FasterIsBetter

Has anyone done a rebuild on the Wilwood SL6 calipers? In particular, I was wondering if anyone found an easy way to extract the 6 pot pistons. I've used the compressed air trick on smaller calipers, popping the pistons out. But with a 6 pot, it looks a bit tricker, as they all won't pop at the same time, and once one is popped, that's it for the others.

Any suggestions greatly appreciated.


Steve

aggie_corvette

John Shiels

put a block of wood so they don't blow out completely but come out most of the way. Then you can just grab them by hand.

0Randy@DRM

Use 1/4 plywood cut into smaller peices. Then you can blow them out 1/4 inch at a time. That way they will all come out pretty even. Then after one pops you will be able to pull out the rest by hand, like John said.

Randy

Bill Dearborn

I have been looking at the Wilwood web page to see if they have a rebuild kit for these calipers but haven't been able to find one. Is there one or do the parts have to be purchased separately?

Bill

FasterIsBetter

Bill,

They have an O-ring rebuild kit, which is what I ordered. Six o-rings, does one caliper. Two sets needed for both of the fronts. I got the part number from Wilwood tech support and ordered it through Summit Racing. At this point, I'm not planning on replacing the pistons, assuming they are in good shape.


Steve

John Shiels

use brake fluid to lube them on re-assembly not oil. you can also use mica SS or aluminum shims to insulate or as a spacer as the thick pads wear down.

After rebuilding check for weeps from lines and calipers.

0Todd TCE

Caliper rebuilds here are not at all difficult. The key point, as mentioned, is piston removal. The easiest way is to remove the pads and pump the pedal. By design the pistons will come out but very little fluid should be lost if the proper spec caliper is used on the right rotor width. Even a small bit of fluid seepage should allow for all six to be out far enough.

From here remove the caliper, cap the hose (you did think of that, right?) and with the caliper on the bench wiggle out the pistons. Use a pick to pull the seals and then go at it wish soapy water and a nylon tooth brush. Use some scotchbrite on the pistons to remove any burs or markings. Blow it all dry.

Wet the new seals by dipping them completely in brake fluid. (an spray can cap works well) and fit them to the bores. Dunk the exterior of each piston in the fluid also and press it down into the bore. Squarely and it will go with ease. When done be sure the bleeders are closed and with your finger over the inlet fitting thoroughly rinse the whole thing in water to dilute the messy brake fluid. Blow dry and re fit to the car.

Seal kits are sold in ONE caliper package only. Bleeders, pistons, bridge bolts...all ala carte.

BTW if your calipers are rather old you have stamped ss pistons (assuming not therm-lock) and the newer forged ss pistons are much preferred. They'll run you about $12ea.

FasterIsBetter

Todd,

Thanks for the info. We actually used the plywood method, on the bench, with the air gun, and the pistons all came out fairly easily. But considering that the calipers were installed this summer, supposedly new, the pistons were rather a mess. The o-ring seals all appeared to be in pretty good condition, but I'm replacing them all anyway. I'm cleaning up the calipers as you suggested, and giving them a chance to dry before reassembling. The scotchbrite pad cleaned the pistons up pretty well, though a couple of them do show some scoring on their outer edges, outside the seals.

The big issue right now is the rotors. Even though I just replaced the rotor rings in August, three days at Watkins Glen and two days at NJ Motorsport Park have done in the fronts. I'm looking for a less expensive replacement rotor in 13" dia./1.25" width to use rather than the Wilwood rotor rings. Any suggestions?


Steve

0Todd TCE

I added some thoughts on your rotor quest too Steve. As for markings on the pistons, if you don't have them now, consider getting and using some pad wear spacer. These are shims of about .125" thick that are placed behind the pads as they friction materials wear down. The purpose here is to keep the pistons in the bore as much as possible. This in turn keeps piston concentrcity up not allowing the pistons to rock as much compared to hanging them out more.

Personally I stock both .125 and .065 in steel. Ti is nice too but costly. I'd avoid alum however as it's not uncommon for the piston edges to dig into the plate under extreme load.