• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Brake pedal return issue... unsure if booster or something else

U

UmmScott

New member
Hey guys. Proud new owner of an 04 grand prix. Always been a GM guy and this car compliments my 00 yukon pretty well.

Anyhow.. my brake lights stay on and the trans converter clutch wont lockup due to the brake pedal switch not making.
It doesnt make because the pedal doesn't come all the way back.
I can lift if back with my foot about another inch i would say. When i do this the switch works.

What is supposed to bring the brake pedal all the way back? I dont see any sort of adjustment on the brake pedal. I dont think the brake pedal switch is supposed to do that.
I think the booster is damaged somehow. The brake system itself works fine with no issues.

What do you guys think?

Sent from my SM-G975U using Tapatalk
 


Heres a pic of it [emoji106][emoji106]
4fc47cb76dfd95b91cc1c97057b6658a.jpg


Sent from my SM-G975U using Tapatalk
 
Scottydoggs said:
try filling the master and bleeding the master then the lines. might have air trapped in the system causing it.
Click to expand...
Ok. Ill double check that. There is this weird mechanical feeling when i lift the pedal up and push back down with my foot.
Hard to describe without seeing it in person.

Pretty sure the master cylinder is full.

Its got 189k miles on it

Sent from my SM-G975U using Tapatalk
 
how do the brakes feel over all? the pedal mushy and push to the floor or normal firm feeling? or maybe hard as a rock?

if its mush the master is going bad, or it needs to be bleed. rock hard means the boosters not working right. engine off if you pump the brakes the pedal should get harder and harder with each push as it uses up the vacuum in the booster. they can rust and leak out the vacuum on ya running and cause a hard pedal.
 
Scottydoggs said:
how do the brakes feel over all? the pedal mushy and push to the floor or normal firm feeling? or maybe hard as a rock?

if its mush the master is going bad, or it needs to be bleed. rock hard means the boosters not working right. engine off if you pump the brakes the pedal should get harder and harder with each push as it uses up the vacuum in the booster. they can rust and leak out the vacuum on ya running and cause a hard pedal.
Click to expand...
They feel fine overall.
No binding, no spongyness, firm normal GM brake pedal except for not coming back all the way.

Not feeling any drag from them either

Sent from my SM-G975U using Tapatalk
 


odd, has to be the booster or master. that rod off the brake pedal pushes through the booster then into the master, so something is not working right. likely booster is messed up. not sure if you can lube it any. if you took the master off maybe you could work the pedal and spray the shaft down.
 
Ok guess what... you guys wont believe this, ill have to take pics tomorrow when its brighter.

Was looking into this and...when i pushed on the brake pedal with normal effort, something popped.
I opened the hood...
The entire booster had broken off of its mounting flanges.
You can literally wiggle the entire master cylinder/booster assembly all over the place.

Well i think i found the Problem!! LOL

also... i am so incredibly thankful that i found this out while i was parked safely in my driveway.
This could have been VERY BAD if it happened while driving

Sent from my SM-G975U using Tapatalk
 
now thats a new one. the booster gets pushed in place and twists to lock in place.

heres a vid, the bracket on the fire wall may have rotted on you for this to just come free for no reason.

YouTube
 
You must log in or register to reply here.
Back
Top