I got an LS1 rear without the claipers or rotors from a friend. I currently have a set of aluminum PBR calipers and rotors off of a 1LE car. Is it possible for me to bolt the PBR calipers to the LS1's rear backing plates and then put on the PBR rotors and have it work? I have searched around for a while and not found a definitive answer.

 

I have no personal experience with the subject at hand. However, in the following link, Ed Miller, a members whose opinion I value, says that LS1 brakes will fit the 10-bolt backing plate--which means that PBR's will bolt up to it as well.

https://www.thirdgen.org/forums/brak...-ls1-rear.html

JamesC

 

Sounds like it should work. Could I also instead put on the PBR backing plates (instead of leaving on the LS1 plates) on the LS1 rear and then put on the PBR calipers and rotors and be OK?

 

I believe it'll work.

JamesC

 

With the different offsets it might not work. 4th gen rear ends are also wider than 3rd gen rears. I would say take some careful measurements, but you might be better of just picking up some LS1 rear cals and rotors off ebay. Is your 3rd gen a factory 4-wheel disc car? if not you'll need a new prop valve as well. Good luck

 

Won't work. The LS1 calipers are wider than the PBRs you are talking about and the carriers are also different. If you have the LS1 rear with the backing plates installed, just buy the parts you need to finish it out correctly, otherwise you'll have to swap to LT1 backing plates to install the brakes you have, which will work just fine. You can't interchange the LS1/LT1 brake parts.

Ed

 

So the 10-bolt LT1 backing plates will accomodate the PBR set-up?

JamesC

 

Yes, since the f-bodies used the same rear discs (with the exception of a weighted ebrake actuator) from 89-97.

 

Where I was going with the question above was here: If the 10-bolt LT1 backing plate (93-97) will fit the LS1 rear end, then the 10-bolt PBR backing plate (89-92) should fit as well, shouldn't it? If so, then the PBR's will bolt up as Tibo would like. Am I off in my reasoning?

JamesC

 

He seems to think they will bolt up just fine. They won't. Cheapest solution, just get some LT1 backing plates. JamesC, I believe that is what you were trying to get across right? Well then yes, it's as simple as that. Where Tibo was incorrect was in his assumption that the 89-97 PBR setup would bolt right up to the STOCK LS1 rear backing plates. THEY WILL NOT. And in reality, the 98+ brakes are also manufactured by PBR, so calling the LT1 style PBR doesn't make much sense. Just to clarify. Hope this is all making sense to the guy who posted the thread in first place. Get your hands on some LT1 backing plates, and that should be it. Now, if your car is not already 4 wheel disc, you'll need considerably more to do the swap effectively as well as safely.

Will

 

thats what i was gonna say...just get the proper PBR 90-92 backing plates or LT1 backing plates.

or finish it off with LS1 rear brakes which doesnt make sense since u have decent PBR's

 

Thank-you! That clears everything up. I already have the 4 wheel disc, and both styles of backing plates, so this weekend I will have another new project. Seeing as the LS1 rear plates are thicker though, will I have to shim the backing plates I am going to use? Much like the guys going from an LT1 rear end with LS1 brakes have to do?

 

It will not work without some sort of modification. I've got a 2002 rear in my Z28, and attempted to put a disc brake setup on from a 94 rear. The LS1 and LT1 rears are different lengths, and so are the axles. The PBR plate will bolt up to the rear just fine, and so will the bracket and caliper. However, because the LS1 rear is slightly shorter (from flange on tube to end of tube) the rotors will contact the caliper bracket. You can either install a small spacer between the axle hub and the rotor, shim the bracket, or grind the bracket for rotor clearance.

 

I find it very odd to hear this, seeing as I mocked it up without the calipers and it worked out fine. No rubbing or anything.

 

Went through tonight an measured everything. I do not know about overall width, but it seems that the LS1 rear uses a larger spacing between the rotor and the caliper backing plate. It is bigger by .3". so it is possible to use the LS1 rear with the 1le rotors and caliper ir a small spacer (or a few thick washers) are used to even out the spacing on the LS rear. The washers would go best between the backing plates and the rear end's mounting flange. I might try this, as purchasing the LS1 calipers and rotors is a $200 endevour.

 

There's the shim (three on the floor, one placed as you suggest). This is one a thirdgen conversion 82-88 to 89-92, but the idea's the same, I assume.

https://www.thirdgen.org/forums/atta...s-89-shims.jpg

JamesC

 

I am just now getting around to fooling around with the rear end some more. The way that the 9-bolt rear end brake assemblies are set up with the pbr's will not directly bolt in. first I had to redrill the backing plates to fit the axle housing. Then I noticed that there was not enough clearence between the backing plate and the rotor so that the caliper could bolt between them. So next I am going to try to put the caliper on the other side of the backing plate as suggested in the picture that was posted earlier. I may not have to use a shim though.

 

Did some more work and found out that the PBR brakes will not fit on the LS1 rear end with out major modification to the backing plates. Either way that you stack the backing plates with the rotors. there will be an interference or not enough/too much room. It is doable to put the LS1 brakes on a 10 bolt rear end, but not a 9 bolt.

Some of this info on rear ends should be put in a sticky or tech article to avoid more of this confusion. As it will cause more confusion.