Stanley
1st Gear Poster
NOTE: This was originally a "help me" thread. However, I've since edited this opening post to reflect everything I've learned and changed it into a guide for others, so the immediate posts by others following it are answering questions or commenting on parts I've since cut from here to minimize confusing / contradictory information. The parts listed are now accurate.
Between how popular this mod is, and the fact that there's multiple valid ways to do it, there's about a hundred threads for this. But the problem is there's about a hundred threads for this: there doesn't seem to be one that is a one-stop shop, and some of them are quite old in terms of part options, or have info that another won't have, or have info that's unclear or apparently contradictory (often because of the fact that there's multiple ways to do this).
This particular thread is assuming that you:
1) want to swap your stock wheel hubs with Mustang hubs, rather than just drill the stock ones out
2) have large (17"+) wheels to go on those hubs when you're done
3) want to upgrade your brakes as well as your hubs
Key Article:
MN-12 to SN-95 Bolt Circle Change
Refer to this article for the step-by-step process. As it's so useful, in case the page ever gets deleted I've converted it to PDF and attached it to this post (see bottom).
Special Note: 89-92 Birds vs 93-97 Birds
For owners with Birds from 89-92, you must first upgrade to T-bird spindles from 1993 or later. The older spindles are different and don't work with these procedures. See this short thread for spindle upgrade information.
Generic Tools / Parts
The biggest hurdle here is the need for a hydraulic press for the rear hubs: that bit isn't something you can just do on your own. The rear hubs are pressed into the rear wheel bearings, which are pressed into the knuckles. However, you can take the two sets of rear hub/bearing/knuckle combos to a shop to have this done: you don't need the car present to get the pressing done.
20 lug nuts (1/2"-20 size).
8 Allen head cap screws (M12-1.75 x 30mm) and 8 M12 x 1.75 hex nuts.
250 ft-lb torque wrench.
2 Wheel bearing retaining rings (OEM Ford N803955-S or Dorman 933-954). The article mentions these, but doesn't tell you what to do with them. These are for the rear, at the knuckle; the fronts don't use them.
4 Retainers.
Also known as Axle Nut, Spindle Nuts, Retainer Nut, Hub Assembly Retainer Nut, Hub Nut, Rotor Nut. Ford specifically says these are not to be reused, so when you take them off, you're intended to replace them even if they still look good. However, many have reported no issues with reusing them with some loctite. The front and the rear require different ones.
Front: the OEM part is Ford F3LY-3B477-A (old code) or W710084-S439 (new code).
Rear: the OEM part is Ford FOSZ-4B477-A (old code) or W707772-S441 (new code). Note that if you get the FTBR bundle listed below, it comes with matched rear retainers and so you don't need these two.
Aftermarket Dorman retainers are available (615-098), but despite being advertised as and intended to be compatible, they aren't. You can read about the issue here:
www.tccoa.com
There's a solution to fix the Dorman nuts involving a M24 x 2.0 tap (see the above TCCOA thread), if you really want to use them instead of the Ford ones.
Rear Hub Swap
Cobra rear calipers actually use smaller pads than the MN12 rear calipers, and in any case the parking brake cables won’t hook up to Cobra calipers unless you fully disassemble both and swap the lever assemblies. As such, the rear calipers are typically left MN12 stock, and that's what's being assumed here.
1. Rear Hubs. You specifically need a pair of rear hubs for a Mustang Cobra, 1999-2004 range.
Full-tilt Boogie Racing's "SN-95 Cobra IRS Rear Hub Bundle" (FT 6555 Bundle) has what you need. While a bundle, it's still just one hub, so you need two.
The stock rear rotors are 10.125” in diameter, while the Cobra rear rotors are 11.65”. The stock rear rotors have an offset of 40mm, while the Cobra rear rotors have an offset of 45mm. Therefore, a bracket is required that relocates the stock caliper outward 19mm and towards the centre of the vehicle 5mm. While you can make your own brackets, the easiest thing is to get a pre-made set:
2. Brake Caliper Relocation Kit by Super Coupes Unlimited (SCU).
Available through SCU's page on Facebook Marketplace (send a PM to that page). Skip the hub rings add-on option, because with the full hub swap the rings aren't needed.
Even with the bracket, some modifications to the spindle and caliper are required. As the arc of the Cobra rear rotors is greater than the arc of the stock rear rotors, the caliper must be modified to maintain 2-3mm clearance between the outer edge of the rotor and the inside of the caliper, and you will have to file away a little bit on the outer edges of the spindles to give the larger rotor clearance. SCU has a full guide with pictures on their Facebook page that shows you how to mount the bracket and what grinding you have to do to make it all work out. The "MN-12 to SN-95 Bolt Circle Change" page linked at the start goes over this as well, albeit with a homebrewed bracket solution.
