Well i just finished my drum to disc swap on my 10bolt that i put in my 'roc and theres a few things i thought i might comment on for those looking to put some discs on their drum rears...
(These are things i ran into that were NOT mentioned elsewhere...)

1. 28 spline axles are NOT interchangeable from drums to discs. They can be made to work just fine but the flanges are a little bit to big in diameter for the rotors to fit over. Not a big problem, just take them to a machine shop and have them turn the axles on a lathe. Its only about 1/8'' of material that needs to be removed. Axles are made of very tough steel (obviously ) and the flanges are pretty beefy. This isnt something that can be done easily with a dremel or cutting wheel. My machine shop only charged me $40 to do this.

2. There is no need to cut the tops off of the brackets that the backing plates mount on to. The backing plates fit just fine. Just make sure you use really high quality drill bits and drill a pilot hole first. The brackets are about 1/4'' thick and cheap drill bits just get dull without really accomplishing anything. This is probably the worst part about the whole swap in my opinion. It took forever to drill those damn holes even with carbide bits!!!


3. If you are planning on using stock calipers and rotors as i did, they are OFFSET!!! The passenger side caliper mounts on the front of the rotor(towards the front of the car), the drivers side caliper mounts on the rear of the rotor(towards the rear of the car). This should be obvious if you pull your own parts at the junkyard but i did not and i mounted both of my calipers on the rear of the rotors. Then i realized that one bleeder screw was on the bottom of the caliper . I managed to bleed it by taking the brake line off an on but it wasnt fun and it made a mess. It really doesnt matter how you mount your calipers except bleeding the system will be MUCH easier if you have both bleeder screws on the top of the calipers.

4. 9 bolt and 10 bolt rears are completely interchangeable. There is nothing you need to modify to put a 10 bolt rear into a 9 bolt car or vice versa.

Thats all i can think of right now. I hope this helps. I am MUCH happier now that i ditched my 9 bolt with 2.77s in favor of a 3.73 10 bolt disc. Now to finish my t-56 swap!!!

 

did you do the ls1 rear brake setup? or use thirdgen stock rear discs? both calipers should be on the same side of the rotor, one does not mount on the rear and the other on the front , if this was the case on the doner car, something was a little fishy with it.

 

Couple questions.

Like asked above, Did you do Ls1 or third gen rear disk?

And You are saying you dont have to cut the top of the brackets off, Just drill holes??

Question 2 will be answered if you used ls1 or third rear setup.

 

no i just used stock thirdgen parts. when i pulled my 9 bolt off of my car i realized that the calipers were offset. my car came with 4wheel discs and the 10 bolt i built for it was a drum rear. so i built the 10 bolt and put discs on it before i ever touched the 9 bolt. i dont think it really matters but it was a little odd.

88vert- no you do not have to cut the tops of the brackets off, at least i didnt have to. the backing plates do not interfere with them and like i say, those brackets are pretty beefy, it wont be fun to cut them. i just didnt see the point in wasting all that elbow grease...

 

well, the tech article in question refers to the ls1 rear swap, which is a totally different animal than the thirdgen rear discs. the axles, for disc and drum have different size flanges, which does not matter with the ls1's because the brakes are bigger, so either will fit inside. the backplates for the ls1 brakes are also different, due to an internal parking break, so you have to cut the axle flange, unless you use edmillers new adapter plates. the stock third gen plates are much bigger, so i can see them working without cutting the flange