2010 Vibe, Can't get air out of brakes!

Handling, suspension, and brake tuning discussions
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kgw51gmc
Posts: 9
Joined: Mon May 23, 2022 6:12 am

2010 Vibe, Can't get air out of brakes!

Post by kgw51gmc »

2010, 2.4 L, 5 speed "Base wagon 4 door) Vibe. 140,000 miles. Perfect car except........have to replace rear calipers once ever 18 months or so. They stick..... Literally every 18 months give or take you have to replace a rear caliper.



I installed caliper number 7 last week. We've had car 9 years. It shouldn't be related to a master cylinder, unless you can program a master cylinder to drag a rear caliper every 1.5 years...



Anyway---the car was up on ramps on the front end doing an oil change etc, so the front was elevated significantly. I went ahead and did the rear drivers caliper replacement while it was elevated like that. Bled the brakes like that too. It never got any pedal back. It's soft and spongy all the way to the floor. So I re-bled on level ground, didn't help.



I suspected that miraculousy the booster or master may have failed for no reason while replacintg the caliper (looking for anything). All the "test your brake booster" tests come out great. Booster works great. The turn the car off and push the pedal a few times to release all the booster pressure and get that HARD pedal works fine. Start it up and feel the pedal fall. Then to test the system for leaks, with car off, stand on that pedal for 30 seconds..............no leaks, it holds fine. But start the car and use the brakes.... the pedal is soft and will eventually go 99% to the floor.



So I BLED THE WHOLE SYSTEM with no result. SO then I went ahead and replaced the master cylinder (throw money at it) 2009-2010 says in the book, can't bench bleed master cylinder, have to do it on the car. So mounted to booster and then put the bleeder hoses on, routed up into the resevoir, assitant pushed the pedal while I watched until no more air bubbles. Hooked up the lines quickly, then cracked the lines open while assitant pushed pedal to get air out and then bled the whole system as follows:



Put the car up on blocks wood, all 4 wheels removed. I had an assistant help and pressure bled all 4 wheels in the correct order. Helped the problem zero. I then, in the correct order, opened the bleeders and let them gravity bleed through clear hose into a 5 oz baby food jar. Filled up the jar full each time on all 4 wheels. Helped zero.



2010 vibe master cylinders are mounted at an angle, my next move is to remove it from booster while hooked up and try to get any air out of the high side of the bore that might be trapped in there. I may have trapped air in the original master while it was up on ramps....then removed a good master and put a new one in but since it's mounted at an angle anyway I may have to raise rear of car and dismount it from booster to tilt it and rebleed somehow.



HAS ANYONE ON HERE EVER REPLACED A MASTER CYLINDER ON A 09/10 VIBE? IF SO, DID YOU HAVE THIS PROBLEM?
2010 Vibe, base, 4 door, 5 speed, 2.4, 140K miles.
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