Brakes locking up

Tiny
COBRAJET427
  • 2003 TOYOTA CAMRY
  • 105,000 MILES

Dealership talking about brake adjustment rod behind the master cylinder has been turned or power booster being bad. Any help with how to adjust the brake rod? Thanks
William

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Wednesday, June 8th, 2016 AT 12:25 PM

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Tiny
WRENCHTECH
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The rod has to be adjusted so there is a very tiny amount of play before it contacts the master cylinder. You just need to confirm that the master is returning fully to it stops and the rod is not preventing that.

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Wednesday, June 8th, 2016 AT 2:59 PM
Tiny
COBRAJET427
  • MEMBER

Does the master cylinder need to be off to adjust this? The dealership I went to said that they needed to pull master cylinder to adjust and it would be $190.00. They said that if it did not work that they would replace the power booster next. They would be questing as they did not know what the problem was. I told my niece that they would only be questing when I had the dealership on speaker phone. They called back an hour later and said that a new tech was walking by and said that it was out of adjustment by 10 mm, he fixed it and that is when they said if that did not work they would change the power booster. So if you could help me with the adjustment on the rod or what to try next I could use the help. Thank you.
William

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Thursday, June 9th, 2016 AT 3:21 AM
Tiny
WRENCHTECH
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Yes, the master has to be removed or at least pulled away from the booster some.

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Thursday, June 9th, 2016 AT 3:54 AM
Tiny
COBRAJET427
  • MEMBER

If the rod is out of adjustment would the brakes work at all? When I changed the master cylinder the brakes worked fine for a week and then started to act up and stick.

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Thursday, June 9th, 2016 AT 4:02 AM
Tiny
WRENCHTECH
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If the master is not able to completely return to its stop, it will not release pressure and it will build up a keep the brakes on.

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Thursday, June 9th, 2016 AT 4:41 AM
Tiny
COBRAJET427
  • MEMBER

Would the brakes work fine if the rod is out of adjustment and can you tell me how to check and see if the rod is out of adjustment and how to correct it?

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Thursday, June 9th, 2016 AT 5:05 AM
Tiny
COBRAJET427
  • MEMBER

Can you explain to me how to check to see if the master cylinder is returning completely and how to adjust the rod?

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Thursday, June 9th, 2016 AT 6:48 PM
Tiny
WRENCHTECH
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You need to have about 1/16" of free play before contacting it.

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Thursday, June 9th, 2016 AT 6:50 PM
Tiny
COBRAJET427
  • MEMBER

Is that between the power booster and the master cylinder. I can take it apart and put it back together with no problem, but I have never dealt with this before.

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Thursday, June 9th, 2016 AT 7:06 PM
Tiny
MHPAUTOS
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There is a special tool to check the push rod length is correct, but as wrenchtech says you need a small amount clearance so the brakes do not bind up with residual pressure.

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Saturday, June 11th, 2016 AT 3:28 AM
Tiny
COBRAJET427
  • MEMBER

If the rod is out of adjustment would the brakes work fine for a week and then lock up or would that be something else. This is what happen and that is why I am asking so many questions as I am trying to understand this.

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Saturday, June 11th, 2016 AT 6:14 AM
Tiny
2CARPROS KEN
  • ADMIN
  • 9,328 POSTS

When the brake are locked up, safely raise each wheel to see if all wheels are locked up, if so then its the adjustment at the master which can be checked simply be loosening the masters mounting bolts, if the wheel starts to roll then that is the problem, if you only have one wheel that is locked the problem is the rubber flex line need to be replaced, if one of the rear wheels are locked and it has drum brakes remove the rear wheel and look and the brake shoes they could be falling apart.

Please let me know what you find.

Best, Ken

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Saturday, June 11th, 2016 AT 1:49 PM
Tiny
COBRAJET427
  • MEMBER

After driving the car the left front and right rear are locking up. I have changed the left front brake caliper as it was sticking when I tried to push the piston in and rotor along with all four brake hoses. I have also changed the master cylinder, could you give me an ideal of what to do next. Thank you William

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Sunday, June 12th, 2016 AT 11:02 AM
Tiny
2CARPROS KEN
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This sounds like the ABS module and valve are bad and need to be replaced.

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Sunday, June 12th, 2016 AT 12:10 PM
Tiny
COBRAJET427
  • MEMBER

It appears that it was the ABS module thanks for your help

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Monday, June 20th, 2016 AT 5:36 AM
Tiny
2CARPROS KEN
  • ADMIN
  • 9,328 POSTS

Glad to hear we could help you fix the problem, please use 2Carpros anytime, we are here to help.

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Monday, June 20th, 2016 AT 7:46 AM
Tiny
COBRAJET427
  • MEMBER

Ken my niece drove the car for 2 weeks with no problem and then driving a short distance today the left front and right rear locked up again. Google said something about taking the vacuum line from the power booster loose to see if that would release the brakes. We took it loose and the brakes released but google did not tell us which way to go from there. Do you have any thoughts in the matter. We drove the car a short way after hooking up the vacuum line and they are working fine. By the way the car was off when we pulled the vacuum line off if that matters. Anything that you can think of will be helpful. Thanks
William

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Monday, July 4th, 2016 AT 3:36 PM
Tiny
KHLOW2008
  • EXPERT
  • 41,957 POSTS

The problem is due the master cylinder being partially activated. If you drive a longer distance, the brakes would lock up again.

I see you have been going through a lot of work and the problem is still not resolved. You mentioned the Toyota tech saying the adjustment was out by 10 mm. You must be kidding or the tech does not know what he is talking about. A 1 mm difference is possible but a 10 mm difference would not allow you to bleed the master cylinder or brake system after replacement of the master cylinder.

The master cylinder has dual chambers and each chamber supplies pressure to 2 wheels. This system is a diagonal system meaning, FR + RL for one chamber an FL + RR being supplied by the other chamber.

Did you check the pedal free play? If the brake switch is out of adjustment, it can result in the brake pedal being partially depressed causing the problem.

Booster rod adjustment is rather troublesome and if pedal adjustment is not the cause of the problem, you would still need to get this done. I have a suggestion which you could try.

When problem occurs, loosen the master cylinder holding nuts slightly and pull the master cylinder away from booster. If brakes releases, it means the adjustment is out. Remove the holding nuts. Make 2 washer with a thin card board and place one each between the master cylinder and booster stud. Reinstall the master cylinder and retest. You may need to repeat this again with addition of gasket to increase the clearance if necessary.

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Monday, July 4th, 2016 AT 4:19 PM
Tiny
COBRAJET427
  • MEMBER

Ken remember last time it locked up I raised the vehicle and only the left front and right rear were locked the left rear was loose and turning freely. Do you think that the new master cylinder could be bad. There is about an inch of free play.

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Monday, July 4th, 2016 AT 5:23 PM
Tiny
KHLOW2008
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If you mean the pedal stops after about an inch, that is not the free play I mentioned about. Free play is the amount of clearance the pedal has before the brake booster rod is pushed by the pedal. This free play is adjusted by turning the brake switch in or outwards.

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Tuesday, July 5th, 2016 AT 8:05 AM

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