leaky power booster?
Thread Starter
Racer
Joined: May 2008
Posts: 327
Likes: 2
From: Livermore California
leaky power booster?
my 1980 has developed a leak(?) in the power brake booster. i get soft pedal when i first start up but firms up once i get going and doesn't happen again, until the next time i start it up. anybody ever experience this? any ideas ... what hose to check, filters to replace? thanks.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
That sounds more like a bad master cylinder than a bad booster.
Before you start the car, does the pedal get hard when you press it in a few times? Then it gets soft when you start the car?
Before you start the car, does the pedal get hard when you press it in a few times? Then it gets soft when you start the car?
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Are you saying that the pedal is OK after JUST starting the engine or do you have to then pump the pedal? If it is OK after just starting the engine, it may be a leaking check valve on the booster.
Thread Starter
Racer
Joined: May 2008
Posts: 327
Likes: 2
From: Livermore California
i the pedal is good on start up whether i pump or don't pump. as i start to move (at idle) is when it feeld good then drops as i'm pressing down. when i let up and pump once it gets hard and pretty much dtays that way unitl next time. thanks for the suggestions Duke and DB.
Burning Brakes
Joined: May 2006
Posts: 857
Likes: 1
From: Morrisonville Illinios
IF your car is idling a little rough take the vacuum line loose and plug it. If the idle smooths out it is the booster also try to have a freind push the pedal when you have it disconnected to see if it is still soft. The master cylinder is an easy job to rebuild to keep the original or you can pick one up ready to go but you will need to bench bled the MC then all the calipers. If they are as old as the car and not been touch you might want to look at their replacement before the seals blow out and you do them next. There are alot of dealers out there that will sell you the whole system and in the past and on the c3 we just got I have used Muskegon Brake.
Good Luck wro87
Good Luck wro87
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
If the pedal slowly goes to the floor as you are pushing, your master cylinder is kaput and in need of a rebuild. You can rebuild it yourself of buy a rebuilt one from a autoparts store. Make sure you bench bleed the MC before install and you will not have any issues with air in the system.
