Mongoose

iTrader: (2)

I'd like to upgrade the rear brakes on my car (already 1LE/PBR disc) from the 11.65" to a full 12". Hawks has a kit for 10 bolt rears only and I have a 9 bolt. Does anyone have the correct disc backing plates for a 9 bolt to make the conversion possible?
I know Ed Miller had them at one time but I'm not sure if he's still doing the brake kits these days. Any help would be appreciated.

battmann

iTrader: (9)

Try reaching out to Scott at
https://bigbrakeupgrade.com/

QwkTrip

iTrader: (22)

Why? It's not going to make a stitch of difference if you have the same calipers.

If you want better brakes then put money in calipers.

TTOP350

iTrader: (8)

A lot of people call the 11.65" disc a 12" setup. Such a small amount, if you could find a full 12" rotor, you could almost slot the caliper mount holes and make it work.

Mongoose

iTrader: (2)

Looking to maintain period correct appearance and fill up the wheel a little bit.
I emailed bigbrakeupgrade, waiting for a reply.

91banditt2

iTrader: (1)

If you need to piece together the parts you could source a set of 10 bolt backing plates, weld in the existing holes and re-drill the new pattern to match the 9 bolt flange, that's what I did years ago. You used to be able to get them through GM the 10 bolt backing plates are $15.87 each, I checked GMpartsdirect this morning and looks like they've been discontinued.
right backing plate part #10136854
left backing plate part #10136853

EDIT* I read it wrong you already have the PBR's

LAFireboyd

iTrader: (3)

Scott at BBU is awesome, but I don't think he'll have anything to offer here, other than some excellent advice, which he is always happy to offer.

Ed still lists the backing plates, and it appears that he's cleared up the recent website issues he was having, so ordering online is available again.

Backing plates.
http://www.flynbye.com/catalog/i196.html

He also sells a complete kit, which I know you don't need, but it contains the correct 12" rotor that you'll need, so ask about a pair of those too.
http://www.flynbye.com/catalog/i146.html

The kit Hawk's sells is "not available for 9 bolts." But you can get the correct rotor info there too.

I'm not sure this will be worth the costs and the work involved just to increase the size by .4" diameter. That's less than 1/4" all the way around. Pulling axles, buying parts, etc., but I get it, "just because" is all that matters sometimes.

That said, I think retaining the 11.6" brakes would be the better option, simply due to the retention of the factory backing plates, alone. But if you do the swap, then I'd think you wouldn't have any problem selling those factory backing plates. Just say "1LE" in your ad, and people will be drawn to it, like bugs to headlights on hot, humid summer nights!

Mongoose

iTrader: (2)

Scott replied very quickly but doesn't offer anything. I thought about Ed but wasn't sure he was still doing business after all this time. I bought one of his early C4 front kits several years ago and he even came over for the install. I've known him for years but kinda lost touch with life changes/issues and such. I'll try and contact him and see what he can do.