How do I convert rear drums to disc brakes?

rusty · Post by **rusty** » May 15th, 2005, 6:48 pm

I have a 93 MX3 that I want to convert my stock rear drum brakes to disc brakes. What do I need to convert everything? Also does anyone offer an aftermarket performance calipers for the front and rear?

fry_81 · Post by **fry_81** » May 15th, 2005, 6:56 pm

it would be best if you got a hold of a GS model donor car and just swap the rear brake systems(i know this is a little oversimplified as i havnt done this before)
as for aftermarket brakes, there is big brake kits out there, but they are very pricey.

Mr_Shorty · Post by **Mr_Shorty** » May 16th, 2005, 2:47 am

I've already bought my doner car for my RS and it doesn't look as easy as just swapping the rear braking system. It looks to me and my friends that you have to take the master cylinder as well as it's much bigger on the GS. Also, you need the rear wheel hubs as well, as they are different on both cars. While I'm at it, I'm just gonna take the whole rear suspension as well to save myself any problems.(I also want the rear tie-link from the GS)

rusty · Post by **rusty** » May 16th, 2005, 1:55 pm

Is the GS a MX3 or a 323? Also it doesn't make sense to me that you would have to change the master cylinder. Even if they are different the original RS master cylinder should still work with rear disc brakes. Will the GS hubs bolt right in to my RS strut mounts? and what years of donor car should I look for?

fry_81 · Post by **fry_81** » May 16th, 2005, 2:55 pm

GS is an mx3 yes. it is the version that came with the v6 powerplant.

rusty · Post by **rusty** » October 28th, 2005, 11:02 pm

Ok, so i finished converting my drum brakes to disc brakes so for anyone interested, All you need to do is get the rear hubs, parking brake cables, flex brake hoses, calipers, pads, rotors. I used the stock master cylinder and works just fine. There is no need for a donor car or the whole rear suspension system to do this job.

jaydog5678 · Post by **jaydog5678** » October 29th, 2005, 2:21 pm

Upgrading to the GS's 15/16 master cyl would be a better choice imo.

I have taken the booster, master cyl, calipers with e-brake cables, spindles, proportioning valve, front brake lines and the lines to the master cyl to the p. valve. That should be everything you need to convert drums to rear discs from the GS brakes.

The rear brake lines that run under the car for the GS looks to be in the same location as an RS model. The GS proportioning valve even has the rear lines exiting in the same location as the 4cyl. RS.

bmwm3guy · Post by **bmwm3guy** » October 29th, 2005, 3:15 pm

I have a GS that I am parting out for those interested in doing this swap.

2fazed · Post by **2fazed** » October 29th, 2005, 11:21 pm

I grabbed all my parts from a 92 Protege. Spindles, calipers, ebrake lines, pads. I didn't replace the master cylinder, or any of the brake lines. The brake lines disconnect just pass the strut, so changing the drum line to disc line is easy. I think most Mazdas from 89-93 (323,626, Proteges) will work.