I saw a Rx7 down at the yard and it had rear disc brakes on it. I want rear disc but am wondering if I should just pull the whole rear end or just take the brake parts.

I will need to pull the Master cylinder and the power booster too correct?

Can I use my existing brake lines or am I gonna have to pull the ones from the donor?

 

Take the whole rear, the e-brake cable(at least from where it splits back), you should be fine using your master cyclinder, but if you can get it for not much more why not take it as well, yes you could use your stock lines. Good find.

 

The master cylinder itself should be fine to use but I would grab the proportioning valve. You might want to take the rubber hose part of the brake line that goes from the chassi to the rear end. I had problems getting mine disconnected when I did the swap and found it easier to just use the line off the donnor car leaving it attached to the axle housing.

 

I didnt swap anything in the front and mine works 100%

 

The thread pitch on the brake lines is different between SA's and FB's. I believe MazdaTrix sells a set of lines with the different threads on either end to make the swap easier.

 

check this link out:

http://www.mazspeed.com/axel.htm

I swapped an '81 axle into my '79 GS and all I did was take one of the ends off of the hard lines on the old axle and make new lines for the '81 axle, incorporating that end so that I could just plug and play.