I have the four piston Willwood's, and when I swap out thin pads for thicker pads (Going in the opposite direction from thick to thin obviously isn't a problem, that takes all of a few seconds to do), I have a heckuva time compressing the cylinders to get the thicker pads in (especially the inner pistons, which are a bit harder to get at than the outer pistons). I've opened up one of the bleeder screws, which helps for compressing the pistons, but its still a chore, especially when going from almost shot pads to brand new pads. Is there a compression tool that works for the dual pistons, without having to take the calipers apart? I was thinking about using two backing plates, and removing the tiny amount of pad thats left on one set, and then using a generic spreading tool, but if there's a better way or better tool I'd love to know...I'm figuring there has to be an easier way, so someone please educate me!

 

There are some large, reverse, pliers out there on the market but I could not find them quickly to post a link. The more common remains the basic screw driver against the rotor and prying against the pad. Opening up the bleeder makes it simpler yet but the caliper should be bled once or twice when done. If you're doing this with pad removed you're probably making more work of it than is required.

*And to prolong life if non-booted you'd do well to blow off or tooth brush the pistons before pushing them in.

 

I've used the screwdriver, but I was afraid to push against the rotor--if thats ok to do, I'll try that. I almost did that out of frustration, but I held off. I'll try that next.

Thanks Todd for the reply--I'll probably be calling soon, as I think I'm due for new rotors. Might consider some wider ones if they'll work with the dynapro's and my wheels, if not I'll stick with .81's.

BTW, I know you've said going from the old JCW kit to the 11.75 dynapro is a lateral move (and for the record, I really respect a vendor who doesn't make crazy claims), but I'm ten times more satisfied with the dynapro's performance over the old JCW brakes, maybe it was a pad issue with the JCW's, but on the track the Wilwoods are significantly better. Thanks!

 

I turn the pad I've pulled out sideways and then slip it back in about halfway, then for the inside pull it towards me to push in both pistons, conversely on the outside I push the pad towards the inside of the wheel wheel. Works great, no issues with lots and lots of pad swaps going back and forth from street to track pads.

Don't forget, one side at a time or the other pistons will pop out.

 

You won't hurt the rotors to much extent if you just use your head.

But...you can't do wide rotors really. Yes I can do some custom ones that would be a tad more (like .850 vs .810 maybe) but the gains vs expense just wouldn't justify it to me. I'd have to measure gap with fresh pads for a final width. (the FSL will do about .940 on a .820 application!)

I have the D and H pads now but the H pads are reeeally tight. The mic out about .650 whereas the D is .635 and the normal pads are only .600 thick. So I know there is not much room to do a lot in the DP.

 

Ok, scratch that idea, doesn't sound like its worth it...I think I'll probably bite the bullet and put in the Way brake ducts; I want to do everything I can to stay on 15 inch wheels.

And thanks gnatster, I'll give that a try, that sounds like it should work relatively easily.

 

i just installed a set of 0.95" custom rotors from TCE. i have the FSL calipers. it was very tight to install a set of brand new poly h's w/ this wider rotor, but i got it done. here is a pic comparing the previous 0.81 rotor (with wear) to the new 0.95" rotor.....




this combo gives more mass than the standard TCE offering while being lighter (less mass) than either the Brembo or StopTech offerings. a good compromise, IMHO.

i have more fun out-braking cars than i do out-running them. in the end, i get by them.....

 

Great job!

For those not up to speed here, normally I use the .810 rotor as it is simply shared with other applications. This one was more of a "one off" deal and is not a normal stock item. The goal here was to boost rotor mass (note the thicker walls) but yet retain the same mounting. It was going to take some shimming and the pad fit would be fully taken up by the new rotor....in the end the goal is greater thermal capacity for longer wear. We shall see...

 

A bit more aggressive with the screwdriver worked just fine. I saved the pads--they're almost down to the backing plates--to use for compression. I don't think I'll open up the bleeder valve again though--I checked the brakes after the pad change, and noticed I had gotten a ton of air in there; it didn't matter as I was going to do a full fluid change anyway (although I flushed and bled a couple of extra times just to be safe), and everything is good now.

I had a bad shudder at the end of my last HPDE--figured I'd warped the rotors--but after changing back to street pads and going through the bedding procedure, they seem to be good again--hoping it was just pad material on the rotors.

Still think brake ducts would make for a nice project over the winter; I love the 15inch wheel/Wilwood combo, and I'll do anything I can to optimize it for performance/durability...

 

Remember that a good cool down lap is crucial to pad and rotor life. Hot spotting from parking will bake a small amount of pad material onto a rotor which can later lead to pulsation issues. Roll that puppy around the paddock if they are still hot.

 

Yep, I've been doing that--rolling it a few feet every few minutes, and trying to get a good cool down lap (I've seen you post these things before and I try to do it carefully). The track I was at last was really tough on brakes, and I'm using the brakes harder as I've gotten more seat time; probably could do better on my cool down laps, something I'll try to be more conscious of next time out.

My next time out is a laid back track day; I think everything is fine, but if I'm getting a ton of pulsations I'll bite the bullet and get new rotors for my last HPDE of the year in September (2 days at Road America, I want everything right for that ).

Thanks for all the help--I'm light years ahead of where I was this time last year!

 

Cool down lap speeds should be slow enough not to use brakes at all for most of the lap but fast enough not to get run over.

 

Also need to remember that with smaller kits such as the 11.75 and 12.2 you are working at a much higher duty cycle also. Larger 13" rotors give you greater swept area and mass. Work within your means.