Brake Issue after Installing SN95 conversion

[Blown331LX]

I have a 1990 GT that I've been building for the past 2 years and finally got it driving a few days ago. First I'll give specs on car then describe the problem and ask for help and advice. Car currently has SN95 spindles and balljoints, dual piston PBR calipers, cross drilled rotors and the steel braided lines from Maximum Motorsports for the conversion from stock hard lines to the PBR calipers. The rear is the stock brake drum setup with the exception of the Moser 5 lug axles. No the problem is that the brakes dont feel great and dont stop on a dime like I thought they would. It almost feels like the pedal isn't as firm as it should be or as if the rears are doing most of the work. I have not swapped the master cylinder or proportioning valve cause I didnt think it was needed. All the lines have been bled multiple times and are free of air and the rear brakes are in good adjustment. Im really lost as to what to even look for. It doesnt feel like a bad master cylinder but it just doesnt feel like performance brakes but more like the factory brakes on my 1977 F150 lifted 4x4, to give a comparison. All input is welcome..........

 

[GSP393]

Contact Richard at North Race Cars. He is a genious when it comes to brakes, esp. fox 5 lug swaps.

http://www.northracecars.com/index.html

 

[bullitstang1313]

I'm not a genious when it comes to this stuff, but my guess is that you need to swap the master cylinder and the brake booster. The stock booster was designed for such small brakes and now that you have the 2 piston calipers it might not be able to give you the necessary help. I imagine the master cylinder needs to be swapped out as well. I'm not sure about the proportioning valve but I imagine that since the fronts are dual piston calipers and the rears are drums you probably need to adjust it as well.

 

[ttop88]

I vote master as well. Since you still have rear drums you don't need a differant prop valve. I used the master off a 88 lincoln lsc.