On track braking issues

track_addict · Postby **track_addict** » Wed Sep 03, 2014 8:01 pm

Hi guys,

I'm having some issues with my brakes on the track. Basically the car is getting a long pedal. The fluid is bled before each track day and its got Penrite Racing super dot 4 (rated to 311degC). The pedal is hard and high for the first two sessions but becomes very long in the final two sessions. THe car will continue to pull up no issues at all and I usually set my fastest times of the day in the last sessions. The pedal then stays long for 4-5 days after thr track day but then comes back up to where it should be. After the last track day I did a quick bleed and didn't get any air or black, broken down fluid, which has me very confused. The pedal goes long but the car continues to stop, which tells me that the fluid is going bad.

I also seem to be destroying my A1RM's. The pads look glazed and the edges are literally falling apart. Can anyone recommend some other pads which will be good on the street (happy to put up with some noise and dust) but take a hammering on the track. I feel as if this is too much to ask though. I didn't think I was going to wreck a set of A1rm's! FYI I'm getting 480degC on the front rotors when i come in from a session, so I'm probably seeing over 500degC on track.

Car is an SE with A1RM's, Penrite fluid, stock discs and brake lines. Also has semi's, coils, 3" exhaust, seat, BD bar etc. Local track is Mallala which is very hard on brakes.

Any help is very much appreciated.

Ash.

project.r.racing · Postby **project.r.racing** » Wed Sep 03, 2014 8:15 pm

fluid is rated to 311C, rotors and discs are getting 500C+. seems like you might need a different fluid as that heat is transferred to the hub assemblies and fluid.

it is interest though that the long pedal last a few days and then dissappears. weird one that one.

as for pads. trw/lucas pads are rated 0-650C and a friction rating of 0.50.

track_addict · Postby **track_addict** » Wed Sep 03, 2014 8:23 pm

I had a quick search around and couldn't find any other fluid that had a big jump in temperature rating. I could only find fluids around 330degC, which probably wouldn't fix my issues.

A1RM's are rated 0-780deg. I've got some pictures which I can post up to try help out. I'm abit confused as to why the pads have shat themselves as I thought there limit would by way beyond what myself or the car could do.

Maybe Ill just get big AP's

.

Pamex · Postby **Pamex** » Wed Sep 03, 2014 8:24 pm

What master cylinder do you have? What's the fluid level like? Any leaks?

track_addict · Postby **track_addict** » Wed Sep 03, 2014 8:29 pm

Stock master cyl. Fluid level is at full, drops very slowly but I attribute this to pad wear and the pistons pushing further out of the caliper. Leaks, none that I am aware of. Brake lines look in good order and everything is check tightened before a track day.

What are you thinking Pamex?

plohl · Postby **plohl** » Wed Sep 03, 2014 8:53 pm

Braided lines?

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project.r.racing · Postby **project.r.racing** » Wed Sep 03, 2014 8:54 pm

plohl wrote:Braided lines?

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first post says stock

but might be the next step to do.

plohl · Postby **plohl** » Wed Sep 03, 2014 8:56 pm

Yeah, missed that. May as well give different fluid a go. Cheapest thing to try

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project.r.racing · Postby **project.r.racing** » Wed Sep 03, 2014 8:58 pm

track_addict wrote:A1RM's are rated 0-780deg. I've got some pictures which I can post up to try help out. I'm abit confused as to why the pads have shat themselves as I thought there limit would by way beyond what myself or the car could do.

I knew the Ar1ms were rated higher. I just thought i'd post up another pad as you requested.

I dont think it is the pad that is the problem, but the clamping force that is. same scemerio as glazing new pad without a proper bedding in process. i think the ar1ms are just getting destroyed do to lack of correct pressure from piston.

sailaholic · Postby **sailaholic** » Wed Sep 03, 2014 9:01 pm

Have a chat to the guys at brakes direct (or email them this info) and see what they say. Never hurts to get some expert opinion.

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project.r.racing · Postby **project.r.racing** » Wed Sep 03, 2014 9:07 pm

no silicone used to lube parts is there?

davekmoore · Postby **davekmoore** » Wed Sep 03, 2014 9:33 pm

People have been telling me for years I need to do less braking to keep corner speeds up and lap times and massive front brake wear down.

I completely agree with them and now look for passenger rides and tuition whenever I can get them. This is helping.

I've also ordered a kit of Wilwood front brakes and brake ducts as I'm so tired of buying pads and rotors. Hopefully this kit, along with better tyres and more skill and bravery, will solve the problem.

Magpie · Postby **Magpie** » Wed Sep 03, 2014 9:40 pm

I would have not gone with wilwoods but agree with the brake ducts. Getting the brakes cooler will go a long way to managing the fade. A1RM's never had any issues, however I do prefer the Winmax W5's due to their higher temp tolerances.

I'm using NB8B's front rear, stock rotors, rebuilt calipers, W5 front, W3 rear and braided lines.

deviant · Postby **deviant** » Thu Sep 04, 2014 12:44 am

I have used A1RM in the past on a WRX and they were okay for causual track use on road tyres but I found them totally woeful on a modified MX5.

My NB8B has DBA slotted rotors on the front, Carbotech XP12 front and XP10 rear (race only pads really). I use Motul or Penrite RBF600 or 660 depending on what is available. Stock rubber brake lines and stock master cylinder are in place and there is no ducting beyond the stock heat shields. My car also has semis, coilovers etc.

The thermographic paint burnt off the brake discs a long time ago which I believe happens at a sustained 660c or something. With the above setup I can run lap after lap without the pedal going long or the brakes fading, they also work within 2 corners on sprint type events. My discs are barely worn and the same pads have been in the car for two seasons.

Your pads are glazed and falling to pieces because they are operating outside of their range. Try something like the Project Mu club racer or see about the lower spec carbotechs if you use the car on the road.

The pedal going long and then coming back is possibly an internal leak in the master cylinder...if you press and hold hard on the pedal does it slowly sink?

davekmoore · Postby **davekmoore** » Thu Sep 04, 2014 2:00 am

Maybe the ducts alone would have been enough to keep temps down, thus not needing to use such aggressive pads?

DBA slotted front rotors worked well until they got scored by Project Mu front pads which wore down to the metal within one track day. They were then totally FUBARed by the Hawk Blues, which were also down to the metal after one track day.

So maybe the Wilwoods will be overkill, but that's ok if they reduce my consumables cost.