If you've ever wondered why Fox cars have 4-lug bolt patterns, well, you're not alone. Apparently it was a weight (and cost) saving idea that actually made it through the ranks and into production. Plus it was the late 1970s and the U.S. government was optimistic that the metric system would catch on (that's why some Cougars have the infamous TRX metric rims). You have to admit, it sure is easy to change a tire with just 4 lugs. But if you crave for a little normalcy or just want a better selection of newer modern rims then 5-lug is the way to go. There is a whole new world of possibilities for rims when you have a 5-lug pattern. For example, just about any 1994-2004 Mustang rim will bolt right up with no problem. Or if you're going retro, a set of BBS 16" spoked Mark VII rims look sweet. The choice is yours---if you've already found that perfect rim, but need to swap to 5-lug, then this is the section for you.

Ford uses the 5 lug, 4.5" bolt pattern on almost all of its 5-lug rear drive vehicles. The only exceptions, ironically, are the 1989-97 T-Bird/Cougar and 1993-98 Mark VII, which use a very unusual FWD 5-on-4.25" pattern (from the Taurus, Sable, Continental and Windstar).

Stock Rotors (10")
Changing front rotors on these cars is very, very simple. Until recently, though, there really wasn't a pre-made bolt-on solution for 10", 5-lug rotors. Not long ago we were contacted by Brian Portez of Complete Brake Service in Columbus, OH. Brian says that his company has 10" 5-lug rotors for the Fox Cougar/Thunderbird (and 4-cylinder Mustang) in stock for about $120 US per pair. This is about the only place that has come forward about these rotors and the only place we've ever heard that carries them. They'll even ship the rotors anywhere. The price ($60/each US) is very competitive. You can visit their website or you can call 1-800-581-2339 (locally 614-221-4888), and ask for Brian.

Jason from FL writes: "Just installed the 5-lug 10 inch rotors. Fit was perfect, quality seemed excellent. Price was good at $129.00 U.S. plus shipping. I got rotors, new inner and outer bearings, seals and dustcaps. Shipped to my door in 3 business days. Thumbs up from me!"

FRONT BRAKE ROTORS, UPGRADE TO 5-LUG

Fox Rotors (11")
If you have already upgraded to the 11" rotors then the only direct swap 11" 5-lug front rotor will be from the Lincoln Mark VII (~10 49/64"). Keep in mind that most Mark VII's had ABS brakes, which means that an exciter ring was part of the rotor hub. This significantly increases the cost of the rotor; however, you should be able to find a Mark VII rotor for a car without ABS. If you have trouble in that department, Ford Racing/Motorsport's 5-lug kit (M-1102-C) provides the rotors and seals. Also you will need at least a 15" rim to clear the brakes. (If you haven't upgraded to 11" Fox brakes but are planning on doing so, see the information here).

SN95 Mustang Rotors (~11")
Since the newer Mustangs use a modified Fox suspension up front, you can use that car's braking system on your Cougar. What you have to understand is that it's a little different than what's on your car. In 1994 Ford opted to use the hub-type system on the front of the Mustang, meaning that the rotor does not have studs, but rather holes to slide over the hub that's bolted to the spindle. It's not that major of a difference but it does mean that you're dealing with different parts than what you're probably used to. However, you will happy with the relative ease of installation and assembly, and the comfort of knowing that you have a more modern system on your car.

The biggest advancement with SN95 Mustangs is that they all have comparatively large rotors from the factory, roughly 11" in diameter. Again, you will need at least 15" rims to clear the braking components. You can use the following parts:

