85 Mazda Rx-7

Hey guys, what would be the best way to go about upgrading from rear drum brakes to rear disk brakes? I have an 85 GS so I am wondering if I should, and how to go about it.

Felix Wankel

Easiest way is to find an 84-85 GSL parts car and swap rearends out.

Project84

yeah, take the axles and all. Just don't forget the e-brake cables.

MATRIX XRS

You aslo have to do the brake lines. I had an 85 gs and because I did not feel like switching everything, I put the 4.08 limited slip from a gsl-se in. It actually made a noticeable difference in acceleration. Everything else is completely stock(except K&N) and I was able to hold an 88 gxl by 3 cars till we both shut down at 95mph. I would not worry about rear disk that much. The brakes on my car worked great. It autocrossed fine and every thing.

Kill No Cone

iTrader: (6)

Don't forget the master cylinder as well. The GSL (with the disk brakes) has a different proportioning valve. So, if you forget the master cylinder your brake bias (front to back) will be off.

gonzz

Can you just install a LSD pumpkin? Or do you have to swap the rear end to get LSD ?

peejay

You can swap just the pumpkin. To make things easier keep the swap in these year ranges: 79-82, 83, and 84-85. You can swap 83 with 79-82 if you also change the driveshaft flange and/or use the same year driveshaft.

Kill No Cone

iTrader: (6)

Well, the easiest was is to swap the whole rear end. If you have an 85 you will want and 84 or 85. And, I think that you would want the dick brakes as well.

Kill No Cone

iTrader: (6)

Ok, so I ment disc brakes; but if you do it wrong you could dick'em too.

V8kilr

check out my write up on gsl-se suspension swap

click me


i finally have it hosted on my site and its better then ever

Felix Wankel

You really should tell people not to tighten any of the link bolts up until they've set the car on the ground.

V8kilr

because all but one of the links are removed from the rear end itself they keep there position,
you will have the use a floor jack to ge the rear end into place anyway

it was just a quick write up
i did it mainly for the pictures since people have walked through it before but no pictures to really see what was involved

twister

Another choice is to go for a full floating hub set-up, and manufacture a mount for your brakes onto that. I use this set-up in my racecar with great success. You then get fantatsic after market axles, the entire set-up is much lighted, the advantage of easy changing of diff centres and remove the problem of axles causing seal leakage dramas etc. Let me know if you want details of where I got them in OZ, Cheers.

jeremy

iTrader: (1)

hey dave, where's the dr pop portion of the write up?

V8kilr

I figured the sponser link was enough,

I have attemted to contact them in hopes for real sponsership but so far no luck

I have about 6 empty 12 packs here already

jeremy

iTrader: (1)

haha, thats awesome. i need to get more. i'm going through detoxification right now