I've been searching and searching this brake board to understand how to upgrade and/or repair the 88 IROC rear disc brake failure issue. I just got my 5.7 1988 IROC and the rear brakes are shot.

I've read several posts where it says that there's a repair kit, but it's better to switch to the 89 and up rear disc set-up. BUT; I CAN NOT find a post anywhere that shares what this involves, what parts are needed, and if this really is a much better fix than just doing the repair kit?

Isn't there a link that covers this issue??? Nitro (the frustrated!)

 

There have been several threads over the years, as well as a link or two in the tech articles. Essentially, you replace everything from the backing plates out with the corresponding parts from the later setup.

 

THIS IS THE POST YOU ARE LOOKING FOR!!!

tons of info, and alot of good pictures. just did this swpa TODAY. 88 GTA w/factory disc. put a 3.23 9bolt w/disc of unknown fbody origin into it. added the lter model (sometimes reffered to as "1LE brakes") on it. half way through i hit a snafu and found this trhead. now it's solved (turns out the "right" backing plate needs to go on the "right" side of the car . but they were mislabled, so it's a mistake anyone could make. )

anyway here is the link 82-88 Discs to 89-92/Pics and Part Numbers

 

do have a 10 bolt or a 9 bolt rear end?
the 10 bolt backing plates are $15 each through GM.the 9 bolt backing plates have been discontinued.i can supply these if you need the 9 bolt backing plates.

 

I havn't done an actual visual on the rear, but the code is: GH3, 2.77 Ratio / G80, Axle, posi-traction, limited slip.

I didn't know yet that it mattered for the brakes, but I' are sure learnin fast!
Nitro

 

I feel like such a goof ball! I've worked on my cars for years, but just have never had to identify and do this type of stuff before.

I jacked up the back end and counted 9 bolts on the rear cover: 3 on the bottom & 2 on the other three sides. It has the tab for the 2.77 gears (which compares to; I don't know what yet on these IROC's) and has the G80 limited-slip build code.

I'm assuming, since the rear brakes are mush and not working right, that it probably has those bad calipers.

I'm going in for spine surger tomorow morning and just havn't been able to bend down and check all this stuff yet. It's just a hoot to drive!!!

The system has approx. 150k miles and the brake fluid was dark and lightly gritty. Unlike some high mileage systems, there wasn't a bunch of sedimint on the bottom of the Master Cylinder.

The guy I bought it off of got drunker and drunker as the deal went along (he was pissed to having to need to sell/original owner). I has asked him about the brakes midway through the first case of beer for the day and he mumbled that he had turned the front rotors and replaced front bearings, but 'screwed up' on the rears. After that I just wanted to get the hell away from his breath.....
Wow, what fun!!!
Nitro