I just picked up a 9 bolt rear for my 91 rs. It has rear disk opposed to the factory drum brakes. First off will my proportioning valve need to be changed or did the disks and drums used the same valve. Second, I am not sure what year the 9 bolt came off of; do all third gen rear disk use the same pads or do they vary by year? Thanks Guys

 

pads depend on what brakes are on it. if they are iron caliper, they suck, aluminum calipers are the best ones. they both use different pads, and the change was in 88 or 89 IIRC.

your prop valve will "work" but a proper disc/disc valve will be better.

 

I have Iron calipers on the back. So i would be safe with any pre 88 rear brake pads? Just want make sure I order the right stuff.

 

yeah, they are the same

 

What makes the iron ones suck?

 

they are notorious for not working, at all. search, there are many threads trying to "fix" the problems.

 

The old Delco-Moraine calipers (82-88) certainly have a bad reputation on TGO, though from my own experience, I'm uncertain that it's entirely merited. With new calipers (or old ones with the "fix" kit in place) and frequent use of the parking brake, I personally had no issues.

As 86 mentions, the new style system with PBR's (89-92) is the better choice. These can be swapped to your 9-bolt.

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

You may also find info in the following to be of interest where combination valves, master cylinders, and parking brake cables are concerned:

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

JamesC