More brake help needed!
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 7,928
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From: More cowbell...
St. Jude Donor '04
More brake help needed!
So here were the symptoms- most of the pedal movement, would do very little to stop the car (sloppy brake pedal), then the pedal would get hard as a rock, and seemed to have very little stopping power.
I did the test where I turned off the car, with my foot on the brake- no pedal movement. I also tried pumping the brake after the car was off, and could get one pump before it was solid.
So, everyone said it was a power booster. Replaced the power booster, to no avail. Still the same symptoms (the pedal feels like it might actually be sloppier now). Any ideas?
Also, the brakes seem to be more effective at speed, than when I am moving slowly.
I did the test where I turned off the car, with my foot on the brake- no pedal movement. I also tried pumping the brake after the car was off, and could get one pump before it was solid.
So, everyone said it was a power booster. Replaced the power booster, to no avail. Still the same symptoms (the pedal feels like it might actually be sloppier now). Any ideas?
Also, the brakes seem to be more effective at speed, than when I am moving slowly.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
The part about the brakes being more effective at speed is a little weird. Other than that, it just sounds like air in the system. Do a thorough flush and bleed. Fully evaluate the hydraulics and everything else while doing so and go from there. What's the history? Has the system been regularly flushed every year or two? How many miles, is the car regularly driven? Are the calipers moving freely? Pads in decent shape?
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
Thanks for chiming in 
The current state of the brakes is this-
Pads are relatively new (5000 miles, light use), so they should be fine. The system has not been regularly flushed, so I will give that a try next (I tried bleeding the brakes, but that did no good.. I guess a full drain and refill is the way to go). The car has not been regularly driven lately.. Its been down because of some other mechanical issues over the past year or so (driven very sporatically). The calipers seem to be moving freely.
The current state of the brakes is this-
Pads are relatively new (5000 miles, light use), so they should be fine. The system has not been regularly flushed, so I will give that a try next (I tried bleeding the brakes, but that did no good.. I guess a full drain and refill is the way to go). The car has not been regularly driven lately.. Its been down because of some other mechanical issues over the past year or so (driven very sporatically). The calipers seem to be moving freely.
Team Owner
Joined: May 2002
Posts: 24,337
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Sounds like a hydraulic problem. Possibly one of the brake circuits isn't holding pressure, either because the line is broken somewhere, or because it has a bunch of air in it. The master cylinder has seperate pistons for front and rear. If either side doesn't hold pressure, that piston bottoms out quickly at half pedal, and only then does it begin putting pressure on the other circuit.
Also a broken combination valve can do it, but I've never heard of one failing.
That extra looseness you feel in the pedal is from improper booster pushrod adjustment. You need to back the tip out a turn or so, it's pretty tough, but can be unscrewed with channellocks and a small box end wrench. The tip of the pushrod should almost touch the master cyl piston when the pedal is all the way up.
Also a broken combination valve can do it, but I've never heard of one failing.
That extra looseness you feel in the pedal is from improper booster pushrod adjustment. You need to back the tip out a turn or so, it's pretty tough, but can be unscrewed with channellocks and a small box end wrench. The tip of the pushrod should almost touch the master cyl piston when the pedal is all the way up.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by MarkLT1
Thanks for chiming in
The current state of the brakes is this-
Pads are relatively new (5000 miles, light use), so they should be fine. The system has not been regularly flushed, so I will give that a try next (I tried bleeding the brakes, but that did no good.. I guess a full drain and refill is the way to go). The car has not been regularly driven lately.. Its been down because of some other mechanical issues over the past year or so (driven very sporatically). The calipers seem to be moving freely.
The current state of the brakes is this-
Pads are relatively new (5000 miles, light use), so they should be fine. The system has not been regularly flushed, so I will give that a try next (I tried bleeding the brakes, but that did no good.. I guess a full drain and refill is the way to go). The car has not been regularly driven lately.. Its been down because of some other mechanical issues over the past year or so (driven very sporatically). The calipers seem to be moving freely.