In addition, the stock caliper retaining bolts cannot be reused: M12-1.75 x 30mm Allen head cap screws must be used instead.
3. Rotors. Again, ones specifically for a Mustang Cobra are required, 11.65". The date range for the rotors is broader than that of the hubs: 1994-2004. I used these:
Front Hub Swap
This is where the assumption that you have large wheels comes in. With wheels of at least 17" you can go with a Cobra brake setup on the front, which is both more powerful than stock (13" rotors vs 10.85"; 11.52” if you have the Sport) and easier to install than many of your other options.
(Note from supergordo: "The general design of the wheels matter too. I have a set of 17"s that fit good and a set of 18" wheels I needed to put a 5mm spacer in to keep the wheel spokes from hitting the caliper.")
1. Front Hubs. You just need a pair of generic SN-95 Mustang front hubs (1994-2004), like FT 6455 from FTBR (same FTBR link as above), and they just bolt in. In other words, you don't need Cobra-specific hubs for the front, and no pressing is involved. However, the rotors and calipers are Cobra-specific.
2. Rotors. You're looking for 13" rotors compatible with 1994-2004 Mustang Cobras. I used these:
3. Calipers. Unlike the rear, your front calipers need to be changed out. They must match the rotors, so you need 1994-2004 Mustang Cobra-specific calipers. I used this set, which has both calipers, 40mm pistons, come with the brackets, has pads as an add-on if you need them, and even has a colour choice:
www.doctordiff.com
4. Brake Lines (optional). While you can reuse your stock lines if you want, because of the Cobra brake upgrade you have to grind the banjo block a little bit to clear the front caliper on the passenger side (not both sides). This is apparently rather simple, but you can skip any grinding here if you upgrade to stainless steel brake lines, which have rounded corners on the end that let them fit without issue:
Their webpage is vague, but each of these is a full kit for the car, rather than a single line, so you only need one.
Between how popular this mod is, and the fact that there's multiple valid ways to do it, there's about a hundred threads for this. But the problem is there's about a hundred threads for this: there doesn't seem to be one that is a one-stop shop, and some of them are quite old in terms of part options, or have info that another won't have, or have info that's unclear or apparently contradictory (often because of the fact that there's multiple ways to do this).
This particular thread is assuming that you:
1) want to swap your stock wheel hubs with Mustang hubs, rather than just drill the stock ones out
2) have large (17"+) wheels to go on those hubs when you're done
3) want to upgrade your brakes as well as your hubs
Key Article:
MN-12 to SN-95 Bolt Circle Change
Refer to this article for the step-by-step process. As it's so useful, in case the page ever gets deleted I've converted it to PDF and attached it to this post (see bottom).
Special Note: 89-92 Birds vs 93-97 Birds
For owners with Birds from 89-92, you must first upgrade to T-bird spindles from 1993 or later. The older spindles are different and don't work with these procedures. See this short thread for spindle upgrade information.
Generic Tools / Parts
The biggest hurdle here is the need for a hydraulic press for the rear hubs: that bit isn't something you can just do on your own. The rear hubs are pressed into the rear wheel bearings, which are pressed into the knuckles. However, you can take the two sets of rear hub/bearing/knuckle combos to a shop to have this done: you don't need the car present to get the pressing done.
20 lug nuts (1/2"-20 size).
8 Allen head cap screws (M12-1.75 x 30mm) and 8 M12 x 1.75 hex nuts.
250 ft-lb torque wrench.
2 Wheel bearing retaining rings (OEM Ford N803955-S or Dorman 933-954). The article mentions these, but doesn't tell you what to do with them. These are for the rear, at the knuckle; the fronts don't use them.
4 Retainers.
Also known as Axle Nut, Spindle Nuts, Retainer Nut, Hub Assembly Retainer Nut, Hub Nut, Rotor Nut. Ford specifically says these are not to be reused, so when you take them off, you're intended to replace them even if they still look good. However, many have reported no issues with reusing them with some loctite. The front and the rear require different ones.
Front: the OEM part is Ford F3LY-3B477-A (old code) or W710084-S439 (new code).
Rear: the OEM part is Ford FOSZ-4B477-A (old code) or W707772-S441 (new code). Note that if you get the FTBR bundle listed below, it comes with matched rear retainers and so you don't need these two.
