So, I decided to finally upgrade my 1986 Trans Am's brakes. I ordered the LS1 brake upgrade form bigbrakeupgrade.com. However, as you already know the stock rear disc brakes suck. I was reading a thread stating just rebuilding your factory calipers would cause them to work correctly again. Anyone have experience with doing so? I considered the 4th gen. rear upgrade but i have a factory 9 bolt so that's a no go. I would just assume buy new calipers to do the function versus rebuilding them. The link below is where I read about rebuilding the calipers to work again. Also any advice on some good rear brake pads? I have hawks performance pads going on front! Finally since I am going to have to bleed the whole system anyway would it be wise to install a new master cylinder since the current one installed is the original. Thanks for your time guys!

 

Welcome to TGO.

I replaced the Delco-Moraine calipers with new and never experienced any issues.

So you're choosing the 9-bolt over the fourthgen rear?

Hawks all around.

I wouldn't replace the master if it's still functioning as designed.

JamesC

 

Not sure why you are thinking you can't use a 4th gen rear because you have a 9-bolt?

What you have now matters not the least. If that's what you want, just go ahead and do it.

The Saggy calipers can supposedly be made to work reasonably well, IFF (that's the mathematical "if AND ONLY if") you do 4 things:

• Get newly rebuilt ones (with the parking brake goodies not all frozen together with rust)
• Get the "recall kit" for them from GM, why "rebuilt" ones don't come with it is a mystery to me, but they don't
• Do the combo valve mod, the instructions are on this site somewhere
• Use the parking brake EVERY TIME you get out of the car, NO EXCEPTIONS, and use it twice on Sundays, because that's what keeps them adjusted up. If you fail to use it regularly they will fairly quickly go back to being just ike they are now ... basically, a bunch of unsprung dead weight on the rear.

They'll probably never be "as good as" the PBRs, but they will at least be somewhat functional and less inadequate; and you won't have the problem that you otherwise will now, with those MUCH bigger ones up front, of your brake bias being 100%/0%.

 

I guess I wrote that wrong... I am happy with my 9 bolt, I just want some 4th. gen rear brakes on her. PBR's are what they are referred to as, correct? I was reading a post stating that the factory PBR backing plates won't fit correctly on a 9 bolt. I just want something outback to work versus the stock puppies, which don't.

 

If 9-bolt backing plates are used, 89-97 PBR's (1LE/LT1) can be used without issue. Check the following link for the correct plates:

http://www.flynbye.com/catalog/i31.html

The 9- and 10-bolt thirdgen braking systems, with the exception of the backing plates, are the same, so the following link may provide helpful info:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

JamesC

 

"If 9-bolt backing plates are used, 89-97 PBR's can be used without issue. Check the following link for the correct plates:"That is awesome thanks! Now is that for use with stock 89-97 rotors? or my current rear disc rotors? Will the e brake still function as well?.... I guess I should say will the ebrake actually work now? lol... almost there soon this will stop like a pro!

 

Peruse the second link. Your questions are covered, I think.

JamesC

 

More about parking brake cables and the combination valve:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

So I think I am more confused than before. The back plates are used with stock 11.6 rotors, and they allow the PBR's to be bolted up. However I need to find/buy calipers fully loaded? Meaning the mounting hardware of the rear of the caliper to allow the e-brake to be hooked in? I figured the ebrake cable would have to be changed, and wheel bearings and seals were already a done deal since I had to pull the axles. I already have a disc disc proportioning valve. Should I change that out too? Thanks - Ryan

 

Yes.

The PBR's will require new parking brake cables (whether you purchase loaded calipers or not makes no difference). The parking brake hardware can be purchased in the site I mention above. Here's what you need: http://www.flynbye.com/catalog/i233.html

For best braking performance, you'll need the 1LE combination valve, which can be bought at the site I mention above. Here's what you need: http://www.flynbye.com/catalog/i40.html

JamesC

 

So in searching around for the 9-bolt PBR setup, is it correct that what you need to convert from 10.5 discs to 11.6 discs is:

1) Fly-n-bye backing plates
2) Reman loaded calipers
3) Discs & pads
4) Fly-n-bye parking brake kit

Maybe it would be economical in the long run to just put it together piece by piece instead of buying some crappy used setup and then replacing discs, pads and one seized caliper or something anyways.

Any one source for all these parts? Fly-n-bye has it for $800 at http://www.flynbye.com/catalog/i10.html ; I thought that was pretty steep but maybe not for what's there.

 

If you purchase reman loaded calipers, you won't need pads. You'd also need the correct combination valve.

Since I'm lazy, I'd opt for the kit--everything you need in one shot.

JamesC

 

In 89, the 9-bolts came stock with the PBRs, so you could find a stock set to swap on, or just grab the whole 89+ 9-bolt & put it under your car. Easier to swap & probably only slightly higher cost & you aren't likely to find a set of the 9-bolt PBRs that you can just take off vs a complete rear end. I sold one a few years ago for $200 complete & it was a perfectly functioning rear.

Or to put 98+ rear brakes on, the backing plate only needs the 4 mounting holes modded to fit then they will bolt right up with very little effort. Not sure on the parking brake cable, but I think it needs to be modded to work or buy an aftermarket cable with the correct ends on it.

 

I have an LS1 rear disc setup, all the holes need to be hogged out to line up and a spacer made to seat the bearing properly, then change the e-brake setup. I thought it would be cleaner to just find an LT1 or 1LE set, but perhaps easier said than done.

Might just break down and make up the spacers.

 

lmk how it works alright bb