5 Lug Wheel Conversion for Fox Body Mustangs

There’s no denying that Fox Body Mustangs are some of the most desirable project cars in the Mustang world, and considering over two million of them were sold between 1979 and 1993, they’re easy to get your hands on if you’re looking for a car that you can customize so that it’s unique to you.

The only part on a Fox Body that isn’t as easy to customize is the wheels. While upgrading and customizing your rims is one of the first appearance modifications most Mustang enthusiasts want to make, our beloved Fox has one limiting factor when it comes to picking out the wheels of your dreams.

Its four-lug setup.

Reasons to Convert

Most aftermarket wheel options are five lugs, and whether you’re looking at a very specific set of wheels or disc brakes, you’re going to have to make the conversion from four to five lugs. Though this may seem a little intimidating, thousands of Mustang owners have completed this conversion. As long as you take your time and make sure you have everything you’ll need laying out for you in advance, there’s no reason you can’t convert your Fox Body to a five-lug setup.

On the other hand, if you want to keep your current setup, there are four-lug wheels available that can still improve your Fox’s looks without requiring a conversion. Whichever way you choose to go, you’ll be in great company.

Step-by-Step Guide

This guide will walk you through each step necessary to install five-lug wheels on your four-lug fox the right way so that you don’t lose a wheel at an inopportune moment.

It’s estimated that this installation will take you about four to five hours, but depending on how much experience you have, that can vary significantly.

The major parts that you’ll need are new five lug rotors for your front wheels, five lug rear drums, and a new rear axle and axle bearings. The primary ways people obtain the parts necessary for their new setup is either to purchase these parts, or get a set off of an SN95 Mustang that’s in a junkyard or has otherwise been relegated to a “parts vehicle” status.

In addition to these major components, you’ll also want to have your new five-lug wheels ready to go.

Required Tools:

• Lift or Jack and Jack Stands
• 1/4" Ratchet
• 8mm socket
• 3/8" Ratchet
• 1/2" Socket
• 17 mm socket
• 6mm socket
• Short extension
• Crescent wrench
• Hammer
• Pry bar
• Slide Hammer
• Bearing Installer
• Small Flathead screwdriver

1. Before doing anything, be sure to lift your Mustang. Remove the front brake caliper and caliper bracket. This involves removing the retaining bolts with a socket. These can be tight if you haven’t changed your brake pads or rotors in a long time, so you might need some lubricant. When the bolts are out, take care not to let the caliper hang by the brake lines. This can damage them and cause them to leak. Use a rope or strap to tie the caliper to the strut while you’re working. Also remember not to push the brake pedal when the calipers are off, as it makes reinstallation difficult.
2. Carefully remove the dust cover at the center of your rotor. Inside, you’ll find the cotter pin and bearing retaining nut. Remove each of these in preparation for the rotor removal.
3. Pull the rotors off. If you haven’t replaced them in a while, they might be tight, but a bit of a wiggle back and forth is all it should take. While they’re off, inspect your brake pad wear. Many people use this opportunity to replace their pads.
4. The exposed piece of metal in the center of where your rotor used to be is the spindle. Clean it thoroughly and then reapply fresh grease.
5. You’ll need to pack your wheel bearings with grease whether you’re using new bearings or reusing your old ones. There are two methods of doing this. The tool-free way is simply to get a wad of grease in your hand and work it through the bearing. The other way is to use a packer, a tool that can pack the bearing with grease easily.
6. Once your wheel bearings are packed with grease, you’ll want to grease the races themselves and then insert the grease-packed bearing. Then, you’ll insert the seal. You can use a piece of wood to ensure that your hammering is applying even pressure.
7. Mount the rotor onto the spindle and then make sure that it’s seated. Then, install the outer-bearing, and the rest of the parts you removed in step two.
8. After the rotor is in place, the next part to reinstall is the caliper. First, you’ll want to clean the new rotor to remove oil since that can damage the caliper over time. Grease the caliper’s slide pins as well and then tighten them up.
9. After repeating this process on both front wheels, it’s time to move to the rear. There, you’ll want to drain the differential oil. To do this, unscrew all of the bolts except the top one and then make sure you have a pan down to catch the oil. Pry the cover off and stand clear.
10. You need to remove the pinion rod retaining bolt, which holds the rear axles in place. To do this, rotate the rear wheels (with the transmission in neutral) until you see the retaining bolt.
11. Remove your rear brake drums. It’s important to ensure that your emergency brake is off for this step or else you’re likely to be very frustrated in a hurry. While your brake drums are removed, it’s a great opportunity to check out your brake shoes for wear and tear. It’s a good time to replace those as well since you already have everything removed.
12. Push both axles in slightly in to see the c-clip, which is what holds your axle in place. Remove this clip.
13. Pulling on either hub, remove your rear axle. You’ll want to do this with care. Repeat process on each side.
14. Remove the rear seal and axle bearing. You will need to use a slide hammer to get the rear bearing out, but you can rent one if necessary. Repeat on each side.
15. Install the new rear axle bearing. Use the bearing installer and hammer to push the bearing into place. Use the same steps to replace the rear seal. Grease is helpful in making sure that the bearing and seal are able to go in easily. When you’re finished, they should be flush with the outside edge.
16. Install your new axle. Avoid putting too much pressure or weight on your new seal, and guide the axle in gently.
17. Reinstall the retaining clips and pinion bolt that you removed initially. It’s a good idea to use lock tight on this bolt, since it’s what holds your axle in place and you don’t want it to back out.
18. Install your new five-lug rear drums and replace your differential cover. This is a great time to upgrade any parts here, but regardless make sure that everything is clean. Use a gasket maker along the edge of the differential cover and then tighten the bolts in a criss-cross pattern.
19. Fill the differential taking care to follow manufacturer’s recommendation.

