Thunderbird to Mustang Hub and Brake Swap

Stanley

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1997 Thunderbird 4.6L V8
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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. Having since done the swap, the parts listed below are 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 calipers, pads, and rotors--front and rear--in addition to your hubs

If you simply want to upgrade your front calipers and pads while keeping the rotors and hubs stock, and skip the rear altogether, you want a different upgrade procedure detailed here:



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.



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).



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). You'll be tossing your old ones. Torque these to 100 ft-lbs.

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 for the fronts (615-098), but despite being advertised as and intended to be compatible, they aren't. You can read about the issue here:
There's a solution to fix the Dorman nuts involving a M24 x 2.0 tap (see the above TCCOA thread), if you need to use them instead of the Ford ones.



Rear Hub Swap
The parking brake cables won’t hook up to Cobra rear calipers unless you fully disassemble both and swap the lever assemblies, and in any case Cobra rear calipers actually use smaller pads than the MN12 ones. 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, you need to relocate the stock caliper outward 19mm and towards the centre of the vehicle 5mm. While you can do this by making your own relocation kit, the easiest thing is to get a pre-made one:

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 that add-on isn't needed.

Even with the kit, 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 clearance for the larger rotor. SCU has a full guide with pictures on their Facebook page that shows you how to mount the relocation 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. If you get the SCU bracket kit it comes with the right ones that match the kit.

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, the front hubs are not Cobra-specific, 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. The set uses 40mm pistons, come with the brackets, has pads as an add-on if you need them, and even has a colour choice:

1994-98 Mustang calipers used 38mm pistons, vs 40mm in the 1999-2004 calipers, so if the above doesn't work for you and you see a choice between 94-98 and 99-04, go with the latter.

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.
 

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DLF was a great guy. I remember the battle we had with koni wbw, trying to get them to build one more run. They came back with an offer to build them if we could get 50 sets. :) We always had trouble getting 10 people to do a group buy. :) PST gave me the Group price for both the drive shafts I bought after the gp.
 
First. No. those are non ventelated GT/V6 rotors and our brake calipers are designed for thicker vented discs. the rotor you want is the 94-04 COBRA rotor, diameter is 11.65" and the visual tell is they're ventelated

Second: The filing or grinding needs to be done to the spindles since there will be a bit of interference with the bolt bosses on the relocation brackets otherwise. its pretty obvious when you see them, they're right above the existing bolt holes for the factory calipers and almost look like they're designed to be cut off

There's two formulas of PBR, the 00-04 GT/V6 type on the 10.8" rotor and the 94-04 Cobra type on the 13" rotor. Since you're buying all this from scratch and have big wheels to clear them just co with Cobra, the price will be a wash and there's no clearance issues requiring grinding like the smaller PBRs.

Drilled and slotted rotors don't do anything for braking performance, I'd just seek out standard Brembo Cobra rotors, IIRC raybestos premium line are them(at least they were).
 
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The drilled rotors help brake fade on my gs750, but the mn12's I've never noticed an issue with fade on the pbrs; the stock rotors, calipers, and 20 yo fluid is prime for it. The water in the fluid becomes steam, and the brakes go bye, lol. That was about 2001, finding out how much I hated the stock brakes, on sr 199 past brushy mountain. It's a great road for a bike, but rough on a car. I've seen a whole group of bikes go flying off the road in one corner, lol. Thankfully, my bike is slow, and won't go that fast in that curve, and I know that, lol. My bikes are old school, but the major improvement to go along with the DOHCheads, was dual-piston calipers with drilled and vented rotors. a 550lb bike is a lot like a 3800lb car. :)
 
This beats the hell out of trying to parse a few dozen other threads (none of which had all of this detail): very helpful, gents.

Okay, it seems there's 38mm and 40mm piston versions of the front Cobra brakes. I found this set that has calipers, pads, brackets, bolts, a colour choice, and the 40mm pistons all together:

While for rotors I believe the following fit the hubs from the OP:
Back 11.65": https://www.summitracing.com/parts/ceb-120-61046
Front 13": https://www.cjponyparts.com/raybestos-disc-brake-rotor-front-cobra-mach-1-bullitt-1994-2004/p/BR71/

If those all check out, I'll be getting started.
 
Yep that looks good, I wouldnt worry too much over 38mm vs 40mm calipers but it seems like most of the cores in circulation at this point anyway are 40. You might find better pricing for the calipers on rockauto
 
I'm in Canada, so a lot of time I'm just posting links for verification purposes rather than an intention to actually buy the item from that place / at that price. I have to jump through a lot of hoops to cut down on shipping and so my choices are limited, because US sellers tend to treat Canada like Abu Dhabi or the Crab Nebula.
 
