I just bought a rear end off of a guy and he wasn't real sure what year it is. May upgrade the brakes anyway but I'm trying to figure out exactly what I have. It has PBR calipers, rotors are 12"x ~.75 (worn quite a bit), and someone has changed to an aftermarket posi and 4.10s. these cars only got the zexel torsion posi from the factory, right? the pinion gear and posi carrier have some damage...looks like someone didn't tighten the pinion (yoke) properly and the pinion gear pulled back into the posi carrier. may still be usable but I don't plan to use them, don't want the 4.10s in my car. thanks for helping me ID this stuff!

 

LS1 brakes have a little drum setup inside the rotor, for the parking brake.

The LT1 setup looks just like the 3rd gen PBRs.

What happened to that rear, is why I prefer to use a solid spacer aka "crush sleeve eliminator". It DOES NOT come from "not properly tightening" the yoke nut; it comes from the fact that you only can tighten the nut until proper bearing preload is achieved, and the only thing holding the nut from backing off (except the Nyloc, which is mostly insignificant) is the degree of crush on the sleeve. The spacer on the other hand allow you to put as much torque as you want on the nut.

 

Alright so I guess I got lt1 rears because there's no drum I nside the rotor. Are they as bad as some people say the are? Are the rotors the same diameter between ls1 and lt1?

 

As said, the LT1 setup is for all practical purposes identical to the 89-92 setup; just on a wider rear.

Nothing "bad" that I know of about them, as long as you can manage the parking brake actuation program. Speaking strictly as someone who owns a 89-92 setup installed on a 83 car.