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2004 grand prix gt brake problm

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peter

New member
REPLACED MASTER BRAKE CYL . WHEN APPLED FEEL LIKE ON ICE AND KEEP GOING .DID POWER BOOSTER TEST BY FOOT FEEL LIKE OK .WAS DOING THE SAME THING BEFORE. CHECK ALL VACUUM LINES TOO.THE ONE I TOOK OFF LOOKED LIKE SAND IN SIDE AND BLACK AND THICK.WIFE CAR NOT TO HAPPY:th_angry-teeth: HELP:th_shakinghead1:
 


Still same problem bleed the brakes twice.Still feel like i am on ice.I got a better pedal but not stoping like it should.Would speed sensor mess it up too my brother said he read on line maybe it part of it.helppppp pulling my hair out
 
next to the master is the abs pump, on that you should find 2 bleeder valves, bleed those 2 first, it may take a while to get all the air out. (just like a caliper) then re bleed the calipers, starting with the pass rear, then the drivers side rear, then the pass front, then the driver side front last.

i like to use a piece of vac tubing or wiper fluid tube, put the box wrench on the bleeder, then push the tube over the bleeders nipple, and then put the tube in a bottle to let the fluid dump into. nice and clean that way. i do that on the calipers too.
 
Bleeding procedure is

Right rear
Left rear
right front
left front

You should use about a big bottle of fluid when swapping a master cylinder.
 


Ibleed the brakes in that order. Ichecked my abs pump it has no bleeders on it .I have a firm pedal and I did the booster test pump pedal 5 times hold pedal down and start car pedal should go down a little meaning that it is working .Let car run 5 min then turn car off and pump pedal 5 times and pedal should rise with pump of pedal and Iget firm pedal
 
Ok..so if you have a firm pedal and aren't stopping. Let's ask the next question.

Did you soak your brake rotor and or pads with brake fluid aka oil?
 
i just did some looking around. did you bench bleed the new master? if not thats your problem.

you new pump should have come with a bleeder kit, 2 hoses tha screw into the exit holes, you loop them into the top and under the fluid line, then with a screw driver, Philips is proffered, you push the piston in and out on the back side of the new master till no bubbles come out of the tubes.

then install the master.
 


you lost me now, is your pedal soft? or hard as a rock and dont move down with out a lot of hard pushing?

if its soft, you still have air in the system,

if its hard you have no vacuum to the booster most likely. there is a fat hose from the engine to the round booster behind the master cylinder, check that in place also.
 
Hard a lot of pushing.HAVE TO PUMP THEM TO STOP . I did the foot test for power booster pump pedal 5 times start car pedal should go down a little it did that turn car off and pump pedal 5 times pedal should come up It did that.Also did test with carb cleaner to test for vacuum leaks spray around engine and down the lines to gas tank avap line engine should change sound if leak.:th_scratchhead: On the internet and auto zone advance auto looked. AND THE GREAT HELP YOU AND EVERYBODY ON THIS FORUM
 


ok please just answer this question.

when the cars running and your coming to a stop, is the pedal hard as a rock? or going to the floor?
 
Hard as rock. Maybe have to start over again that I did not get all the air out of master.Maybe have to bench bleed over:th_scratchhead:
 
hard as a rock is a vac problem. like hitman said, make sure the vac hose is hooked up and not leaking. the booster is probably dead.


next question.....why did you change the master cylinder? because of the hard pedal? or now you have a hard pedal.

all the small details from the start will help us up to help you, its hard to fix something with 1/2 a story.
 
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