Thunderbird to Mustang Hub Swap

Stanley

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1997 Thunderbird 4.6L V8
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Might as well round up some existing information while I'm at it.

MN-12 to SN-95 Bolt Circle Change

Mustang Hub Swap DIY as of 2017
(Thread duplicated here)



I have a '97 Bird with the Sport package. I'll be running 19"x9" rims (because that's what the car came with), if that matters.

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 contradictory info or info that another won't have. So I hope you won't mind if I put in some part numbers/pages for verification along with my questions.

Rear Hub Swap
1. Cobra Rear Hubs, 1999-2004
FTBR has a "SN-95 Cobra IRS Rear Hub Bundle" on that page that looks to be what I need.
2. Brake Caliper Relocation Kit by Super Coupes Unlimited (SCU), without hub rings (because with the full hub switch the rings aren't needed)
Available through SCU's page on Facebook Marketplace

First: Will these rotors fit after the swap?
(I ask because I've seen two separate listings for these that only give 2003 as a compatibility date, not 1999-2004)

Second: One of the many threads had this note, and I don't see it in any of the other threads so I want to make sure it's accurate:
"All of these [rear hub drilling/swap] options keep your stock 93+ MN12 rear calipers, but for the cobra rear brake rotors, you will have to file away a little bit on the outer edges to give the larger rotor clearance."
Filing away what, specifically? As I'll be having a shop do this rather than myself, is there anything more specific I should tell them?

Front Hub Swap
The front hub swap seems to be much cleaner: just get a SN-95 front hub like FT 6455 from FTBR (same link as above) and it just goes in.

The brake portion of this, however, seems to be a pain in the ass. General consensus seems to be that PBR calipers are the way to go. But the KVR 10.8" calipers that were apparently a direct bolt-on no longer seem to exist (just like KVR itself). The use of generic Mustang ones requires a bunch of adjustment grinding that I'm not sure a local shop would be willing to do, as detailed at https://www.tccoa.com/threads/mustang-pbr-calipers-to-thunderbird-conversion-and-problems.57171 (though I suppose I could show a shop the TCCOA explainer thread and ask). So right now I'm looking to just swap the front hubs but otherwise stick with the stock (Sport) brakes on the front unless there's a front brake upgrade that sits in between Sport and PBR in terms of difficulty.

Third: That would mean I only have to switch to SN-95 rotors, and as I understand it any generic 1994-2004 Mustang front rotor will do here, rather than something Cobra-specific. Correct? Such as this:

Thanks.
 
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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 identification purposes rather than an intention to actually buy the item 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.
 
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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