2006 sr5 weird brake pressure loss at a light.

[rpete]

Hey all I️ have a question that has baffled my local Toyota dealership and what seems like a major issue to me. For about the past year when applying the brakes for a prolonged period of time I️ consistently loose pressure until the pedal bottoms out, usually takes about 2-3 minutes, however if I️ ever release the brakes and reapply it always has full pressure again. They said they are at the point of needing to just start replacing things trial and error style. I’m mainly worried it will get worse or just go poof someday. No visual leaks, is always consistent and always happening, and there is always more pressure if I️ release and reapply. Any suggestions or anyone had this issue before?


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[TechWrench]

Hey all I️ have a question that has baffled my local Toyota dealership and what seems like a major issue to me. For about the past year when applying the brakes for a prolonged period of time I️ consistently loose pressure until the pedal bottoms out, usually takes about 2-3 minutes, however if I️ ever release the brakes and reapply it always has full pressure again. They said they are at the point of needing to just start replacing things trial and error style. I’m mainly worried it will get worse or just go poof someday. No visual leaks, is always consistent and always happening, and there is always more pressure if I️ release and reapply. Any suggestions or anyone had this issue before?


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You need to find another dealership.

What you are describing is typical of leaking internal seals in the master cylinder. Because the seals are leaking internally, you will not see any external fluid leaks. Unlike years ago, where one could rebuild a master cylinder, I believe the only fix for this now is to replace the master cylinder. I haven't had to do this on either of my '03's, so far, so I can't give you any specific cost information, but as I understand it from other threads I have read, the replacement costs are quite expensive.

Do a search on this site for master cylinder replacement, and you should find more information.

 

[rpete]

You need to find another dealership.



What you are describing is typical of leaking internal seals in the master cylinder. Because the seals are leaking internally, you will not see any external fluid leaks. Unlike years ago, where one could rebuild a master cylinder, I believe the only fix for this now is to replace the master cylinder. I haven't had to do this on either of my '03's, so far, so I can't give you any specific cost information, but as I understand it from other threads I have read, the replacement costs are quite expensive.



Do a search on this site for master cylinder replacement, and you should find more information.

That’s what the consensus seems to be. I️ live in Utah and have yet to find a mechanics shop let alone a dealership that I️ have not even been satisfied with but not even tolerant with. They say bleeding the brakes might help but I’m not sure how that wood do anything


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[TechWrench]

That’s what the consensus seems to be. I️ live in Utah and have yet to find a mechanics shop let alone a dealership that I️ have not even been satisfied with but not even tolerant with. They say bleeding the brakes might help but I’m not sure how that wood do anything


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As I understand the symptoms you describe, bleeding the system will have little or no effect on your problem. Bleeding is usually done to eliminate air in the system/lines. The symptom of air in the system is usually a 'spongy' feeling in the pedal, which does not go away when you pump the pedal. If you have an initial 'hard' pedal feel, and the pedal stays firm, but drops with constant pressure. This is a classic indication of fluid slipping by the seals in the master cylinder.

 

[rpete]

Update to my story.
So my dealer said they wanted to bleed the brakes and start guessing and checking as i stated. So i told them I️ would like to pick it up as is. After that and after i just showed up to pick it up because i got tired of waiting to here back, the service writer says his master tech is the one who has been working on it and that the master tech has has the same year runner and if he plays with the brake at a stop he can get his peddle to bottom out as well so he wouldn’t worry about putting any more money into it. i wish i could just find a shop around here that new what they were doing and could communicate.


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