I am looking for rear brakes for the 9 bolt rear end im getting soon. I have backing plates for the 88and older steel calipers and a set of heavy duty backing plates for 89 and newer Alum calipers. Now i just need brakes on this thing so my car will stop. Can i put ones from a 10 bolt on or do they have to be off of a 9 bolt? what are all my options (years, alum vs steel, etc) and what is the best choice.

-chuck

 

NO MATTER which calipers/brakes you go with.You WILL need the backing plates for a 9 bolt.There 4 types in all.Two for cast iron calipers,one for 10 bolts & one for 9 bolts.Plus 2 for the aluminum calipers,also one for 9 & one for 10 bolt diffs.If both your backing plates are from a 9 bolt diff.You can use any 82-88 cast iron(not steel)caliper or any 89-92 aluminum caliper brakes.Its the backing plates that are different in the bolt pattern where it mounts to the diff.The rest of the backing plate is the same.Just make sure you use the correct backing plate for the calipers.The PBR(alum) are the better brakes though.

 

i would go with the 89+ setup. i'm in the process of doing the conversion myself. i have a rear from an 85 TA, 9 bolt 3.27 posi disc. i bought the plates and cradles from a member of this site and ran to napa and got 2 loaded calipers, discs and e brake cables. i'm just waiting for the new hard lines to come then i will stuff it in the car. i wouldn't waste the time or money with the pre 89 discs just because they don't work as well and they cost more in parts. my suggestion is use your 89+ plates, buy some cradles and get the calipers and discs new from NAPA or another parts store in your area.

as for the mix of 10 bolt and 9 bolt brake parts, i have no idea. i would think they would be different, but i'm not sure.

 

OK, so I should go with the 89 and newer aluminum calipers and matching rotors.

How new can i go? do i have to stick to the third gens or can i get ones off of the forth gens. And what is a cradle?

-chuck

 

you can do any setup from 89-97. i suggest staying with the 89-92 years, the newer ones are the same except for the crown on the caliper. no preformance difference. i went with 92 parts on my 86.

the cradle is the actualy piece that holds the caliper to the backing plate. ebmiller88 has all the parts you need to complete the swap. i got all my parts from him and was very pleased with them and the time it took to ship. i suggest talking to him for cradles.

for calipers and rotors, i'd just buy them new and loaded so you don't have to go on a hunt for parts or worry about the abuse they took from the previous owner.

 

If you have a set of the 89-92 ten bolt pbr plates, you can easily modify them to work on a nine bolt. All you have to do is router the holes slightly where they mount to the axle housing flange. A friend of mine just put a nine bolt in his car in place of the pbr ten bolt, and we swapped the brakes over just fine doing this. All we did was use some spray paint on the backside of the plates, then held them up to the axle flange, made sure the angle of the plate was right for the caliper to be in the correct clocking position, then scribed marks in the paint on the brackets for how much to router the holes. Worked like a charm!

 

Here are the two backing plates, the new is the 10-bolt.

JamesC

 

Good picture James. That's about exactly how much we had to router the holes to make them work. I just put them in a bench vise and used a big drill bit pushing sideways on it, and it went pretty quick elongating the holes.

 

just had to elongate the 4 outter holes not the inside ones right?
does that make it weaker at all?

 

I only elongated the bolt holes in the bracket itself, which shouldn't affect the strength much, if any at all. I didn't do anything the holes in the axle flange itself. I figured it's much safer to fool around with the brackets themselves. Besides, there's not enough surrounding material on the axle flange to elongate the holes anyway. The big hole in the center of the bracket fits the same on either a nine bolt or ten bolt, so no modification is necessary to that part either.

 

thats what i was wondering.

 

Are you certain there is no difference between the 89-92 calipers and the 93-97 calipers? I see that ours have a built in ebrake bracket attached that compresses the calipers. Now on LT1 cars, they utilize a drum-in-rotor ebrake system correct? Therefore the calipers do not have the brackets. I believe the LT1 calipers cost a bit less due to the lack of the ebrake assembly.

The cheapest I have been able to find them is around 95 a piece plus a 50 dollar core, at my dealer cost. Something like 150 w/o the discount, most other places were telling me something like 150 plus an 80 dollar core per side. I'm in the process of replacing my 89 rear with an 87 rear but maintaining the 89 brakes. Getting all new parts because mine are aged and I don't trust em. Plus now I can powdercoat my new rear/suspension/ and brakes on all 4 corners

Will

 

Your thinking about the LS1 models Rr brakes.