n00b brake question???

[Tonys96Cobra]

My 89 Gt has the T-bird turbo coupe rear disc brakes, but I think the master cylinder is bad. So do I use a Mustang mc or a T-bird mc? I also noticed it has a proportioning valve mounted to the pass side firewall, how do I know where to set this??

 

[srothfuss]

When most people switch to the 4 lug set up they run either:
1) 86 SVO Master cylinder
2) Cobra Master cylinder

There are a few other choices out there, but this site does a better job of explaining it than I can. http://www.svo73mm.cjb.net/