FasterIsBetter

This was posted on the Z06 forum and suggested I post here as well, since more folks here have experience with track use and BBKs:

Last summer, I had Wilwood brakes and rotors installed on my 2004 Z06 primarily for use at HPDE and track days events. The calipers are the 6 piston fronts, 4 piston rears, narrow calipers (not the LG wide calipers, which was probably my first mistake). The fronts are the Wilwood kit that fit the stock 17" wheels. I'm using Wilwood calipers, pads, rotors, brake lines and even Wilwood 600 brake fluid.

After having them installed, the slotted and drilled rotors that were used cracked at the first event I used them at, up at Lime Rock. I replaced them with Wilwood slotted only rotors (not cheap). Then at a 3 day track event at Watkins Glen over Labor Day weekend, the brakes seized on me. The front calipers seized on the rotors and could not turn the front wheels. Breaking the bleed valves open did not release them. When the calipers were removed, the pistons were seized in the sleeves.

I called Wilwood right after Labor Day, and the tech person there told me that the O-rings on the pistons needed to be replaced. I got the O-rings, followed Wilwood's instructions to a T, cleaned and rebuilt the calipers, reinstalled. Did one track day in October, and they seemed fine.

The first chance that I had to get on the track this year we a couple of weeks ago. The brakes seemed fine for one day on Thunderbolt at NJ Motorsport Park. Then this past weekend, I did a two day event at Lime Rock again. After just 3 sessions on the track, 20 min. each, the calipers seized up on me again. Removed the calipers, and the pistons are frozen again, and show signs of scoring. I freed up the pistons, reinstalled the calipers (lost the whole afternoon in the process). Next day, did a couple of sessions in the morning, and they froze on me again. Fortunately, I trailer to the track, so was able to get home.

I called Wilwood this week, and I'm sending them the calipers to check and hopefully repair. But I was wondering if anyone else has had similar problems with the Wilwood 6-pot fronts. If so, what was the problem and how was it resolved?

Much appreciated.

Steve

Note:
I did not experience pad taper, in case someone thinks that's the problem. Pads have worn straight and true, as have the rotors. At this point, I'm thinking of going back to the stock Corvette brakes/rotors with Hawk pads, and just bring spares to the track, in case I need them. Frustrating that I've spent all this money on Wilwood brakes and having all these problems. I could have bought a ton of stock pads and rotors for what I've spent on these damn Wilwoods.

WBHighwind

Was it all 6 piston that siezed and/or was it the same pistons both times?

I have the GStop kit and have had no issues with it whats over besides them making me want to get new wheels.

redtopz

That sucks! If I were you I would tell Wilwood to keep the calipers you sent back and send you the wider ones that come with the G-stop kit. Sounds like they just can't take the heat from track use. No sense risking seizing up again when you spend so much time and money going to track days IMHO. You also might want to consider some cooling ducts if you don't already have them.

CHJ In Virginia

I also have the G stop kit and have run the snot out of it without problems. I would get Wilwood to exchange the calipers in front for the SL-6 ones that are used in the G stop kit. That should solve your problem. That type of product problem is unexcusable.

Sidney004

I am not a Wilwood expert at all(or any other kind for that matter!) but if the bores are out of tolerance(undersize) or the pistons are out of tolerance(oversize) it could happen as the caliper heats up and components start expanding. You are never going to see any scoring on the bore because the dimensions between the bore/piston are designed to compress the o-ring within its working range, there is always going to be diametrical clearance unless the piston gets cocked. They should replace that caliper, something is amiss.

Bill Dearborn

I have been running the LG kit since 2005. I have never had any problems with the pistons seizing. I know other people who have the kit you have and they haven't mentioned any problems similar to yours.

Bill

John Shiels

when you pulled the pistons what did the o-rings look like? Do you have ducts? Pistons aluminum or SS?

Darkness

Calipers for sure are flexing and "kinking" the pistons on there. You might have galled the bores already and its not really a seal issue. Another problem might be the different expansion rates on the materials. Aluminum body and steel pistons and going to grow differently. And I dont think wilwood uses piston caps like the racing brake companies do. I've had similar issues with AP calipers, and always had drag.

The solution is selling that kit on the honda forums and getting a good brake kit.

ryan0

how did you remove the pads?

I just got a set and noticed the pads fit TIGHT. I even had to grind them down to get them in.

Is there a chance the pads cocked a little bit and seized?

96CollectorSport

I know exactly what is happening to your brake kit, I had it happen to two brake kits I installed about 3 years ago. Wilwood had a batch of these calipers that were not anodized, the pistons are gauling inside the bore. We went through hell getting Wilwood to admit that they made a mistake. After several thousand dollars worth of rotors and many frustrating phone calls we sent a caliper back to Wilwood and they took a look at it and found out the pistons were gauling and sent us replacement calipers.
If you have any problems feel free to PM me and I will do what I can to give you the specifics.
Joel

Wicked Weasel

I have no issues with my wilwood kit and now thanks to nordlocks from gary they are very easy to setup. The pads are tight to get in but if pistons are fully retracted they fit.

Steve if you don't get answers let me know and I will try to help out.

ryan0

I meant height-wise. Where those silver metal shims are.

I test fit the street pads that came with the kit and had to hammer them in and pry them out. The Carbotechs had some of the pad material outside the edge of the backing plate. I had to grind it off to even get the pad in.

Sidney004

If they didn't anodize the bores and there was galling you should be able to see surface imperfections on both the piston and bore. That could be it.

Bill Dearborn

The Wilwood pads do not have any material outside the edges of the backing plate. Here are some pictures of a new 7420 H pad.

Bill

ryan0

i said the wilwood pads were super tight... the carbotechs had pad material outside the backing plate... THEY didnt fit at all.

Bill Dearborn

Misunderstood your post.

Bill

FasterIsBetter

Very interesting. Sounds like this could be the source of the problem, at least in part. As I said, I had the LG G-stop kit on my prior 2003 Z06, and those brakes worked beautifully, never a problem.

GAS2

STOPTECH. PERIOD!!!!!

FasterIsBetter

Does Stoptech make a caliper kit that fits the fronts with 17" rims? If I have to go up to 18" rims for the front, there are lots of options available. I elected to stay with 17" because I already had two sets of rims and tires, and didn't want to spend a fortune buying all new tire/rims to go BB.

RedLS1GTO

I have been asking the same question on every forum I can think of for the last month and it looks like the Wilwood kit is the only 6 piston that will fit with a 17" wheel. I have been looking for a C4, so I might have missed something C5 specific along the way.