I am currently working on an overview on the parts necessary and the options and choices you will have doing your brake upgrade. I will list some of the specific combinations and parts needed to successfully upgrade your 1979-1993 Fox body Mustang to the more capable SN95 - 1994 and newer Mustang brake components. This will include swapping to 5 lug axles, use of the front & rear SN95 brake components, either GT V6 parts or the larger Cobra brake components. There are other ways of doing a bigger brake upgrade including the use of aftermarket kits from companies such as Baer, SS brakes and others but we will focus on using readily available (cheaper) parts! If there is something you would like added to this or if a necessary correction is needed, just send me an email with your comments. Take a look at my Avatar on the right. This is a picture of what Cobra front brakes and a coil over suspension looks like on a fox body Mustang.

1979-1986 and 1987-1993 Mustang 5 Lug conversion using SN95 Parts

Rear brakes components and axle choices:

Rear axles -  SN95 axles from a 1994-1998 Mustang V6, V8 GT or Cobra. These axles are .75 inches longer per side. If you use these axles then you may be limited to only 8.00 inch wide rear rims unless you want to modify your rear fenders for clearance.

If you want a wider rim and tire combination on the rear of your car then the use of the stock length axles is preferred. They can be obtained as "new" from manufacturers such as Superior, Moser and others. This is a wise choice if you are also planning on building a high horsepower setup as you will want stronger axles anyway. You can also choose to find Ford Ranger axles from the junk yard. No matter what stock length type axle you choose you will need to obtain a set of offset rear caliper axle mounting brackets to allow the proper positioning of the rear calipers. These are available from a variety of sources. We also have carried these at various times. Next consideration is whether you want standard Mustang V6/GT brakes with their 10 inch rear rotor size or if you want larger 11.65 inch Cobra rear rotors. This decision will determine what caliper to axle mounting bracket you will need. The Cobra brakes use a taller bracket to allow for the taller rotor. The bracket places the caliper up higher to provide proper positioning. Offset brackets are available for both GT and Cobra brakes. I normally recommend going to Cobra brakes unless on a budget as the GT/V6 parts are cheaper and more readily availible. Now on to the calipers. If you are doing GT/V6 brakes either the GT/V6 will work. They are identical. If you are doing a Cobra rear brake setup either the Cobra calipers or the GT/V6 will work for you also! You may have to provide just a small amount of clearance for the slightly wider Cobra rotor as the larger Cobra rotor is also a vented rotor. This also provided addtional cooling for the Cobra brakes which of course is better. Normally only a small amount of clearancing needs to be done. A small grinding stone, dremel tool, etc. will work out just fine. If it is too close the edge of the rotor will drag. This will be apparent just by turning the rear wheels when you start to assemble the brakes. Last thing to consider also is to properly space the rear caliper so that it is centered over the rotor when bolted down. The use of a thin washer as a shim between the caliper mounting bracket and the axle mounting bracket is common, quick and easy.

Master Cylinder Choices

1987-1993 Mustang

The most common choice for the 87-93 Fox Mustang is to use the 1993 Cobra MC. This is a part we do carry. It has a 1.00 inch bore size, which is allows for nice pedal modulation with the additional volume requirement of  your new rear disc brakes. It also has metric fittings, which will allow for an easy installation for the 87-93 setup. You will however need to use the 3-2 port MC adapter kit that we also carry. This will simplify your MC upgrade as your original OEM MC has 3 ports/brake lines going to it. Any newer, performance based MC will only have 2 ports on it. This also includes the MC from the 1994/1995 Mustang. You therefore need to make a provision for this and the 3-2 port adapter kit will work out nicely

1979-1986 Mustang

For owners of the 1979-1986 Mustang the easiest MC kit to use that is also appropriate for a rear disc brake upgrade is to use the Lincoln style MC which is desinged for rear disc brakes. This MC also has a 1.00-inch bore size. Just as important is the fact that this MC has SAE standard US threads. It accepts the SAE inverted flared fittings. This is the type that the pre 1987 Mustang uses. This will simplify your upgrade. We carry this MC in a kit form ready to install.

Modifying the Factory Proportioning Valve (PV)

You will need to modify the factory PV on all 1979-1993 Mustang rear disc brake upgrades to get the most out of your new rear disc brake installation. The prop valve is designed to distribute a balance amount of brake pressure to the front and rear brakes based on the specifics of the particular model and year vehicle. The particulars of the factory braking system along with the weight and front to rear balance or weight distribution  were all factors for the original PV front/rear brake pressure balance. You have now changed the rear brakes from drum to disc brakes and also will soon be installing your new front brakes you will need to change the original front to rear pressure balance or "bias" that the original factory PV provided.  The new disc brakes require more pressure and more fluid to work properly. This modification is easy to do. There is a kit which includes a new plug and instructions for making the changes available from Ford Racing. We carry this plug kit - the 2450 plug. Along with the 2450 install and modification you will also need to use a universal adjustable proporitiong valve. This adjustable PV will allow you to fine tune your rear brake pressure, allowing you to get the most out of your new rear disc brakes. The adjustable PV can conveniently be located at the passenger side firewall location for ease of installation and adjustment. There is a factory brake fitting which can be removed and the adjustable PV installed in its place. We carry a variety of adjustable PVs that will work out nicely for this.

More to come.........

For now please look in my Ebay store if you are in need of specific components such as front and rear emergency brake cables, front and rear brake hoses, brake line adapters, adjustable proportioning valves, proportioning valve plug kit, master cylinder kits including the 1993 Cobra MC, other year replacement e-brake cables, many Ford Racing parts and accessories and much more!

Thanks for looking.