i have an 87 formula with stock drum rear brakes. I want to convert it to disc. Aside from the disc brake hardware (backing plate, rotor, caliper, etc) is there anything i need to change (such as axles which i plan to upgrade from stock anyway)

axle brake lines and parking brake cables. the disc backing plates will not just bolt on the drum axle you will need to do some modification. look in the tech section there is an article on how to convert to ls1 rear brakes, and can usually find the setup on ebay for under 200.. they are much better and the conversion is not that bad. you just need to get custom e-brake cables and edmiller is working on that now.

thanks, that's about what i thought, i need new parking brake cables anyway, and was planning on using different axles. As for break lines, that's easy. sounds like it will be pretty simple.

not to confuse you or get some things misunderstood here. by axle i dont mean axle shafts. so long as you have a 10 bolt the shafts are the same, drum/disc except 26 and 28 spline. the axle housing ends are what need to me modified.

i realize that, but i plan to beef up the whole rear end anyway, plus everything else has broken on my car except that so far, why not replace before it breaks too

THIS IS NOT TRUE!

when a fellow cascadecrew member Twilightoptics twisted an axle shaft in his 10 bolt with 82-87 disc brakes i gave him one of the axles out of my 2.73:1 drum 10bolt and he had to have the axle flange turned down to fit the rotor hat over it. we actually had to do this twice. he broke that same axle the next time he launched the car .

i've PMed him, perhaps he can give you a bit more info on the whole thing.

more info would be great, cuz now i'm suddenly confused, maybe just cuz it's 4:30 in the morning and i'm trying not to fall asleep in class, or maybe i'm just a dumbass, i don't know which.

I do not have the experiance with 28 spline axles... they may be same drum vs disc but in the case of 26 spline axles:

THEY ARE NOT INTERCHANGEABLE! To a point. The drum brake axle flange is too big to fit in the disc brake rotor. You can have a machine shop turn the drum brake axle flange down on a lathe to fit inside the rotor.

I've done this twice since I've broken two disc brake axles at the drag strip and the only axles available at the local bone yards were drum axles.

I suppose you could use disc brake axles in drum though, but I would be cautious. The flange is bigger on the drum brake because it fits snuggly in the drum itself keeping it centered and in balance. Same for disc.


Just the FYI.

Ciao
-P

84 Camaro, 87 trans am rearend w/discbrakes and posi, what else do I need? master cylinder, E-brake cable, propotioning valve, torque arm

why isnt there a tech write up about this conversion? there certainly is enough ppl doing this or wanting to do this

on discs the hub of the axle is what keeps it centered. i dont think the flange has to be that precise, the hub and lugs should keep the rotor well centered. but the 26 spline axles are different btw drum and disc rears. my axles are at the machine shop now because my discs wouldnt fit over the flanges.

oh well thats why its called car crafting and not car assembling.....

The axles are indeed different and depending on which rotor you use, turning of the flanges is not required.

I have plates for the swap and you'd need the brake parts, which I also have.

https://www.thirdgen.org/forums/brak...ghlight=plates

I'll try to post up pics of the other rotor tomorrow.

Ed