Fox Brake pedal too stiff

[keel]

I was doing some spirited driving over the weekend and realized that in order to get full braking power I need to put way too much effort into the pedal. To be clear, I don't think there is anything mechanically compromised with the braking system, just something wrong with the way I set it up.

I'm running SN95 Cobra brakes on all four corners, gutted OEM proportioning valve and a Wilwood adjustable to manage brake bias, and a 1993 Cobra master cylinder with a Fox V8 booster. I've done some research and it seems like a '93 Cobra booster is what I need to get the pedal feel I'm after, but I also wonder if I need to go to a different master cylinder too. Looking for some opinions for this combo and how to proceed so I can get it right without messing around too much.

 

[AeroCoupe]

Cobra MC is the preferred MC with the 94-04 cobra brakes on our cars.

Several folks have run the Fox booster with success so I would not just say they don’t work. Most run the 1993 Cobra booster as the studs on it fit the existing g firewall holes and it does provide more boost than the Fox unit can.

Based on my experience I would run the 1993 MC and booster. Stick with known brands of boosters.

 

[Mustang5L5]

Which generation Cobra brakes do you have up front?

If you have the 94-98 versions, you'd really want the 94-95 Cobra 15/16" MC. (they can be used with the 1" 93 cobra MC but first stop on cold pads might be a little lacking)

If you have the 99-04 versions, the 93 Cobra 1" MC is the right one.

1993 Cobra booster should be run with both.

Easy way to tell is to cut the wheel and look behind at the piston bores. 94-98 are ribbed, 99-04 are smooth

 

[keel]

I'll have to take a look. What's the difference between them internally?