If you already have the SN95 stuff done to your fox (SN95 axles & spindles, SN95 booster, MC, proportioning valve mods, etc…), the hardest part for the Cobra upgrade is finding the parts. For the front you need to notch your SN95 spindles (if not already done) and find the Cobra/Mach1 calipers, rotors/pads. The rear you’ll need the axle plates from a Mach1/Cobra, anti-moan brackets, caliper brackets and rotors/pads. Not to mention oil and a helper for bleeding the system.


The Fronts

The front upgrade is pretty easy, I already had the ’03 PBR dual piston calipers so my spindles were already notched and I have the Maximum Motorsports braided lines (MMBK8F) which included banjo bolts that fit the PBR calipers. It was just a matter of removing the calipers/rotors/pads and putting the new ones in. Albeit, I ignored the “L” and “R” stamping and had put the bleeders facing down by accident.


The Rear

The rear involves taking the axles out (yay). I’m not a fan of the brackets you can buy to add to the existing axle plates. So I used the Mach1/Cobra plates, below is the stock SN95 plate with axles out.


Ran into an issue in the back!

So I haven’t read about any issues like this where the caliper bracket rubs on the rotor after the swap (was fine with ’95 brakes). Make sure that your plates are installed correctly, axle housings are cleaned up and it’s all torqued down properly in a “X” pattern. I had to grind down the driver side caliper bracket to increase the clearance a little, passenger side was good.

Can’t find the right anti-moan brackets!?

For some reason these brackets are much harder to find than the axle end plates (or whatever you call it). One trick is to modify the SN95 anti-moan brackets. First cut the bracket as seen below. I also had to remove the lip on one side (not shown).


Spot welded the bracket quickly in place.


Once fitting nicely, I welded it up. There’s enough material to fit the shape of the axle housing and now the bracket reaches the new caliper bracket bolts.


Master Cylinder Sizes

You’re going to want to match the master cylinder bore size with the calipers you’re using. Too small and the pedal will be hard and won’t give you much confidence… too big and you get a very spongy pedal feel. Below are the caliper sizes and MC bore sizes so you can determine what ratios you should have.

Caliper sizes:

  • 87-93 Front calipers – single 60mm
  • 94/95 Front calipers- single 66mm
  • 94-98 Cobra PBR Front calipers – dual 38×38mm
  • 99+ Cobra PBR Front calipers – dual 40x40mm
  • 99+ GT PBR Front calipers – dual 44.5×44.5mm (that or 40mm, need to figure this out).
  • Cobra and 94+ rear calipers are all 38mm

Master Cylinder Bore sizes:

  • 79-86 V8 Mustang – 22.22mm (7/8″)
  • 84-86 SVO/Lincoln – 28.57mm (1 1/8″)
  • 87-93 V8 Mustang – 22.22mm (7/8″)
  • 93 Cobra – 25.54mm (1″)
  • 94+ GT –  23.81mm (15/16″)
  • 94+ Cobra – 26.98mm (1 1/16″)
  • 03 Mach1/Cobra – 25.54mm (1″)


Swapping to bigger brakes isn’t that big of a job once you already have the SN95 5-lug setup. But to be honest, I doubt this will do anything more than look better to me. At least because I don’t race this thing and it’s a pretty light notch to start with. I admit the PBR calipers up front worked extremely well last season. I was real happy with its performance.