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 siezed on me. The front calipers siezed 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 siezed 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 siezed 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

 

Far better to take this to the autocrossing and racing forum in the general section. There is a lot more experience over there....

 

I agree with Solofast. Post that in the track section.

My first questions would be. Are you running brake ducts? All the way to the spindles? Do you bleed off some of the brake fluid after a day or weekend? What Wilwood pads are you using?

Running drilled rotors on track is a bad idea. They crack fast. Blanks are better. Slots if you have no choice. Never drilled.

 

Couple of thoughts Steve:

Drilled rotors should not have been part of a kit for your intended use from the start. The GT rotor the far better choice. Costly process, so those reading along please be sure you convey your intended use to your supplier to avoid this type of problem

The BSL6r caliper is not the top choice of caliper for hard track day use. While it's a good street part and with proper pads will endure a day of spirited runs at the track it's simply not durable enough for sustained open track applications. Lighter body construction, thinner pads and lower overall mass are not ideal for hard use.

What pads were in use on this at the time? I ask as I'm curious to the pad wear rate, heat generated and pressures the caliper was subjected to. While I openly tell you that this is not the ideal combo I have a customer who has beat on these calipers in ways I'd never condone. A Dodge Magnum running sub 1:50 at Laguna Seca who went through rotors about every two events....having finally moved him to the W6a caliper I personally looked over the old BSL6 parts with two seasons on them, fit new seals to them and passed them along to the second owner he sold them to without question. The powder coat was begining to burn off of them! (don't worry he sold them cheap)

Having dealt with this caliper for years on many cars I've never seen on just 'seize' up. What I have see however is a lot of poor pad choices that lead to excessive pad and taper wear. This ***** the pad in the caliper all silly and causes the pistons to bind in the bores and not retract. The problem grows, the taper gets greater and piston to bore compliance is lost with a lot of piston extension. (thus the reason for pad wear spacers)

The only problems I've seen on these were a leaky seal or cracked piston.

 

Todd,

You and I had spoken about this problem last fall, and if you recall, I bought the pads and replacement rotors through you, as the original rotors were the wrong size (stock 12.9" rather than the 13.06" that this setup requires). I think I got the O-ring kit from you as well.

I'm really concerned about the performance of these brakes. I'm tempted at this point to go back to the stock Corvette calipers and just carry lots of extra pads and rotors to the track with me. The stock brakes worked fine, I just was burning through pads and rotors like crazy.

The problem is not pad taper. The pads are wearing true, not tapered at all. And I'm running the GT rotors at this point, not drilled.

It is frustrating to have spent so much money on these damn brakes, rotors, pads, etc., and not have outstanding performance. For what I spent on all this stuff, I could have bought a hundred sets of stock rotors and Hawk brake pads. Oh well.

Steve

 

Thought that was you. I can't offer any more insight about the binding or seizing comments however. I can honestly say it's not something that's come to me much at all. Usually related to pad wear as I mentioned. Also seen a few cracked pistons. Let me know what they tell you.