Arghhh! Spongy Breaks.
05-31-2012, 01:00 PM
#1
Drifting
Thread Starter
Arghhh! Spongy Brakes.
The last two trips have included a brief slip when I applied the brake, then a spongy -- gotta stand on it to keep it stopped-- feel. Needless to say I haven't driven it since and look to address the brake issue this weekend, but I'm fishing here for some "could be's."
My bet is the master cylinder is shot, but that is purely speculative.
I notice no leaking fluids.
Other possible causes of these symptoms? Air in break line seems unlikely. Need of fluid change / line bleed, a maybe. Any other possibilities, gents?
My bet is the master cylinder is shot, but that is purely speculative.
I notice no leaking fluids.
Other possible causes of these symptoms? Air in break line seems unlikely. Need of fluid change / line bleed, a maybe. Any other possibilities, gents?
Last edited by Stroh; 05-31-2012 at 01:34 PM.
05-31-2012, 01:13 PM
#2
Team Owner
Member Since: Jun 2000
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Run out. If the rotors have been off the car in the past, check the run out at all four corners.
05-31-2012, 02:42 PM
#4
Burning Brakes
There could be a leak.
They don't necessarily end up on the garage floor.
Is the level in the master cylinder low?
Look under the carpet at the drivers feet.
Power brakes? Look inside the booster.
They don't necessarily end up on the garage floor.
Is the level in the master cylinder low?
Look under the carpet at the drivers feet.
Power brakes? Look inside the booster.
05-31-2012, 03:33 PM
#5
Race Director
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Spongy is usually air in the system (from somewhere)
If the rotors are running out like Mike says, the old "lip" style seals would (could) actually pump air into the system.
The "o-ring" update seems to have fixed that but just hides the fact that the rotors are running out.
When checking the runout, it's best to put all 5 nuts on and torque/tighten them to simulate the way the rotor will be with the wheel on. I use a air-ratchet (not an impact) and make sure it stalls on each nut (only about 40 ft-lbs of torque really) to speed things up
If you do need to shim, and it's a fair amount (say .006+) put some thinner shims on the middle studs.
Also, if your bearings are loose, your reading will be all over the place
I had a small leak into the master/booster joint and then down the firewall and blown along the bottom of the car, never hit the ground.
Mooser
If the rotors are running out like Mike says, the old "lip" style seals would (could) actually pump air into the system.
The "o-ring" update seems to have fixed that but just hides the fact that the rotors are running out.
When checking the runout, it's best to put all 5 nuts on and torque/tighten them to simulate the way the rotor will be with the wheel on. I use a air-ratchet (not an impact) and make sure it stalls on each nut (only about 40 ft-lbs of torque really) to speed things up
If you do need to shim, and it's a fair amount (say .006+) put some thinner shims on the middle studs.
Also, if your bearings are loose, your reading will be all over the place
I had a small leak into the master/booster joint and then down the firewall and blown along the bottom of the car, never hit the ground.
Mooser
06-01-2012, 01:31 PM
#6
Drifting
Thread Starter
Thanks Jet & Mooser,
Can't wait to get cranking on that old shark this weekend. I've been chomping at the bit all week.
It's time for an exam... and maybe a beverage along the way. Man, it's been a long week, despite the Holiday start. Thanks again all, I appreciate the direction.
Can't wait to get cranking on that old shark this weekend. I've been chomping at the bit all week.
It's time for an exam... and maybe a beverage along the way. Man, it's been a long week, despite the Holiday start. Thanks again all, I appreciate the direction.