Now, it’s time to install your new five lug wheels.

Choosing The Right Wheels

For the regular driver who just likes their Fox Body Mustang looking its best, the move to 5-lugs opens up a world of choice in aftermarket rims. Many modern Mustang rims will fit, but you always need to check first. Don’t just assume any 5-bolt wheels will fit. You have to take into account several factors:

• Bolt Pattern: There are several different five-bolt patterns on the market, and you need to ensure the lug diameter, spacing (compared to the other lugs) and thread pattern is the same as what you have installed
• Brake Clearance: Some newer original Mustang rims and aftermarket rims don’t have enough clearance within the wheel for the Mustang’s brake calipers and/or drums. We specify which models the wheels we carry are compatible with, so you can be sure before ordering. However, if you’re still not certain, ask us, and we’ll help you find out.
• Wheel Clearance: While not directly related to the 5-lug upgrade, chances are you’ll be increasing your tire size to match your new 5-lug wheels. Always make sure to check the clearance (both with your suspension travel and wheel well room) to ensure your new wheels won’t bottom out or scrub your fenders.

In some cases, your wheels might just require spacers to fit properly.

Compatible Modifications

If you’re willing to spend a little extra wrench-time, there are a few modifications that are easy to install at the same time as you do your five lug upgrades. The most obvious example is disc brake conversions.

It’s likely that you’ll notice many of the brake components of your Fox Body are starting to show their age, and you can replace them, or you can choose to upgrade entirely to four-wheel disc brakes for improved responsiveness and decreased stopping distance.

Video Tutorial

If you’re still on the fence, watch Bill and Brendan go through each of the steps to convert Bill’s Fox Body Mustang into a five-lug. Seeing someone complete each of the steps, while dispensing tried-and-true-tips and tricks, is a great way to get a feel for how challenging the project might be for you.

Though this is a moderately challenging modification, it’s a great way to change up your Fox and really opens up a lot of options for future improvements.

In the video, you'll hear Bill talk about some of the future improvements he plans to make, like disc brakes. All of these modifications become much easier when you've already layed down the foundation of converting over to five-lug wheels.

Enjoying Your New Wheels

Once your brakes are back in place (either original drum style or upgraded to discs), it’s time to bolt on your new 5-lug wheels! If your upgrade kit includes a new brake fluid reservoir, lines, and proportioning valve, these should all be installed at this point. After bleeding your brakes, you’ll want to go for a test drive. Always start off slowly in the driveway, applying your brakes several times moving forward and backward to make sure everything is seated and functioning properly.

The whole point of this exercise was to get a great looking set of five-lug wheels on your Mustang, so now that it’s accomplished, get out and enjoy it! With your new rims in place, your car will take on a whole new look. And if you’ve upgraded to lower-profile and/or wider tires, you’ll feel the performance benefit, too.