Solution for brake bleeder fluid seepage during track use
08-30-2016, 02:29 PM
#1
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Solution for brake bleeder fluid seepage during track use
Some Corvette owners have found an issue with brake fluid seepage from the brake bleeders after track events. The following is a response from one of my contacts within Corvette quality control regarding this condition:
I presume you are also following the recommended track use directions found in the owner's manual, but am posting them as a reminder for those tracking their cars.
We have some of our Corvette owners who track their vehicle and they have brake fluid seeping from the brake bleeders after a track event. There is a simple answer for this condition. When the brake fluid is changed to DOT4, there is left over brake fluid in the brake bleeder. Once the brakes heat up, the brake fluid left in the bleeder boils and seeps out from under the rubber cap. To correct this condition, the remaining brake fluid should be flushed out by using brake clean and air pressure. Once the bleeder is clear of brake fluid, they can reinstall the bleeder.
Brake Fluid
Replace existing brake fluid with a qualified high performance brake fluid from a sealed container. Brake fluid with a dry boiling point >279 °C (534 °F) is qualified. If high performance brake fluid is used, replace it with GM approved brake fluid before driving on public roads. If high performance brake fluid is in the vehicle and the age of the brake fluid is over a month old or unknown, replace the brake fluid before track events and competitive driving. Do not use silicone or DOT-5 brake fluids.
Replace existing brake fluid with a qualified high performance brake fluid from a sealed container. Brake fluid with a dry boiling point >279 °C (534 °F) is qualified. If high performance brake fluid is used, replace it with GM approved brake fluid before driving on public roads. If high performance brake fluid is in the vehicle and the age of the brake fluid is over a month old or unknown, replace the brake fluid before track events and competitive driving. Do not use silicone or DOT-5 brake fluids.
08-31-2016, 01:34 AM
#2
Melting Slicks
I like how they want you to change back to GM fluid. Always trying to get us!
I had some brake fluid seepage. And it would happen every session. No bleeding in between sessions. I have since changed those calipers myself since the dealer would not replace the caliper.
I had some brake fluid seepage. And it would happen every session. No bleeding in between sessions. I have since changed those calipers myself since the dealer would not replace the caliper.
08-31-2016, 03:06 AM
#3
Sr.Random input generator
I thought this is common knowledge : ) It happens on every car.
Anyhow, if you don't have air, you can use a water sprayer and use it to flush the brake fluid out of the bleeders; this is what I used to do before I got a compressor. It will still boil at the track, but what bleeds down will be diluted and will not damage the caliper paint.
Anyhow, if you don't have air, you can use a water sprayer and use it to flush the brake fluid out of the bleeders; this is what I used to do before I got a compressor. It will still boil at the track, but what bleeds down will be diluted and will not damage the caliper paint.
Last edited by X25; 08-31-2016 at 03:07 AM.
08-31-2016, 10:04 AM
#4
Melting Slicks
For those of you having issues with brake fluid 'seeping' from the bleed adapters at a road course, and I'm not just talking about the 1-2 ml that would remain in the bleeder after a flush, please see my response in this thread, post #17:
https://www.corvetteforum.com/forums...ad-course.html
https://www.corvetteforum.com/forums...ad-course.html
08-31-2016, 10:45 AM
#5
Le Mans Master
Interesting.
If there is some residual fluid in the "tunnel" of the brake bleeder nibble, then a little water and drying them out may suffice. Perhaps that is the issue.
IMO If not, then the only place it could be seeping would be along/ through the treads of the brake bleeder nipple. Baring that the brake line rubber/ steel/ crimps are A-O-K.
I believe I had read some have applied plumbers tape to the threads before tightening.
Else, over tightening which may have deformed the caliper or nipple seat could be the issue. Blue print or replace seems the option there.
I guess the last area to suspect would be the seals at the caliber pistons. Baring the caliper is sold.
Interesting good luck resolving.
Let us know.
If there is some residual fluid in the "tunnel" of the brake bleeder nibble, then a little water and drying them out may suffice. Perhaps that is the issue.
IMO If not, then the only place it could be seeping would be along/ through the treads of the brake bleeder nipple. Baring that the brake line rubber/ steel/ crimps are A-O-K.
I believe I had read some have applied plumbers tape to the threads before tightening.
Else, over tightening which may have deformed the caliper or nipple seat could be the issue. Blue print or replace seems the option there.
I guess the last area to suspect would be the seals at the caliber pistons. Baring the caliper is sold.
Interesting good luck resolving.
Let us know.
08-31-2016, 12:38 PM
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08-31-2016, 11:26 PM
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Here's some additional feedback that I received today...
Re-torquing the caliper bleeders when the caliper is hot can damaged the caliper. It is also possible to damaged the threads and seat for the caliper’s bleeder. Torquing the bleeders should only be done when the caliper is at room temperature. The torque values are listed in the service manual that dealership service departments use.
In my experience, the bleeder seepage is usually due to a small amount of fluid remaining in the bleeder column after it’s tightened. It gets hot, expands, and weeps out of the top of the bleeder. Flushing with a small amount of water or a mild brake cleaner helps. Brake cleaners cannot come into contact with the carbon-ceramic discs from the Z07.
In my experience, the bleeder seepage is usually due to a small amount of fluid remaining in the bleeder column after it’s tightened. It gets hot, expands, and weeps out of the top of the bleeder. Flushing with a small amount of water or a mild brake cleaner helps. Brake cleaners cannot come into contact with the carbon-ceramic discs from the Z07.
09-01-2016, 05:20 AM
#8
Melting Slicks
When my z51 calipers leaked. Dealership replaced one when I had clear evidence on both. I added a small portion of thread tape on each bleeder and never had an issue beyond that. I just added z06 brakes and did the same for preventive measures.
09-05-2016, 07:21 AM
#10
Melting Slicks
I feel bad for Bish and he's the guy with the real issue here. This would be utterly frustrating. Easily solved if he had the iron brakes and just move on to an AP Racing setup. But having invested in the CCMs, I'd be pretty darn frustrated with GM. Coating your whole caliper and wheel in brake fluid is not the same as 1ml of fluid boiling out the top of the bleeder nipples. Anyone who has tracked their car and maintained their own brakes knows that instantly.
Last edited by spearfish25; 09-05-2016 at 07:22 AM.
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