When the pedal gives in to the floor the burps and bike pump noise stops as well

AKAI

MEMBER
2005 TOYOTA 4RUNNER
4.7L
V8
4WD
AUTOMATIC
92,000 MILES

Had master brake cylinder assembly replaced, brakes work better but not as good as before master cylinder failed. I noticed that when the car is parked and engine is off the brake pedal never gets firm after pumping it down a few times, no gradual pressure from each pump instead after about 4 or 5 pumps the pedal gives in to the floor. Here is a little video of the reservoir while pumping the brakes when the engine is off not sure if the burps/gurgles are normal or not. Also the first few presses sound like a bike pump but when the pedal gives in to the floor the burps and bike pump noise stops as well.

5 Replies

AKAI

MEMBER
4 POSTS

Sorry, here is the video:

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Saturday, July 27th, 2019 AT 1:16 AM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

This sounds like you have air in your vehicle's brake lines that needs to be bled out. Brakes systems are basically hydraulic systems that utilize brake fluid pressure to compress calipers with pads on them to squeeze a rotor that is attached to your vehicle's wheels, much like a 10 speed bikes brakes, but instead of your hand applying pressure, brake fluid is compressing the brakes hydraulically with much more force. The brake lines must be completely sealed and have no air in them, otherwise the brakes won't work properly. I have included a couple of links down below for you to go to:

I would suspect there is air in the lines. These guides can help you fix it.

https://youtu.be/w7gUsj2us0U

and

https://youtu.be/WDxvEQrMkBg

and

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Please run down these guides and report back.

Please go through these guides and get back to us with what you able to find out.

Thanks,
Alex
2CarPros

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Saturday, July 27th, 2019 AT 4:18 AM

AKAI

MEMBER
4 POSTS

Thank you for the response I appreciate it!
All the work has been done at the Toyota dealer under warranty, I went back after they replaced the master cylinder assembly for $3700 about 3100 for MC and 600 labor (under warranty) because it was still not right! I told the service adviser it fells like there is air in the line. They supposedly did another brake fluid exchange and bled the system again. Still they gave it back to me exactly the same as I brought it back, telling me that it is okay now and normal to not build pressure from pumping when the car is turned off. Not sure what to do now?

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Saturday, July 27th, 2019 AT 5:31 AM

AKAI

MEMBER
4 POSTS

They just never get tensed up or firmer when you press the break with the engine off a few times, and there is is still a lot of extra pedal movement when driving the brakes do seem to work just feels was too loose.

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Saturday, July 27th, 2019 AT 5:36 AM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello again,

This could be a problem with the height adjustment on your brake pedal. In the diagrams down below I have included the directions on how to test and adjust the brake pedal on your vehicle. Please go through the guides down below and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

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