Low brake pedal

Tiny
CARPETMAN1759
  • MEMBER
  • 1990 GEO PRIZM
  • 1.6L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 135,000 MILES
Installed new brakes [hoses, calipers, proportion valve, master cylinder]. Bled brakes four times and no air in the system. The problem is peddle travel. You have to push the peddle down three inches before you feel the brakes grabbing. The brakes do work but the peddle is almost on the floor. I have four wheel disc on this car. Is there an adjustment for this? Everything is new but the metal lines [which checked out okay] and the power booster.
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Sunday, April 30th, 2017 AT 2:27 PM

11 Replies

Tiny
KEN
  • ADMIN
Hello, '

It sounds like you may have a caliper slide that is stuck not allowing the caliper to "float" which causes a low brake pedal.

Here is a guide to help you fix the problem.

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

Please let us know what happens.

Cheers, Ken
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Wednesday, May 3rd, 2017 AT 10:09 AM
Tiny
CARPETMAN1759
  • MEMBER
All calipers were greased. Took them all off and checked there travel and they seem to slide perfectly. All slide pins are new so no burs on them. I don't know where to go next?
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Thursday, May 4th, 2017 AT 5:36 AM
Tiny
KEN
  • ADMIN
Take 3 pairs of vise grips and gently close them over the brake flex hoses to stop the fluid flow. Then push the brake pedal. This should tell you if the problem is at the master or the wheels. It could be the push rod going into the master is not adjusted right or you got the wrong master cylinder on there.

Lets find out! Please get back to me.

Best, Ken
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Thursday, May 4th, 2017 AT 9:38 AM
Tiny
CARPETMAN1759
  • MEMBER
Okay, it took me a few days to get back to it. Installed vise grips on both back hoses and the right front. Peddle travel is one inch before getting hard. Now this is with the car not running. Did not try to start car and test. What is my next step?
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Saturday, May 13th, 2017 AT 11:45 AM
Tiny
KEN
  • ADMIN
Yes start the car and see where the pedal is. If the same the problem is at one of the wheels, Remove the vise grips one at the time while repeating the test until the pedal drops, this will be the wheel the problem is at.
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Tuesday, May 16th, 2017 AT 11:15 AM
Tiny
CARPETMAN1759
  • MEMBER
Also would you think I have the wrong master cylinder? The car with rear drum brakes takes a different master cylinder then the 4 wheel brake car. The difference is the bore size. I will test the brakes as soon as possible and get back to you. Thanks for your info!
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Tuesday, May 16th, 2017 AT 3:49 PM
Tiny
KEN
  • ADMIN
Please let us know what happens.

Cheers, Ken
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Wednesday, May 17th, 2017 AT 11:30 AM
Tiny
CARPETMAN1759
  • MEMBER
I clamped the three wheel hoses and got a good peddle[one inch travel] but once I started the car it went to the floor again. Peddle travel is the same while the car is running as it was without the hoses clamped and running. I guess it must be the master? I have not touched the rod adjuster. The old master had a one inch travel until a seal blew out. That rod adjustment is done with a gauge type of tool, which I don't have. I don't have any type of measurement on it to check it. What do you thick I need to do next Ken?
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Friday, May 19th, 2017 AT 1:53 PM
Tiny
KEN
  • ADMIN
Yes it does sound like the master is bad. When you have it off check the push rod from the booster.

Here is a guide to help you get the problem fixed.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

Please let us know what happens.

Cheers, Ken
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Monday, May 22nd, 2017 AT 9:35 AM
Tiny
CARPETMAN1759
  • MEMBER
Okay, seeing this is an odd master cylinder I can't get it until Friday. My main concern is the rod adjustment coming out of the power booster. My manuals show a measurement tool gauge for this but no measurement what so ever. When I take this master off I want to make sure that everything is correct. It is a real pain to get to this master cylinder due to the factory strut brace and the way the lines run on top of it.
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Monday, May 22nd, 2017 AT 10:38 AM
Tiny
KEN
  • ADMIN
Yep, check for the travel to the master which is easier if you just remove the mounting bolts and then lightly push the pedal until the master moves. If you have to push it more than 1/4 in then adjust the rod outward.
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Monday, May 22nd, 2017 AT 4:03 PM

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