Let's Talk Track Brakes |
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Let's Talk Track Brakes |
jdogg |
Aug 10 2007, 08:09 AM
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#1
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Member Group: Members Posts: 431 Joined: 28-January 03 From: Youngsville, NC Member No.: 204 |
OK, so I've had my car for almost 6 years now, and it has been through a LOT of changes over those years...It started as a stock class 2.0 AXer, then to street prepared, the to SM2 with the addition of the -6. I had done a smattering of track events over those years, primarily focusing on AX, but last fall the track bug bit and bit hard!! I've done about 8 of 'em since October last year, and just can't get enough.
But this brings me to my question(s)/issues. As my driving is improving, I find I am being much harder on the car (a good thing), but some issues are coming to light, most notably the brakes. I have the much hyped 914club billet hubs on my car, utilizing M calipers, SC vented (not cross drilled) rotors, Carbotech XP10 racing pads, brand new 19mm MC, etc. The brakes work very well...once the pads get some heat in them they will stick your eyeballs to the windshield with no fade issues. The issue I am having with this set up is the pedal softening and the travel growing after a couple sessions. At first I suspected the MC, so I replaced it...then after bleeding the system and leaving it under pressure with my power bleeder, I noticed some fluid seepage around the RF caliper. The calipers were rebuilt last fall and have about 8 track weekends on them, but I went and got a new rebuild kit and rebuilt it. I thought that maybe that was a potential source of air and a possible reason for the pedal travel issues. I spent the past weekend at Carolina Motorsports Park (CMP) in lovely east bumfuck middle of nowhere no cell service one stoplight Kershaw, SC. A very challenging layout, tight and technical, and very hard on equipment with a lot of hard braking zones, so I figured it was the perfect venue to test out my brand new MC and freshly rebuilt caliper and see if I could keep a pedal all day long. After session 2 on Saturday the pedal travel had indeed moved again. So I bled the brakes (heel and toe with a low brake pedal is nearly impossible) and the pedal came right back where it needed to be. I resigned myself to the fact that I was just going to have to bleed 'em every two sessions. Well, it was successful, uneventful rest of the weekend with plenty of bleeding (although it was hot, really fucking hot...103 on Sunday with lots of humidity). Fast forward to Monday night when I go to unload the car from the trailer....no brakes!!! WTF?!?! Seem I have blown the left front caliper out now too, and this one leaked fluid all over the damn place.... So does everyone need to bleed their brakes that often to keep a firm - high pedal? Is rebuilding calipers every 2 or 3 events whether they need it or not going to need to become a regular maintenance item? Is there a better way? |
914forme |
Aug 10 2007, 01:50 PM
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#2
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Times a wastin', get wrenchin'! Group: Members Posts: 3,896 Joined: 24-July 04 From: Dayton, Ohio Member No.: 2,388 Region Association: None |
SS Shims, and add some heat sync coumpund to them on the pad side. Or pad compound copper ceramic SS ceramic then ceramic and piston. You want to have fun add a computer style heat sync out the top. As long as you have wheel clearance. You coud add water cooling by shooting water mist at then. You could use the computer heat syncs that are water cooled also.
The J-class racer ran Mid-Ohio, Putnam, IRP, and a few other Robeling Road and Elkhart. All stock, except good fluid, and Ducts on the front. Never had issue, though a stock 2.0L can only push you so fast so the braking zone for others was non existant for us. The front brake coolers where a piece of al pipe with a mount that fit over the rotor with a small air foil built in. I shoud have painted a coke logo onto it cause it looked very simular to a Coke/beer can. The area you are in, look at your Nascar builders for cheap take offs, those guys need to cool brakes way more than you do. And the hand me downs are cheap!!!!! |
jhadler |
Aug 10 2007, 02:23 PM
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#3
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
SS Shims, and add some heat sync coumpund to them on the pad side. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/blink.gif) The shims are to reduce the heat transfer, not improve it... The last thing you want to do is add some kind of thermally conductive paste to the system... QUOTE You coud add water cooling by shooting water mist at then. And don't forget to replace your rotors after every race as they will be hideously warped at the end of the day. (IMG:style_emoticons/default/biggrin.gif) Still, it'd be really cool to make water cooled brakes like the European truck racers do. The front of the car would spout steam every time at the end of the straightaway. Really freak out the competition... -Josh2 |
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