Aftermarket Dorman retainers are available (615-098), but despite being advertised as and intended to be compatible, they aren't. You can read about the issue here:
Watch out for junk dorman spindle nuts!
Rear Hub Swap
Cobra rear calipers actually use smaller pads than the MN12 rear calipers, and in any case the parking brake cables won’t hook up to Cobra calipers unless you fully disassemble both and swap the lever assemblies. As such, the rear calipers are typically left MN12 stock, and that's what's being assumed here.
1. Rear Hubs. You specifically need a pair of rear hubs for a Mustang Cobra, 1999-2004 range.
Full-tilt Boogie Racing's "SN-95 Cobra IRS Rear Hub Bundle" (FT 6555 Bundle) has what you need. While a bundle, it's still just one hub, so you need two.
The stock rear rotors are 10.125” in diameter, while the Cobra rear rotors are 11.65”. The stock rear rotors have an offset of 40mm, while the Cobra rear rotors have an offset of 45mm. Therefore, a bracket is required that relocates the stock caliper outward 19mm and towards the centre of the vehicle 5mm. While you can make your own brackets, the easiest thing is to get a pre-made set:
2. Brake Caliper Relocation Kit by Super Coupes Unlimited (SCU).
Available through SCU's page on Facebook Marketplace (send a PM to that page). Skip the hub rings add-on option, because with the full hub swap the rings aren't needed.
Even with the bracket, some modifications to the spindle and caliper are required. As the arc of the Cobra rear rotors is greater than the arc of the stock rear rotors, the caliper must be modified to maintain 2-3mm clearance between the outer edge of the rotor and the inside of the caliper, and you will have to file away a little bit on the outer edges of the spindles to give the larger rotor clearance. SCU has a full guide with pictures on their Facebook page that shows you how to mount the bracket and what grinding you have to do to make it all work out. The "MN-12 to SN-95 Bolt Circle Change" page linked at the start goes over this as well, albeit with a homebrewed bracket solution.
In addition, the stock caliper retaining bolts cannot be reused: M12-1.75 x 30mm Allen head cap screws must be used instead.
3. Rotors. Again, ones specifically for a Mustang Cobra are required, 11.65". The date range for the rotors is broader than that of the hubs: 1994-2004. I used these:
Front Hub Swap
This is where the assumption that you have large wheels comes in. With wheels of at least 17" you can go with a Cobra brake setup on the front, which is both more powerful than stock (13" rotors vs 10.85"; 11.52” if you have the Sport) and easier to install than many of your other options.
(Note from supergordo: "The general design of the wheels matter too. I have a set of 17"s that fit good and a set of 18" wheels I needed to put a 5mm spacer in to keep the wheel spokes from hitting the caliper.")
1. Front Hubs. You just need a pair of generic SN-95 Mustang front hubs (1994-2004), like FT 6455 from FTBR (same FTBR link as above), and they just bolt in. In other words, you don't need Cobra-specific hubs for the front, and no pressing is involved. However, the rotors and calipers are Cobra-specific.
2. Rotors. You're looking for 13" rotors compatible with 1994-2004 Mustang Cobras. I used these:
3. Calipers. Unlike the rear, your front calipers need to be changed out. They must match the rotors, so you need 1994-2004 Mustang Cobra-specific calipers. I used this set, which has both calipers, 40mm pistons, come with the brackets, has pads as an add-on if you need them, and even has a colour choice:
'94-'04 Mustang Cobra Front Calipers
Pair, NEW '94-'04 Mustang COBRA front calipers are built with 10 mm x 1 banjo threads and large 40.48 mm pistons. BLACK POWDER-COATED front calipers fit ONLY '94-'04 Mustang COBRA with 13" front rotors (SN95). These calipers DO NOT fit Mustang Base/GT mod
www.doctordiff.com
4. Brake Lines (optional). While you can reuse your stock lines if you want, because of the Cobra brake upgrade you have to grind the banjo block a little bit to clear the front caliper on the passenger side (not both sides). This is apparently rather simple, but you can skip any grinding here if you upgrade to stainless steel brake lines, which have rounded corners on the end that let them fit without issue:
1993 1994 1995 1996 1997 Ford Thunderbird & Mercury Cougar STOPFLEX Braided Hose Kit - Includes instruction seet
1993 1994 1995 1996 1997 Ford Thunderbird & Mercury Cougar STOPFLEX Braided Hose Kit - Includes instruction seet
classictube.com
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We always had trouble getting 10 people to do a group buy. 
