Howdy Turbo Cats! I've got a riddle for the group.
I bought a set of used Wilwood 4 Piston Rear Brake Calipers (with brackets obviously since there's one in the picture.)
Sooo...what pad shape do these things take? The PO never used them and doesn't know.
V8 Roadsters has a kit that looks similar and uses pad shape 7912, and Flyin' Miata has a kit but I can't tell what the pad shape is for those either. I am not Wise in the ways of brake calipers so I don't know if all Willwood 4 piston rears use the same pad shape or if there are differences. I'd prefer to not get the wrong size pads for obvious reasons.

Front!

Top!

Back!

Bottom!

 

They look like the powerlites I had on my FM rear calipers, which were 7912, yes. Best I can suggest is to buy a set of 7912s from somewhere that will accept returns if they don't fit.

--Ian

 

You can go on Porterfields site and look at the 7912 pad dimensions and cut something it out of paper to see if it is indeed the correct pad.
https://porterfield-brakes.com/produ...ite-type-7912/

You could probably email them a picture of your caliper and Wendy would know. I sent her an oddball pad shape once and she knew what it was and had pads hand cut for it.

 

I do know the set came from V8R originally, if that helps.

 

I chatted with Porterfield's sales folks today and they confirmed those calipers almost certainly use the 7912 pad shape based on the size of the opening and the manufacturer. They also allow returns up to 30 days, so I've got two sets of R4 pads on order (it's the same shipping rate for one or two sets.) Since Six says they came from V8R originally I'm pretty optimistic they're the right pads. Thank you all for the help! I shall soon have a preposterously over-braked Miata. I'm totally good with that.

P.S. Wendy from Porterfield actually wrote a separate email to confirm I really wanted two sets and not just two calipers worth of pads. Between this and the bang-up job they did in correcting my previous order I am really impressed with Porterfield's customer service!

 

Got the pads on Saturday and finally got a minute to check fitment - looks to me like they're the right ones. One more step towards stupidly overpowerful brakes!


Looks like they fit!