• Spindles - Any 1994-up Mustang can provide the spindles. However, there is a difference between the two major styles. In relation to the standard Fox spindle, the 1994-95 Mustang spindle moves the ball joint 20mm forward, 27mm outward, and 1mm down. The wheel center moved 17mm forward, 23mm outward, but is the same height. The outer tie rod end is moved 20mm forward, 41 mm outward, and 4mm up. The second style is the 1996-2004 Mustang spindle, which compared to the earlier '94-'95 spindle, has the lower ball joint moved 1mm rearward, 5mm inward, and 2mm down. The wheel center also moved 1mm rearward, but is the same width and height. The inner tie rod end is the same fore/aft and width, but moved down 28mm. This may all sound confusing, but in a nutshell, the 1996-2004 spindles lower the point where the tie rod attaches by about 1", and also pushes the spindles out slightly. Essentially they're meant for lowered cars. They are more conducive for performance driving (autocrossing, etc.) but will require slightly modified alignment settings, possibly caster/camber plates, and a bump steer kit is recommended. They also have a revised casting that will allow for larger 13" Cobra brakes later on, should you choose to do so. The 1994-95 spindles work perfectly well with stock caster/camber settings on a Fox Cougar/Thunderbird at stock ride height. Again: non-lowered car, 1994-95 spindles. Lowered car, 1996-2004 spindles. Do not mix 1994-95 and 1996-2004 spindles on the same car! You must get a matching pair.
• Calipers - Any 1994-up Mustang can provide those, so long as they match the rotor size (see rotors below).
• Brake Lines - It may be possible to reuse yours, but if not, then 1994-up Mustang ones can be used.
• Tie Rods - You will need to change at least your inner tie rods to SN95 (1994-04 Mustang) specs. You can try to use SN95 outers first, but most people report having to change the inners as well. If you're lowering or have already lowered the car, you should go with a good quality bump steer kit in place of tie rods. Jeremy writes, "Fox inner/outer tie rods have SAE threads. SN95 inner/outer tie rods have Metric threads. If you go with SN95 brakes you must change both inner and outer."
• Ball Joints - You will need to change ball joints to SN95 specs. If you're keeping the stock ride height, the stock pieces are fine. Otherwise we'd highly recommend Steeda's X2 ball joints for lowered cars.
• Hubs - This is a sealed unit that contains both inner and outer bearings, and all seals. It simply slides over the hub and is bolted down with one large nut beneath the dust cap. Any 1994-up Mustang can provide the hubs; they're all the same. New they are about $70 US each. Ford sells remanufactured units (check dealership for pricing).
• Brackets - These hold the caliper to the spindle. The system is designed for easier brake size upgrades; for example, if you were to ever go from 11" to 13" Cobra rotors, the appropriate bracket change is also needed. Make sure your brackets match the calipers and rotors (see below). Bracket bolts (2 per side) are metric!
• Pads - Again, these must match the caliper (see below).
• Rotors - BE CAREFUL. With the "New Edge" styling of the Mustang in 1999, Ford also made suspension and braking changes with the Mustang across the board. The front rotors increased in size then, and the calipers went to a dual-piston design. Therefore, if you are using 1994-98 calipers then you must use 1994-98 rotors, pads and brackets. And if you're going with 1999-up calipers then obviously you'll need 1999-up rotors, pads and brackets. It is really your choice as to which years' system to use, so long as you understand that everything must match. A lot of people are opting for the 1999-2004 braking system just to get the better calipers.

Mustang Cobra Upgrade (13")
If want to upgrade to a killer braking system, the Cobra 13" disc brake kit (FRPP p/n M-2300-K) is a very popular choice and probably one of the most affordable. It's basically the same brake setup as the '95-up Cobras (and the Bullitt/Mach I), and it comes complete with most everything you'll need to do the job. You will need at least 17" rims to clear these brakes (5.75" backspacing). Essentially the upgrade is just like the 11" SN95 upgrade outlined above, with these exceptions:

• Calipers - You actually have several choices, thanks to Ford. They opted to use the braking system designed by Australian manufacturer PBR on the Cobra and Bullitt. Therefore you can use the 1995-up Cobra caliper (black with white COBRA letters on the front) or the 2001 Bullitt caliper (red with a silver Pony on the front). Or, if you want to be different, you can use a 1988-96 C4 Corvette PBR caliper (silver and finned) made for 13" rotors.
• Brake Lines - It is highly recommended that you use Russell street-legal stainless steel brake lines. Factory Cobra lines were notorious for bad pedal feel.
• Banjo Bolts - The PBR caliper uses a metric banjo bolt. If you cannot obtain these bolts from Ford then take a trip to the GM dealer and get them for a C4 Corvette (1988-96 vintage).
• Brackets - 1995-up Cobra. Bracket bolts (2 per side) are metric!
• Pads - All of the PBR 13" calipers use the same pad so a Corvette pad fits the Cobra, and vice versa. Bad news is, they aren't cheap. The ultimate in pads are NAPA Ceramix, which are very quiet and produce much less brake dust than any other pad out there, but cost around $150 US. Shop around for pads if price is a factor.
• Rotors - DO NOT use pre-1999 Cobra rotors as they are notorious for warping prematurely. These faulty rotors were replaced in 1999 with much stronger Brembo 13" units. You can get them new at the Ford dealer for roughly $100 each. You also have choices in the aftermarket, such as slotted or cross-drilled, from a variety of manufacturers.

You can also purchase everything needed to convert over to the full 13" front/11.65" rear Cobra braking kit from Ford Racing. This is the M-2300-K kit and even includes rear axle shafts (for Mustangs only). The list price is a whopping $2100.00 US....which is exactly why we'd recommend shopping around and piecing the kit together yourself. You will save a ton of money that way.

