I was at Thunderhill yesterday and a red flag was thrown at the end of the back straightaway.
I was clocking 135 when I saw the flag and just barely managed to get it stopped at the end of the straight.
I sat there for about 10 minutes while the track was cleared with my foot off the brake so the pads could cool. When I got back to my pit the pedal hit the floor.
Apparently the fluid boiled while we were sitting there which didn't surprise me after a panic stop like that and no cooling from the rotors sitting still.
What I didn't expect was that the brakes we dragging heavily. I let them cool and pulled a rear wheel and opened a bleeder.
No fluid came out but the wheel turned freely again. Today when I unloaded the car they were dragging again.
I put the car on the lift and all 4 wheels are dragging significantly. I backed off the master at the booster to be sure the push rod wasn't hanging the master open a little bit. Nope.
I then cracked the lines at the master and the exit lines at the ABS unit and no fluid came out and the wheels still drag. WTH is hanging them up?
[font=verdana, arial, helvetica, sans-serif]If there was residual pressure I would expect fluid to spurt out when the system is opened.[/font]
I will pull the wheels and inspect everything more closely this week, but WTH?
I have boiled fluid before a few times but not on an ABS car. What is going on here?

Wow that's strange. I have no idea what is going on but I'm in to find out what happened. Good luck with the fix.

All pistons seized?
Highly unlikely, but possible.

out of curiosity, what upgrades if any are done to your braking system?

I would start with bleeding the brake system, and changing out the brake fluid. I would think that when the BF boils, it would be in the caliper area and you would also have some expansion.

I've not experienced this type of event so I'm very interested in learning what you find as the cause of failure.

Good luck with your repair,
2HP

That sounds weird. What brake fluid did you have?

I would pull the calipers and look at the seals, they may have melted.

I assume the M/C was still full? You said no fluid came out when you opened the bleeders? If you have a power pressure bleeder I would open up all the caliper bleeders and see if you can flush out the whole system. If that doesn't work then I would suspect either the proportioning valve or ABS manifold might be involved, also look at the soft lines to see if they have collapsed but that's unusual.





BTW as a 25 year SCCA flag/com guy a red flag doesn't mean a full lock up or abs panic stop as the behind you might not have brakes a good as you. (I have seen metal to metal like this more than once) Come to a controlled safe stop (off line) within sight of one of the corner stations.

k98dave said:

I assume the M/C was still full? You said no fluid came out when you opened the bleeders? If you have a power pressure bleeder I would open up all the caliper bleeders and see if you can flush out the whole system. If that doesn't work then I would suspect either the proportioning valve or ABS manifold might be involved, also look at the soft lines to see if they have collapsed but that's unusual.


BTW as a 25 year SCCA flag/com guy a red flag doesn't mean a full lock up or abs panic stop as the behind you might not have brakes a good as you. (I have seen metal to metal like this more than once) Come to a controlled safe stop (off line) within sight of one of the corner stations.

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I have tilton racing fluid, so it's good fluid. A buddy tells me it's the ABS module and to switch it out with the FR500 one. When I get some time this week I will flush the system and check everything more thoroughly.
I just did a quickie inspection to see if it was anything obvious and to get me some information to ponder.
YES you are right about panic stopping. It was at the end of a long straightaway with a very sharp blind right hand 90* corner. For all I knew the crash could have been there so I stopped where the other cars stopped.
I was just carrying a lot more speed at the time. Damn these brakes worked well for what they are.

Shaun12 said:

out of curiosity, what upgrades if any are done to your braking system?

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Baer 6 piston Pro+ up front with DTC 60 pads and Super Snake brakes in the rear. 14" rotors, GT500 calipers and good pads (forget the number) and braided lines.

Get the FR500S ABS distribution block and controller module if you don't already have that.

Once that's done, take it to the dealer (unless you have IDS software), and have them do the ABS power service bleed procedure on it.

I would definitely consider taking the calipers off and making sure the pistons aren't seized, as well.

I was there as well, and got red flagged right at T14. I could see the track clean up. I guess a Corvette blew up his motor and dumped oil all over the track. They were laying down whatever they use to clean it for a good 50 yards in the T6-7-8 complex. I guess he put a piston through the block.

@Fabman don't mean to hijack your brake thread..that's really strange. Hope you get your issue figured out!

ArizonaBOSS said:

Get the FR500S ABS distribution block and controller module if you don't already have that.

Once that's done, take it to the dealer (unless you have IDS software), and have them do the ABS power service bleed procedure on it.

I would definitely consider taking the calipers off and making sure the pistons aren't seized, as well.

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I am ordering the module today, but what's different about this dist block?

mprichar87 said:

I was there as well, and got red flagged right at T14. I could see the track clean up. I guess a Corvette blew up his motor and dumped oil all over the track. They were laying down whatever they use to clean it for a good 50 yards in the T6-7-8 complex. I guess he put a piston through the block.

@Fabman don't mean to hijack your brake thread..that's really strange. Hope you get your issue figured out!

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Ah...yes there were two cars in front of me.
One was that wickedly fast BMW with all the aero and another one I don't recall what the other one was......
Didn't you say you were bringing a Miata?

Fabman said:

Ah...yes there were two cars in front of me.
One was that wickedly fast BMW with all the aero and another one I don't recall what the other one was......
Didn't you say you were bringing a Miata?

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Yup, I was in the black Miata #302. I was the first car in the red flag train at T14. That TC Design BMW was INSANE haha.

mprichar87 said:

Yup, I was in the black Miata #302. I was the first car in the red flag train at T14. That TC Design BMW was INSANE haha.

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He had nothing for me on the straights but he caught me real quick going into that real tight corner on the back half so I waved him by as soon as I saw him in the mirror and boom, he was gone.
Usually cars in the mirror are going the other way I remember seeing that Miata with the 302 on it....

mprichar87 said:

Yup, I was in the black Miata #302. I was the first car in the red flag train at T14. That TC Design BMW was INSANE haha.

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That's a win right there.

Fabman:
Sounds like you should (plan to) do a full rebuild and flush of everything. Or at least I would. Starting with the fronts, until you find the culprit. I'm surprised the reservoir didn't puke any fluid with boil over at all four corners.

Grant 302 said:

That's a win right there.

Fabman:
Sounds like you should (plan to) do a full rebuild and flush of everything. Or at least I would. Starting with the fronts, until you find the culprit. I'm surprised the reservoir didn't puke any fluid with boil over at all four corners.

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I just ordered the FR500 module and will flush all the fluid out and see what happens.
You have to program this module? Taking this thing to my local dealer is cringeworthy.

I don't think you need to program it, but my understanding is that you do need it cycled like ArizonaBOSS mentions above to bleed it.

Grant 302 said:

I don't think you need to program it, but my understanding is that you do need it cycled like ArizonaBOSS mentions above to bleed it.

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Can't just pedal pump it like i have been doing?
I did notice that my pressure bleeder doesn't work on this car.
I used to have a cool vacuum bleeder that worked killer back in the day. I wonder if that would work here?

IMO, heat soak, the same thing got Roush in trouble a few years ago, came into the pits after running it hard, went out and nailed the wall.