When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi! I drove a C7 GS manual on track. I just bought the car and did a brake fluid change at my local shop. They only used about 0.7L of the castrol SRF and they said it is finished. However, after pushing 15mins on the track, my brake failed. I heard a liquid squeeze sound (seems like air in the liquid). Then I lost the brake. When I press the brake pedal all the way down, I only have 10% of the braking force and it feels super soft. After let the car sits for a few hours, the brake is hard again. What would the reason be?
1. The shop didn't bleed it correctly? Does it need to be an abs bleed or just manually press the brake pedal is enough?
2. 0.7L of castrol srf is not enough?
2. I braked too hard and abs came out? But I don't think this will be an issue.
3. Other brake component is wrong? I don't think so.
I called the shop and they said they didn't do anything wrong. They are not willing to flush again for free. I guess I will do it myself then
SRF boiling is a long-shot, especially after only 15 minutes on the track. The fluid's wet boil point is 518 degrees (F) and dry is 608 degrees (F).
It's more likely they used a lesser fluid than SRF or they didn't bleed properly, leaving air in the lines. Either way, another (proper) flush with tthe correct fluid is needed.
Last edited by NortonCO; Apr 17, 2025 at 09:22 PM.
Didn't bleed properly and I'd say that little amount of fluid was not enough. In addition, if you're a relatively fast driver (high Intermediate or above) and didn't switch the mode on PTM to at least Sport 2 or Race, you overworked the living daylights out of the brakes and that contributed to the fluid boiling. When not in one of the two aforementioned modes, many people that are new to the car have no idea how much the brakes are working behind the scenes until the pads fade or the fluid boils. It also kills rear brake pad life.
Regarding PTM and picking modes....A lot of people pick a mode and then press the button on the console believing that this selects the mode they see on the IP when in fact pushing the button takes it out of the mode you think you selected.
I use SRF and I have (on the front brakes) titanium shims to reduce heat transfer from the pads into the caliper. I've never had an issue with SRF boiling. I use SRF fluid and Carbotech pads...XP20 in the front and XP12 in the rear.
SRF boiling is a long-shot, especially after only 15 minutes on the track. The fluid's wet boil point is 518 degrees (F) and dry is 608 degrees (F).
It's more likely they used a lesser fluid than SRF or they didn't bleed properly, leaving air in the lines. Either way, another (proper) flush with tthe correct fluid is needed.
Absolutely this. Unless you are an absolute clodfoot with the brakes, it’s pretty hard to believe you actually boiled SRF if it was bled in properly.
Do you left foot brake with automatic tranny? Did you smell brake pads? Smoke, maybe even fire? You may want to have a dealer that knows how to completely flush the fluid through the entire system, ABS module included using tech equipment. Perhaps the shop let the reservoir go dry. But as others have offered, SRF is very good fluid and not very susceptible to boiling.
It takes far more than 0.7 liter to completely purge the system of old fluid. Van Bortel did the complete purge for me due to age of fluid/car. I think it was 2 or more liters. Old fluid is crap on the track; that is why most clubs put system purge in their requirements before event.
Ken
Castrol SRF Failed on Track. Need Help!
