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Just did a track day, now I have brake questions (kinda long)

Just did a HPDE at MSR Houston November 19, 2017. Had a blast and I think I'm starting to drive the car now instead of the other way around.

I had three pucker moments while hitting the brakes at 120 mph. The brake pedal went to the floor, slowly at first then got progressively worse. Bad enough I had to cut the session short.

My set up is as follows:
Stock 4 piston Brembo up front with Pagid RS29 pads that are about 1.5 years old. The car is mainly street driven with 3-4 HPDE events in that 1.5 year time span. Maybe 6000 miles on them.

Motul RBF 600 fluid. Freshly flushed two days before this particular event with three bottles.

14" rear Shelby brakes with Stop Tech Sport pads. These have 1 HPDE event and about 3000 miles on them.

What I don't have are brake ducts. I know, I know, shame on me.....

My question. Will brake ducts prevent this?
My 2018 plan is to do the S550 6 piston swap. Do I use the same ducted backing plate for the 15" rotors as I would for the stock rotors?

The way it acted, I boiled the fluid. The pedal would come back. The pedal NEVER got hard. I am of the understanding that a hard pedal is pad fade. Is this correct??

Thoughts and constructive criticism accepted. Thanks for reading......
The Houston area is one of the most humid areas in the country. You should thus consider going to something like Castrol SRF, which apparently is quite a bit more resistant to boiling when "wet" than most fluids (which is why it commands a price premium). Yeah, it'll cost more for a fill, but it may be worth it if you are fighting soft fade like that.

But ducts come first.

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Something doesn't sound right, fresh fluid and good pads should not have caused you to loose the pedal like that. I have same set up without ducts cause I could not get 2012 kit. Using the GT500 front shields up front (basically just a little tie rod heat shield) and no shields on rear with GT500 rotors. Run at MSR Cresson and go all day without any issue.

Grant 302

basic and well known psychic
It could have been air in the fluid that lead to a boil over too, but lower temps could or should still have prevented it. At the very least, reduced or delayed the issue.

But just because *you* aren't having a problem, it doesn't mean somebody else can't boil the fluid at the same track, even with the same setup in 100% working order. And that can be for good and bad reasons. Bad technique like braking too early and too long or good technique - just driving the ____ out of it. Brake ducts would help with either.
Love the banter back and forth on this but I think the bottom line is heat is the enemy. Bleeding the brakes before every track event is a must. Only takes a few minutes and you'll never be sorry. Store your extra brake fluid in the container and I put the container in a gallon ziploc bag to keep out any excess air (maybe overkill but I can afford the extra $.50 for the bag ;)).

The titanium shield will protect the caliper seals from the heat and I use these religiously. Just bought an extra set (can't remember where) but they're worth it.

The Brembo's that are stock are plenty of brake for 120mph. I haven't had any issue with them not being enough brake. I do use different pads at the track than on the street. A lot of us will differ on what to use and we may start a religious war on this one. I use DTC-60's on the track and HPS on the street. If I'm at a smaller track where I don't get that much speed (under 120) I use HP+ as I just don't need as an agrressive a pad as the DTC-60's.

Rotors should be cleaned and possibly sanded with 130 grit paper if you swap pads as some of the chemical compounds might not mix well between pads.

I know I've gone on and on here. No reason for braking issues on these cars at 120mph even with a somewhat stock setup (OEM pads will burn up pretty quick). Fade and squishy pedal feel is 100% heat related either in the fluid (most likely) or pads that have given up.

Just my 2 cents.


Cooling ducts are an HDPE requirement. Also adding titanium shims will prevent cooking your piston boots.
SRF fluid is most likely a good idea in humid Houston. Yes it costs more, but so does trading paint with other things on the track.
As a minimum, install ducts and and a good fluid bleed before your next event.
My guess is you had a air bubble in the brake line introduced during the flush and as everything heated up, it made the issue worse. Took me a few days (and 2 flushes) to get all the air out after installing a new master cylinder. If you don't have a Motive power bleeder, I highly recommend one - Much less mess, can bleed the system solo and ensures no air in the lines.

I cant imagine 2-day old Motul MBF 600 didn't hold up. I have been using it for years, trouble free (before and after I installed cooling ducts). More expensive brake fluids last longer (Wet Boiling Point rating), but fresh fluid (Dry Boiling Point) is within a few degrees on most high performance options. Castrol SRF is by far the leader in "wet" performance and has superior ability to take on moisture\contaminates while still being effective. If you flush before HPDE, Motul is a good choice. For your reading pleasure -

And +5 on getting cooling ducts installed ;)

Norm Peterson

Corner Barstool Sitter
Exp. Type
Exp. Level
5-10 Years
a few miles east of Philly
Love the banter back and forth on this but I think the bottom line is heat is the enemy. Bleeding the brakes before every track event is a must. Only takes a few minutes and you'll never be sorry. Store your extra brake fluid in the container and I put the container in a gallon ziploc bag to keep out any excess air (maybe overkill but I can afford the extra $.50 for the bag ;)).
I take this one step further and use a piece of plastic bag over the bottle opening before putting the cap back on (I don't fully remove the original seal either, and flatten it out over the opening as well). Then it all goes in the ziplock bag.

Exp. Type
Exp. Level
3-5 Years
Irvine, CA
Since we're on the topic of the brake cooling ducts, I experienced pad fade on the OE pads with brake cooling shields during my last HPDE so it looks like I need the ducts as well. For those who bought the ducts/kit, did you buy the Blowfish kit or is there still a Ford Racing/Performance kit available? I didn't see one on the Levittown Ford parts website and I can't access Ford Performance at work.

Also, I know there have been many threads about pads, but since I will need new pads soon anyway, pad recommendations would be appreciated as well!
I don't daily the Boss but I go for a hard canyon/mountain road drive once or twice a week, and I don't want to have to swap pads for the track/street. Basically stock, just the brake cooling shields, tranny cooling scoop, and square tire/wheel setup (most likely going to NT01s 275 square on 18x10s) with a few smaller RSB options so I won't be generating the highest braking forces possible.

Thanks guys!

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