Mighty Shilling

Ok, Just got off the track and had to go to work. I figure I either:
1) Boiled my brake fluid, thus adding air to the lines
or
2) Blew one of the seals in my brake caliper


Here is what I've noticed, and the back-history of my brake system:
Brakes were bled a month ago when my clutch slave cylinder went. When it went, I got to know the smell of burning brake fluid, as the leaking cylinder somehow got to the exhaust.

WELL anyway, on the track today I had a little of that smell, but not for long. happened once. So, on the track, I locked up the brakes a couple of times, so I know they're working well... As the brakes got hotter and hotter, I was still able to stop perfectly well. Got off the track, took out the good ole infra-red thermometer, and my rotors were around 402 degrees fahrenheit. (my dad's Turbocharger, hot side topped out at 804 degrees fahrenheit )

Anyway, after I loaded up the car, I got in and started the drive home. Brake pedal seemed a little spongy, so I'm not sure. Also, I had brake fluid coming out of the cap of my resevoir, which is on VERY tightly... I think I need a new seal for that.

Mighty Shilling

sorry...need to finish my thought...

Anyway, I was thinking, a while back when I was painting my calipers and installing SS brake lines, I noticed the seals for the pistons on some of the rear calipers were kinda ugly, and figured a rebuild will be coming soon. 2 years later, I am now suspecting a rebuild.

The reason I think I need to rebuild my calipers is because of the slight brake fluid smell, the sponginess of the pedal, and the torn dust seal on the rear caliper....

What do you think? I'm gonna bleed the brakes when I get home so that way I'm able to check out the system....

but if brake fluid is boiled, does it result in a spongy pedal?

Sam Lin

Very unlikely you blew a seal, that's basically impossible to do. Your issue is likely boiled fluid leaving air in the calipers as you suspect. Do a good bleed and you're set. 400F is nothing for rotors, they see 4 digit temperatures on most race cars.

Sam

Mighty Shilling

Whew...thanks Sam. I'll do a good bleed tonight. for a bleed like this, should I do the traditional 2 person, or is a pressure bleeder still sufficient?

Techno Duck

Pressure bleeder is the best way, in particular if you have the Motive Powerbleeder. Ive never had much luck with the hand pumped ones.

A 2nd person helps, but make sure they know not to press the pedal all the way to the floor. This will prevent any damage too the seals on the master cylinder. I have heard that you can put a peice of wood or something down below the brake pedal so that this dosent happen.

Mighty Shilling

Good call Techno Duck. I'll go ahead and use the motive power bleeder we have. Thanks for all the help!