The M-2300-Q/R kit includes the front brake upgrade to 13" Cobra specs (Q if you use 1994-95 spindles, R if you use 1996-up). The kit contains only rotors, calipers, pads and brake hoses; you must provide the spindles, hubs and brake dust shields. Its list price is $695.00 US and is really not bad for what you get. Likewise, you can complete the system with the separate rear 11.65" brake kit, M-2300-M, which lists for $189.00 US (double check the pricing, as that seems a bit low). It includes the rotors, calipers, pads and all mounting brackets.

Misc. Aftermarket Front Brake Upgrade
If none of the above appeals to you, you'll probably want to check out manufacturers like Brembo, SSBC and Baer in this case. The good news is, anything that fits a 1979-up Mustang will work on your car. So that means multi-piston, exotic rotor systems can definitely be adapted to a Fox Cougar/T-Bird.

REAR

In back, things do get a bit trickier but it's not nearly as difficult as you've probably heard. What is true is that you must change the axle shafts to those with a 5-lug pattern. Then you must get the appropriate 5-lug brake drum (stock) or disc brake rotor (upgraded). Really, that's it in a nutshell.

Axle Shafts
Now you can have your stock shafts machined for the 5-lug pattern, but as affordable and plentiful as new or used 5-lug axle shafts are these days, it makes more sense to search those out. Regardless of your model year 1983-88 and your rear end width, these axle shafts will directly swap into your Cougar's rear axle:

• 1994-98 Mustang-width axle shafts (~ 29 15/16", 7.5" or 8.8")
• 1983-92 Ford Ranger pickup axle shafts (2 driver's side, ~29 5/8")
• 1986-97 Ford Aerostar minivan (2 passenger side, ~29 5/8").

All stock Ford passenger car rear ends of our era had 28-spline axle shafts. If you need to see more specific information concerning rear end widths, axle shafts, and brake configurations, or simply need photographic references, please see the thread posted here. You can also visit this site for a chart with measurements.

REAR BRAKE DRUMS, STOCK SIZE

9" Drum Brakes
Most Cougars from 1983-88 had the standard 9" rear drum brakes, as denoted by the finned side profile. Now there were two types of drums: those used on 1983 through Nov. 1984 (mid-85), and those used from Nov. 1985 (mid-85) through 1988. The earlier drums had a large hat section bump out. We haven't found any stock 5-lug drums with that larger hat section. You'll probably have to get your drums machined with the 5-lug bolt pattern.

For mid-85 through 1988 owners, all you will need is new 9" 5-lug drums from either a Ranger or Aerostar. You can leave your stock backing plate and old hardware on the rear end. All there is to it---no other mods necessary.

10" Drum Brakes
The 10" drum came standard on all 1988 XR7's, and possibly other cars. The side profile of a 10" drum is totally smooth. Unfortunately we don't know of a direct-swap 10" 5-lug drum although it may be possible that Rangers had them as well. You can simply get your drums machined for the 5-lug pattern to solve the problem. It's possible that there is a 10" 5-lug drum out there waiting to be swapped in. If you do find that information, please contact us so that we can share that info with everyone here.

REAR BRAKES, UPGRADED

1987-88 Turbo Coupe 10" Rear Discs
Say you've already swapped in a Turbo Coupe rear with its stock 10" disc brakes. What to do then? It's a little tricky if you want to keep vented rotors. Eric writes, "I had my stock TC vented rotors machined to accept the 5-lug pattern, and used 1994-98 Mustang axle shafts. But I found out that the center hole in the rotors were too small for the hub on the flange....so they had to be machined out. Then the flange on the axle would not allow the hub of the stock rotor to seat properly. So the shafts came back out and the flanges had to be machined down to a 45 degree bevel. Only then could I bolt everything back up. Yes, it was a royal pain and yes, it was expensive. The job got done, but it was a real trial to keep the stock TC rotors with 5-lug."

It's probably more economical to buy a 1994-98 Mustang rear braking system (see below) and install that, although the rotors would be solid. That requires removal of the TC mounting plate for the caliper bracket. Since it's tack-welded on, you'll need to hammer it off. All of the more modern Ford rear ends with disc brakes use a clamp-style hold down for the brackets, similar to a muffler clamp. Then you can install the rest of the SN95 components without a hitch. You will be downgrading to solid discs though. If you want vented discs, the ones found on the Mark VII or newer Cobra can be used with the same mods to the bracket mentioned above.

