to one front brake, the best suspect is a constricted rubber flex hose, but to have that happen on both sides at the same time isn't very likely. To identify that, the only way to make that brake release right away is to crawl underneath and open the bleeder screw on that caliper. That will let the trapped pressurized brake fluid escape.

When this affects both front wheels at the same time, it is usually due to the brake fluid was contaminated with a petroleum product. That can include engine oil, transmission fluid, power steering fluid, axle grease, and penetrating oil. Those fluids are not compatible with the rubber used for parts that contact brake fluid. They'll cause the rubber parts to swell, and most commonly it's the rubber lip seals in the master cylinder that grow past the fluid return ports to the reservoir and block them. The trapped brake fluid keeps the brakes applied slightly, and the constant friction generates heat. That heat migrates into the brake fluid where it expands, and since it can't release back into the reservoir, it applies the brakes even harder, and that generates more heat. This keeps on building as long as you force the car to keep moving.

The way to identify the brake fluid is being trapped by the master cylinder is to loosen the steel lines where they attach to it. If that lets the brakes release, the repair is an expensive one. The only proper solution is to remove every part that contains rubber that contacts the brake fluid, flush and dry the steel lines, then install all new parts. That includes the master cylinder, calipers (again), wheel cylinders, rubber flex hoses, and the combination valve that sits on the frame right under the master cylinder. If the replacement master cylinder doesn't come with a new reservoir and / or caps, the rubber bladder seals under the caps must be replaced too. If the car has anti-lock brakes, which yours does since traction control is an added-on option to the ABS system, the hydraulic controller must also be replaced because it has rubber seals and o-rings inside it. If any rubber part is not replaced, the contamination will leach out of it and recontaminate the new brake fluid and new parts.

This problem can also be caused on many car models by the brake light switch being out of adjustment. If it holds the brake pedal down a little, that will also keep the brake fluid trapped, and it will build pressure the same way. To identify this as the cause, loosen the nuts holding the master cylinder the power brake booster, then pull it forward 1/8th inch or more. If that lets the brakes release, it is not the seals in the master cylinder that are trapping the brake fluid. It is simply that the brake pedal is not being allowed to return fully.
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Wednesday, January 15th, 2020 AT 12:30 PM
Tiny
MICHAELAMOHAFORO
  • MEMBER
  • 3 POSTS
I will try doing this the next time the brake lock up and will update you on that.
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Wednesday, January 15th, 2020 AT 12:56 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,754 POSTS
That will be wonderful. We like to know what the final solution is. Let me know too if you have more questions. You can also find many related articles here:

https://www.2carpros.com/articles

and here:

https://www.youtube.com/user/2carpros/playlists
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Wednesday, January 15th, 2020 AT 2:32 PM
Tiny
MICHAELAMOHAFORO
  • MEMBER
  • 3 POSTS
So, this morning the brakes got stuck whiles driving. I tried using your first suggested solution by opening the driver side of the bleed screw and it immediately released. About 5 miles on on the road the brake was stuck again. This time I lost the passenger side of the bleed and I could hear the pistons released and was able to drive afterwards.

I will change the brake hose and monitor it to see if it will stuck again. I will keep you posted.
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Sunday, January 19th, 2020 AT 10:46 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,754 POSTS
Hold on. It isn't likely there's two separate problems. Before you go through the trouble of replacing hoses, all we know so far is the brake fluid is being trapped and is building heat and pressure. We don't know where it's being trapped.

The next step is when the brakes lock up, loosen the lines right at the master cylinder. If that lets the brakes release, it can only be the master cylinder that is causing it, and that is likely caused by contaminated brake fluid. If they don't release, the blockage is further down the line.
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Sunday, January 19th, 2020 AT 1:14 PM

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