Brake Pedal sometimes mushy??
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 5,404
Likes: 45
From: Arlington Tx
St. Jude Donor '08
Brake Pedal sometimes mushy??
My '92's brakes work well enough, but the brake pedal is mushy/soft for the first half of the travel down sometimes. After that, they work fine. Sometimes they're normal and it has a firm pedal.
What might be wrong??
Bleed the brakes? New master cylinder? booster?
What might be wrong??
Bleed the brakes? New master cylinder? booster?
Burning Brakes
Joined: May 2006
Posts: 857
Likes: 1
From: Morrisonville Illinios
Sounds like master cyclinder is shooting craps not a bad fix. Are you lossing any fluid you might want to check below the power brake booster to see if they are any leaks and have seen the MC leak into the booster so the fluid would be sucked into the intake and not have any visible leak. When replacing the fluid use the Valvoline synthec brake fluid it will last the rest of the system life.
Good Luck wro87
Good Luck wro87
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
*Edit*
Oh....on your 92.....There is an ABS module that needs resetting from time to time. Do a search and reset that module before you do anything listed below......no.....I don't know how to do it so I cannot tell you....but someone will.
*Edit off*
Next time it happens, note the engine temps.....
You'll find that as the MC ages, and when the temps are hot...you'll get a little blow by on on old MC.
Speed up or get clean air and the engine temps come down, the MC starts working again.
coefficient of thermo expansion is playing a part with Aluminum and aged o-rings.
that is why you the "Sometimes"
As the months go by, it'll get worse and you'll find yourself having to pump it while in stop and go traffic while it works fine driving down the road on a cool evening.
swapping it is a 2 on the difficulty scale of 1-10. the only reason it is not a 1 is due to those darn plastic cups and how hard they are to get off the old MC and replaced onto your new MC.....they are a bear....Some replacement MCs come with new cups....you may compare prices and pop for one of those if the price is acceptable.
And if you don't know how to bleed brakes, this may be a challenge. (amazing how many people have issues with that 10 minute task)
Oh....on your 92.....There is an ABS module that needs resetting from time to time. Do a search and reset that module before you do anything listed below......no.....I don't know how to do it so I cannot tell you....but someone will.
*Edit off*
Next time it happens, note the engine temps.....
You'll find that as the MC ages, and when the temps are hot...you'll get a little blow by on on old MC.
Speed up or get clean air and the engine temps come down, the MC starts working again.
coefficient of thermo expansion is playing a part with Aluminum and aged o-rings.
that is why you the "Sometimes"
As the months go by, it'll get worse and you'll find yourself having to pump it while in stop and go traffic while it works fine driving down the road on a cool evening.
swapping it is a 2 on the difficulty scale of 1-10. the only reason it is not a 1 is due to those darn plastic cups and how hard they are to get off the old MC and replaced onto your new MC.....they are a bear....Some replacement MCs come with new cups....you may compare prices and pop for one of those if the price is acceptable.
And if you don't know how to bleed brakes, this may be a challenge. (amazing how many people have issues with that 10 minute task)
Last edited by jhammons01; Aug 11, 2010 at 01:08 PM.
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
Cruise-In IV Veteran
St. Jude Donor '12
Have you COMPLETELY flushed the fluid and bleed the brakes?
I learned to live with it last year cause one weekend I'd get a great bleed and the pedal would be solid till after the next track event. I'd beel again and get it "close" and would have a longer pedal. Got tired of bleeding after every event and flushing every other event. Replaced booster (just for drill), master and all 4 calipers. Now I have a good pedal and just have to bleed after each event.
I learned to live with it last year cause one weekend I'd get a great bleed and the pedal would be solid till after the next track event. I'd beel again and get it "close" and would have a longer pedal. Got tired of bleeding after every event and flushing every other event. Replaced booster (just for drill), master and all 4 calipers. Now I have a good pedal and just have to bleed after each event.
