Brake problem
Thread Starter
Racer
Joined: Jan 2006
Posts: 393
Likes: 0
From: Palm Springs CA
Brake problem
The pedal on my 1995 A4 coupe became very hard to push and had very little stopping power. This happened out of no where I drove the car to store parked all normal and had driven it a couple hours previous with no trouble ( ever ). When I cam out of the store and started the car when backing up I noticed hard to push pedal with little stopping power, I drove home about 5 minutes very carefully, but no light came on. No leaks to notice, according to my Haynes the booster can stick, any other ideas, I have yet check it, but will shortly, brakes have made no noise and have been normal since purchase in 09/2004.
N7
N7
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
This is classic brake booster symptom. Normally when you shut off engine you should be able to press brake pedal about three times each time it should get harder as vacuum in booster dissipates. If no vacuum due to hole in blatter you will always have hard pedal. Also check the vacuum line to booster, make sure it is not broken, pull off while engine running and put your thumb over hole in hose to check for vacuum. 
And… check idle speed at this time, put line back in booster, idle should be the same, if not and is higher, booster is definitely bad…and you have found your problem. 
Thread Starter
Racer
Joined: Jan 2006
Posts: 393
Likes: 0
From: Palm Springs CA
Thanks, I had ran a search on brakes. I think it is the booster also, I will check the line as you indicated. Yesterday while stopped, as the car was hard to hold I put in nuetral and noticed the idle was slightly higher than normal around 850/900 compared to around 7.
N7
N7
Thread Starter
Racer
Joined: Jan 2006
Posts: 393
Likes: 0
From: Palm Springs CA
I ran the as mentioned above and it is the power booster, I can get the part for about 150usd. I have read the haynes and the procedure on the tech/perf. I called a shop I have done business with and they want 315usd for the part, and say the system needs to be bleed, neither of the procedures I read mention this. Is that needed?
Thanks,
N7
Thanks,
N7
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
If you got air in the system your brakes need to be bled. There is an adjustment rod for the brake booster-but I hesitate to suggest it, it's very touchy and over adjusting it can cause the brakes to drag. Try the bleeding first.
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Thread Starter
Racer
Joined: Jan 2006
Posts: 393
Likes: 0
From: Palm Springs CA
Thanks. I also read in chiltons that the pedal can be adjusted by going forward and backwards and braking. I do not have any leaks, and fluid level is good just slightly under the MAX setting.
N7
N7
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Chilton's is full of **it. That technique was used for cable actuated drum brakes.
You need to unscrew the bolt on the end of the booster pushrod to take up the slack. Every manual I've read says not to mess with them, that they're "factory calibrated", but every single one I've put in needed adjustment.
Try measuring the m/c piston depth and then unscrewing the booster pushrod to match it. You should feel a small amount of play when pushing the pedal down. If you adjust it too far and there's no play some very bad things can happen.
You need to unscrew the bolt on the end of the booster pushrod to take up the slack. Every manual I've read says not to mess with them, that they're "factory calibrated", but every single one I've put in needed adjustment.
Try measuring the m/c piston depth and then unscrewing the booster pushrod to match it. You should feel a small amount of play when pushing the pedal down. If you adjust it too far and there's no play some very bad things can happen.