Brake issue at track....

Today I had the 5th track day since I got the car in January.

I have Hawk HP+ front pads, Hawk Street 5.0 rear pads, this is 2nd track day on the pads. ATE Type200 fluid/fresh bleed. Stock Contis. No issues at all previously with this setup.

Today I had a moment where braking from high speed (~115mph) I hit the brakes and it felt like I had almost NO brakes. The pedal travel felt normal, but it felt like the car went full ABS or maybe that feeling when the pads glaze up. The car slowed to ~70 or so before I went off the track and (fortunately) into the sand run off area.

I drove back to pit in and hit the brakes a few times and they felt normal.

I went out for my final session and the brakes felt normal (although I didnt push it on the straight as before - only about 100mph). No further issues.

Any idea why the hell this would have happened? I don't THINK I cooked the pads as there is not a lot of pad transfer (there is SOME but not an excessive amount). I've head about an "ice mode' on other cars where the ECU is fooled somehow. I dunno but it was not a good feeling! :O

I would guess you overheated the pads, similar thing happened to me and that was the only solution that made sense. How hard were you pushing the car on the track? 10/10ths? Regardless, glad you were able to dump the car safely without finding a wall or anything else!

Sounds like maybe the tires weren't fully up to temp. Also the HP+ is more an aggressive street pad than true track pad,. I would suggest you get a dedicated track pad for the fronts and swap at the track, its not that difficult.

TheShadow said:

I would guess you overheated the pads, similar thing happened to me and that was the only solution that made sense. How hard were you pushing the car on the track? 10/10ths? Regardless, glad you were able to dump the car safely without finding a wall or anything else!

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I was alternating ~2 laps 8/10ths, 2 laps ~6/10ths bc of the car overheating. Very hot ~93 degrees and humid so as you know the car doesnt like that.

This particular event was the first hard braking after a lap of 6/10ths.

Yes fortunately lots of runoff at this corner with big sand trap.

I realize HP+ are not a "real" track pad, but previous experience with them had been good on track in this car, and previous cars on track (ITR and WRX). I figured they'd be better than the stock pads - which had worked fine also. I like using the 1 pad for DD and track (see avatar LOL).

A couple of reasons for this happening...

1. Your tires weren't up to temp or they were overheated. Basically a lack of grip on your tires.

2. Pads are overheated or worn.

3. Boiled your brake fluid.

Same thing happened to me but it was because of reason #2.

ipeefreely said:

A couple of reasons for this happening...

1. Your tires weren't up to temp or they were overheated. Basically a lack of grip on your tires.

2. Pads are overheated or worn.

3. Boiled your brake fluid.

Same thing happened to me but it was because of reason #2.

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Tires seemed fine as does fluid (no pedal issues any of the other laps).

Pads have plenty of life in them (only 1 track day and 1000 or so street miles) so its seeming to me like they just overheated. Just odd to me it happened after an entire lap of me not pushing.

Check the front caliper piston seals. You could have had a momentarily stuck piston. You can sometimes feel you struggle with the braking line. Obviously a true failure would be worse but I say anytime you do heavy track duty you should always inspect the seals (add it to your track checklist). I’ve seen too many crashes...

VSA fully off? i'd pull the pads outs and take a look to see what state the friction surface is in.
i've had a number of brake issues on my FK2R. you need 800c (1472F) all round, and I've cooked a number of fronts that are rated for track use. Tried the DBA 4000t3's with heat point and the red paint strip (630c+ iirc) changed colour so obviously exceeded this. I'm now on sintered pads (CL RC6e) and and girodisc discs, waiting for next month when i'm out on track to test this combo.

one thing i have considered adding to my issues is pad binding. the other pads i've used haven't knocked but these CL's do knock because they are slightly undersized to allow for heat expansion - obviously CL think it's needed. if my maths is right, 800c increase is 0.64mm expansion on steel backing plates. I'm reasonably sure there hasn't been this clearance on my other pads so possible the pad hasnt been able to return correctly and causing it to slightly bind.

It's possible another car in your session had an oil leak and you drove right over the oil while braking. Happened to me before....

To OP, you mentioned the brake pedal felt ok but no stopping power, this eliminates brake fluid boiling. If it boiled, then the pedal will be super soft.

If there were oil on the track, I thought the car would lose control or spin. It's hard to maintain a straight line when driving thru oil.

It's interesting to have your pads overheat all of the sudden especially after a cool down lap. Please keep us posted.