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Some mail places will drop ship to get around such things.
 
What the heck happened to summit? their prices seem pretty out of whack to others.
 
Grinding is also not necessary if you replace your brake lines with SS ones that have rounded corners on end that the banjo bolts fit through.
Classic tube made them and spinningwheelsc was the main distributor, IIRC.
 
Are they still sold? I remember a few years ago they fell on hard times and there was talk of them closing up.
 
If spinningwheels is dead, call classic tube up directly.

Or bring the ends of a stock line to any hydraulic shop and ask them to make it for you.
 
Something we need to save from the old forum is the contact info for the widow of the guy that supplied the stainless lines; I'd like to support her. I'll look and edit this post. You can really feel the difference with the stainless lines; I kinda drive with my toes, braking and accelerator. )

Is this the right line, or do I need to call them?

 
Something we need to save from the old forum is the contact info for the widow of the guy that supplied the stainless lines; I'd like to support her. I'll look and edit this post. You can really feel the difference with the stainless lines; I kinda drive with my toes, braking and accelerator. )

Is this the right line, or do I need to call them?

Greg, you are talking about Diane at Spinning Wheels right?
 
Yes. Do you have that? I looked at the other place; I remember a bunch of us discussing it.
 
I'd be very interested in getting a set of those lines if someone can dig up a link, since I have everything else needed for the swap sitting in my garage right now and haven't started yet.
 
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Something we need to save from the old forum is the contact info for the widow of the guy that supplied the stainless lines; I'd like to support her. I'll look and edit this post. You can really feel the difference with the stainless lines; I kinda drive with my toes, braking and accelerator. )

Is this the right line, or do I need to call them?

That's the right product but they have versions for both rear disc and rear drum so maybe it's necessary to call.
 
There's two formulas of PBR, the 00-04 GT/V6 type on the 10.8" rotor and the 94-04 Cobra type on the 13" rotor. Since you're buying all this from scratch and have big wheels to clear them just go with Cobra, the price will be a wash and there's no clearance issues requiring grinding like the smaller PBRs.

Slight bump here. You mention needing big wheels to do this right. I know the 19s I have right now are good, but what's the minimum size you can have and still get away with this front Cobra brake swap with absolutely no extra issues? I found a reference once but of course can't locate it now.
 
Slight bump here. You mention needing big wheels to do this right. I know the 19s I have right now are good, but what's the minimum size you can have and still get away with this front Cobra brake swap with absolutely no extra issues? I found a reference once but of course can't locate it now.
17"
 
17" is the minimum. But the general design of the wheels matter too. I have a set of 17"s that fit good. aand a set of 18" wheels I needed to put a 5mm spacer in to keep the wheel spokes from hitting the caliper.
 
Grinding is also not necessary if you replace your brake lines with SS ones that have rounded corners on end that the banjo bolts fit through.
Classic tube made them and spinningwheelsc was the main distributor, IIRC.


Are these the lines/hoses you were talking about? They don't mention anything about steel so I'm not entirely sure.

If these are right and you're doing the swap, how many of these do you want? A full set of four?
 
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That looks correct. StopFlex is what they call their line of stainless hoses.


I'd search back through my old receipts to see what I paid Spinningwheels-SC, but I'm not that curious. I remember it was in the low-to-mid-100s, so $171 seems about right compared to what Victor sold them for years ago once you account for inflation.
 
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These make a huge difference in feel, I really liked the upgrade. They were so good in fact, that I upgraded one of the cycles. :) You do not want to lockup the front wheel, so I changed it back to rubber. :) The car is great tho.
 
So I have all the parts for this but haven't been able to set aside the money for labour. And now I'm in another city and I'm told the bearings on three out of my four wheels are going because of the spacers the previous owner mounted to fit my Mustang GT wheels.

Long story short, is it possible to keep the existing MN12 brakes, rotors, calipers, etc--absolutely everything else MN12-stock except the wheels--and just change the hubs to Mustang hubs (so I can mount the wheels correctly)? No special drilling or grinding, no special brackets, etc? I want to keep this as cheap as possible (and simple, because the guys I have aren't thrilled about non-standard work).

Thanks.
 
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You can keep stock calipers and pads, but the rotors will have to match the hubs. For the front, a pair of stock 99 Mustang GT rotors will work with the stock non-sport Tbird caliper and pads, however for the rear you will have to either redrill the rotor to the new bolt pattern or get the brackets to run the 99-03 Cobra rear rotors, which will work with the stock Tbird rear calipers and pads.
 
Crap, I was afraid of that. Okay, thanks for the quick turnaround: it's appreciated.
 

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