I am getting my hands on an 88 9 bolt with disk brakes that I am going to put on my 89 RS and I have a few questions if anyone can help me out.

1. The guy that I am buying it from removes the brake lines (but the rest of the brakes are there). What will I need for line sizes and fitting sizes? How about the box that joins the two lines to the hose?

2. The 89 RS came with drums in the rear, do I need to replace the master cylinder? I know that I will need to get the a proportining valve, would a stock valve be better that an adjustable?

3. PBR brakes seem to be all the rage, what are PBR brakes? (I realize that they are better, however, the 88 disks must still be better than the drums... and I need the traction from the posi, my mainly stock LO3 just can't grab with the stock rearend... spins the right wheel through first and into second.)

I know I will have more questions later, but this should get me started.

Thanks for the help...

 

I'm doing the same thing with my 90 Formula. I picked up an 88 9 bolt with discs and also got the complete master cylinder in the deal. I'm just wondering if I really need to swap out the entire master cylinder/booster or just swap the prop valve. I also have to get new hard lines as well as park brake cables.