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2004 grand prix gt brake problm



ive only had one rust out on me, ( from the 80's) and i lost a hydro booster too in one of my trucks.

we did have another guy who had a hard pedal after a shop did his master tho, they did take the booster off iirc. he had to get another booster.
 
Wife came home said have no brake took out for a ride still have some brakes had to stand on them that how she got home with car .I take off down road do 30-40 miles a hour step on brake stop a little but keep going like rideing on ice you keep going .Was not leaking did what they call the spray test get carb cleaner with car runing spray around engine and down vac lines to rear of car if leak engie will change sound i sprayed big vac line from back of engine to booster also took off line and blew air in by mouth and plug other end almost blew my ear drums out. Could not find leak in line maybe bad master something bad inside flud was black inside maybe jam it up try to find kit to rebuild they dont sell it .There was alot of junk inside the old one .New one bench bleed put in car did not think i had to bleed whole thing because master bleed has abs system flud still in system lines should still be full. Checked my computer in forum did what was said to bleed lines got hard pedal did samething as before :mad: then did rebleed maybe junk still in line samething.
 
so your saying the pedal got hard to push, and this prompted you to do the master.

im thinking you have a bad booster. with the engine running pull off the vac hose from the booster, make sure its sucking lots of air, the engine should drop rpm's and almost stall when you do this. if you put your thumb over the end of the hose the car should run better. if this hose has suction, you booster is bad for sure.

when a master goes bad your brake pedal will hit the floor and have a holy sh1t i have no brakes at all feel. (soft mushy pedal)

bad booster or no vac to the booster makes the pedal hard, ( like when the cars off) and stopping is hard to get done but the car will stop.
 
I once had a bad mc in my dads 78 4x4 chevy and that was a hell of an of **** moment. I downshifted to 2nd and was coming up on a t road and just cranked it off. Missed hitting my buddies truck by about a foot. Took it home really slow in 1st gear and never lost brakes again after that one time but i changed it out anyway to be safe.
 
I did everthing I can thing of be fore I did master. Ipull the hose off engine and It stall out restart plug hose ran ok.I HAD A HOLY **** MYSELF ON HIGHWAY IN RHODE ISLAND BEFORE I MOVE TO FLORIDA . I was hopeing that was not the problem never had a bad booster before.THANK YOU :th_thumb-up:
 


I know the masters good. all the junk from the old one may have messed it up down line with the car it's the wife good thing having 2 cars
 
the booster is only bolted to the master, theres a rod from the brake pedal that pushes the piston inside the master, no brake fluid is involved.

looks like it just timed out on you.
 
I pulled the master cly off to recheck it .but i left the lines on to see if i can look inside the booster and check rod there is a black seal or groment behind master it has a hole for the rod. Part of it is torn would that mess up booster when you put on brake would the air lose power
 
its nothing you can see, except for the rod that will come out when you push the brake pedal.

its failed internally, and unsearchable. at least ive never heard of rebuilding one.
 
In the back of the master cly there is a brake booster front main seal that was bad made it lose vacuum air replaced it and booster worked better.Did not have to replace booster .Got seal from junk yard like brand new thank god for junk yards .Auto parts store has no listing of it or dealers .:th_peaceout: I save arm and leg for new one
 


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