Would it be easier just to swap the whole rear (the gears are the same size), swap the discs? Are theh calipers different? I assume they are.

What about the master cylinder? Brake booster? Should those be swapped? Or are they the same?

 

No such thing?

If you have cast-iron calipers now, they were made by GM's Saginaw plant, not purchased by GM from PBR in Australia.

Yes the calipers are different. Totally. So are the rotors, backing plates, and every other bolt-on piece.

You can easily swap the entire PBR system onto an earlier Saginaw disc rear without modifying the rear. You need the backing plates, calipers, caliper carriers, rotors, hydraulic lines (the ones on the rear itself including the rubber hoses which are different), parking brake cables, master cyl, and combo valve. Direct swap. Booster AFAIK is the same.

 

Your right, my bad. I have a 9 bolt under my 87 and 89, both with 3.27 posi gears, so I wanted the larger brakes. I think it'll be easier to swap rears, than changing the parts out.

I was just curious if a simple rotor and caliper swap would suffice.

 

The following link details the procedure:

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

JamesC

 

Thanks.

I'll be doing the complete rear swap them. Much easier than messing with the backing plates, etc.

 

Hey, not to hijack your thread but I'm also stuck with the cast iron junkers. I've got a 88 IROC and I'm looking to do something with the rear brakes. I've also got the 3.27 rear end. You are just going to pull the rear out of your 89 and bolt it in to your 87?

I'd like to know how it goes cause I was going to do the LS1 swap, but if all I need to do is find a donor 3rd gen from 89+ that's prob easier if it's just swapping the rear.

 

The section of country you're living in may make a difference, but in my years of junk yarding, I've only come across two 89+ cars that had PBR's. Maybe just bad luck.

JamesC

 

If the car doesn't have PBR's what does it have then? Are the rear disks on a 89 IROC different than my 88 IROC?

 

For even bigger brakes, get a 4th gen rear. 93+. The 4th gen rears are a direct bolt in, and 2" wider. The 3rd gen rear wheels still fit, even with the backspacing & such. They are pushed out to the edge, but still fit good.

 

Drums. Yes. Your 88 will have iron calipers and 10.5 inch rotors; the 89-97 will have PBR's and 11.7 inch rotors. Check the link I provide above for pics.

JamesC

 

So if I got the entire rear end out of a 4th gen, it's a direct bolt in... Cept the E-Brake cable of course.

Is it really that simple?

 

I'm not 100% certain on the threads of the brake fitting, nor the ebrake connections, but the panhard, control arms, driveshaft, torque arm, and shocks, are a direct bolt in.

 

I know you need to rig up a little adapter for the E-Brake. That's not so bad, but just wondering if the driveshaft, and everything that is important bolts up. Cause if it's as easy as just jacking it up, pulling the old one and putting on the new one... I'm def down for that

 

Didn't I just post, that those were direct bolt ins? I try to get ahold of the guy I know, and see what he says about the other stuff.