Front Brake Selection Help! 1970 Trans AM

[Ron Sutton]

Wilwood's site is not acting good tonight for me to check out some of the stuff..Seems liek half the time their site doesn't work well for me.

I guess we need clarification which D154 calipers you have on the rear they make a single piston,larger dual piston as well as smaller dual pistons. Factory iron D154s use a 2.5" piston as did the 79-81 TA 4 wheel disc setup. I think if you have the smaller 1.12 dual piston caliper front selection will not be as tough to balance out. Heck even using their dual piston D52 caliper on a 12" 1LE/B body rotor would probably be close to the factory F body system for balance.

Ron plug the 2.5 rear single piston caliper in with a 11 3/16" rotor 1" for a factory F body rear disc setup as a comparison also besides the disc/drum.

Also most factory power brake systems disc/drum or the 79-81 disc/disc used a 1 1/8" MC, the '81 was quick take up aluminum.Manual systems did get a 1".

Ratio is probably around 5:1 I know moving the rod up for a manual gets right around 6:1. 79-81 TA 4WD used a ratio even lower than 5:1 as they used a more assist dual diaphragm booster. Booster selection makes big difference ion the system also.

Hey Skip,

Thanks for chiming in. JT hasn't purchased a master cylinder yet, so he doesn't have a stock 1-1/8" version. I am recommending a 1" M/C to provide more overall braking force. Of course, when we compare different brake set-ups ... and we keep the M/C & pedal ratio size constant ... it shows us the true braking force differences in the caliper/rotor/pad combo ... and that difference percentage doesn't change with master cylinder size.

I worked up the examples you suggested. I put 1-1/8" M/C across the board. The first one is the 1970 set-up with drum brakes & 11" rotors. The second one is a 1980 TA with disc brake rears & the larger 11-7/8" front rotors.

The third one shows trying to use the small piston Wilwood rear calipers that JT currently has. You can look at the numbers & see they just don't produce enough braking force for a good hot rod, let alone a road course track car. The fourth set shows option #1 from the list above ... but with a 1-1/8" M/C.