4 lug vs 5 lug

christessmer420

New Member
Aug 1, 2008
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my mustang is a 4 lug and i want to upgrage the rear brakes to disc brakes. there are alot more kits out there for 5 lug and im gettin new axle shafts soon so should i just go with the 5 lug?
 
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5 lug offers more rim selections. If your not looking for a high performance package you could just get a set off a V6 or GT 94-2004 Mustang along with the axles. If you get a GT rear end just make a entire rear end swap.
 
The only thing wrong with 4 lugs is that they just don't look right when you have a 5 spoke wheel. There are some exceptions, but not many.

Been there and done that! 4 lug and rear disk brakes! With success! :nice:

Do the 87-88 T-Bird Turbo Coupe rear end swap!

Auto trans 87-88 Tbird Turbo Coupes come with 3.73 gears and manual Turbo Coupes come with 3.55 gears. Cost is $125-$300 for the rear axle. Add another $100-$200 or so to complete the brake upgrade.

I choose 3.55 since I do more highway driving. Both ratios have 10 5/16" disk brakes with vented rotors as standard equipment.

It takes 2 guys the first day to get the old rear end out and the new one bolted in place. It takes 1 guy another whole day to do the brakes.

You will need a several sets of fittings, I recommend that you get them from Matt90GT's website, 87-93 Mustang 5.0 Brake upgrade pages. Improve your 60-0 times!. Read Matt's instructions thoroughly, everything you need to know about the brakes is all there. You need to be patient and follow all the internal links, and there are many of them. You will need 2 fittings in the rear to adapt your old brake tubing to the TC disk brakes. The fittings go between the steel tube and the caliper brake hose. You will need another set of fittings to make a 2 port to 3 port adapter. To make life simpler, just buy the kits from Matt. You could piece them together, but it's not worth the time unless you work at an auto parts store with all the fittings ever made.

You will need to drill the quad shock mounting holes 2” below the holes drilled for the Turbo Coupe mounting points. The bolts are metric, so don’t loose them or the nuts. A 15/32” drill should be about the right size unless you have access to metric sized drill bits. Going without quad shocks is not an option unless you have aftermarket parts to soak up the wheel hop.

You will need a proportioning valve, Summit has one for $40 + shipping.
You will need a kit (FMS makes the part) to gut the stock proportioning valve, Summit also has that, about $10.


You will need a new master cylinder, see Matt's site and make you choice. I used a 94-95 Mustang master cylinder. Note that rebuilt 94-95 Mustang master cylinders do not come with a reservoir. That means a trip to the junkyard and some more money spent.

Your brake pedal may be very hard and almost impossible to lock up the brakes. I had to replace the front calipers with 73 mm calipers from a 91 Lincoln Mark 7 to get the braking performance up to par.

Bleeding the brakes will require 2 people and some coordinated effort. I don’t recommend using you wife or girlfriend to pump the pedal – they get offended when you yell at them. I used a homemade power brake bleeder constructed from a garden sprayer and some fittings from Home Depot. It cost about $25 and was worth every penny. See how hard is it to bleed brakes? - Mustang Forums at StangNet for details and pictures.

See Mustang Central.net FMS M2300K Brake Install for help with the emergency brake. The red words link to some very useful photos on how to modify the handle. The stock setup tends to lock up and not release properly.
All in all I have been very pleased with the results.
Identifying a Turbo Coupe rear axle:
1.) Measure the rotors - a TC disk brake uses 10 5/16" vented rotors.
2.) Measure the length of the quad shock mount arm and compare it to the mount on your existing stock axle. The TC quad shock mount arm is about 8" long if I remember correctly.
3.) Measure the distance between the axle flanges and compare it to stock. The TC rear axle assembly is 3/4" wider per side, or 1 1/2" wider for both sides.
 
I just swapped the rear with some 96 axles and rear disc when I did my 373 install. was pretty easy. but the tc swap is a great option as well. just a real pain in the arse to install an entire rear end when you are lying on your back. if you have access to a lift and a tranny jack then you'd be better off. good luck
 
ok thanks to your guys help i got it all figured out now. im keepin the axle housing from my 92 GT, im gettin a 31 spline trac lok differential with 3.73 gears from a 2000 explorer, rear disc brakes from a 88 tbird and a caliper bracket from North RaceCars so i can go with the ford racing 31 spline mustang axle shafts. thanks!

old_blue
im a farmer, we have a lift, trans jack, chain fall, etc....all the good stuff needed to rebuild my car.