1984-92 Mark VII Rear Discs
The Mark VII was one of the first cars in the U.S. to offer ABS braking, which usually requires 4-wheel disc brakes. Not all Mark VII's had rear discs though---some had drums, so be careful when checking them out. The Mark VII, as with a lot of Lincoln components, had their own unique 10.5" rear discs through 1990. This means you would need to use Mark VII rotors, calipers, pads, brackets and bolts. From what we understand it's not simple to do the Mark VII rear disc swap.

1994-Up SN95 Mustang Rear Discs
If you have a Turbo Coupe rear and don't want to go through the hassle of machining the rotors for the 5-lug pattern, or if you just want to make everything match with your current rear end, the newer SN95 Mustangs can provide a very nice rear disc braking system for your car. The beauty of the system is that it uses Turbo Coupe-style parking brake cables, making installation easy on your car. The stock 1994-98 Mustangs had a ~10" solid rear rotor with a small Varga caliper. In 1999 Ford bumped up the size to almost 11". To get either system to work on your car you will need the calipers, rotors, brackets, bolts, backing plates and pads. Make sure that you get all the parts from the same ear car---do not mix parts from a 1996 with a 2000, in other words. See above for the appropriate axle shafts needed.

1995-Up 11.65" Mustang Cobra Rear Discs
The Cobras, Bullitts and Mach I's are the only SN95 cars to use vented rear discs. You cannot use a Turbo Coupe/Varga style caliper with the Cobra rear disc; you must use an SN95 rear caliper at least, possibly Cobra-only. Also, you must use Cobra mounting brackets available at MPS. Everything else is similar to the Turbo Coupe/SN95 solid disc info as outlined above.

What happens if you want to directly swap in a 5-lug rear end? Some great examples are below. Keep in mind that there may be modifications necessary to your braking system in order to swap in a new rear axle.

5-Lug, Rear Disc Brakes/1994-98 Mustang
Since the 1994-98 Mustangs and the 1985-88 Cougar/T-Bird basically have the same width rear axle, this is probably the most logical step. All mounting points are the same as what's on your car now, making this a very easy swap. The V6 Mustangs had the 7.5" rear end while all V8's had the 8.8", and all had at least a 3.08 gear. Keep in mind that all 1994-up Mustangs had disc brakes, but the rear rotors are solid, not vented. Only the Cobras had vented rear discs. To use a 1994-98 Mustang rear in your car you will need to install emergency brake cables from a 1987-88 Turbo Coupe.

5-Lug, Rear Disc Brakes/1999-Present Mustang
The SN-95 Mustang had a brake upgrade across the board beginning with the 1999 model year. This was because Ford opted to use the independent rear suspension in the Cobra. Since changes were in order for the entire chassis, Ford deigned this the perfect opportunity to address the issue of better brakes. And since the track was wider out back for all Mustangs, this becomes a very viable solution for those wanting a bit more stability, or for extra clearance of those ultra-wide rims. We believe that this 1999-up rear is the same width as the 1984-92 Mark VII rear. The axle shafts are at least an inch longer from previous SN-95 Mustangs, that much is certain. Also, all 1999-up Mustangs had at least a 3.27 gear. They should be plentiful in the near future. You would need to install emergency brake cables from a 1987-88 Turbo Coupe.

5-Lug, Rear Disc Brakes/1984-92 Mark VII
The Lincoln Mark VII was a much heavier car than our Cougars ever were, even with ours fully optioned. Therefore its rear axle is a very beefy piece, and it's also wider by about 1" per side to accommodate a wider track for better stability. The Mark VII was one of the only older Fox cars to have 5-lug wheels so it's the perfect solution for anyone wanting to get better brakes, gearing, a wider stance, and the 5-lug pattern in one shot. In general the Mark VII 8.8" rear axle came with a 3.27 gear and 10.5" vented rotors. Traction-Lok was an option though, so it's not a guarantee; check the axle tag to be sure. And some early Mark VII's even had drum brakes. Be sure you know what you're getting first. Again, all mounting points are identical to your car now. You would need to install emergency brake cables from a 1987-88 Turbo Coupe.

5-Lug, Drum or Disc Brakes/Ford 9"
Long the popular choice with drag racers, the durable Ford 9" rear axle is best suited for strip and heavy-duty street applications. "Bulletproof" is an understatement concerning these bad boys, and with any imaginable kind of component available (spools, gears, Detroit lockers, etc.), your budget is the only limit. In order to fit your Fox Cougar chassis, a custom-built 9" is usually recommended, although a Mustang unit will usually fit very well. This is one area that's definitely best left to a professional shop. If you're tubbing out your car, the narrowing of a Ford 9" should be no sweat for the pros.

CONCLUSION

Obviously, there's a little work involved with converting our cars over to 5-lug axles and brakes. But, using stock Ford or aftermarket parts, it can be done with dramatic results.

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