I was wondering if there is a way to convert the stock rear drums on my '91 5.0 to disc brakes, and staying 4-lug. I'm not interested in spending the time and money on a 5-lug conversion right now. If it's even possible to convert it to 4-lug discs, I'd like to know, Thanks
I'm doing this also. Everyone will tell you to go to the mjbobbitt site. You can go the 93 Cobra/88 tbird coupe rear discs with the 4 lug stock axles, but you'll need a bracket that puts the calipers in the right spot. Those can be had from northcobras website. Those brackets run $140 and the cobra calipers can be had from most parts stores as rebuilts or knock offs for around $100 apiece. You'll need misc. parts like lines etc. but then you need a new master cylinder a proportioning valve etc......so it adds up no matter what you do. So my math adds up to about $500 or so.....
i scored a ssbc rear kit for cheap and went with it.its the same a s cobra/turbocoupe.shop around you will see lots of guys selling there stuff after they go 5-lug(theres a guy on here now selling his cobra stuff for 300)but you will need alot of other stuff like 3-2 adapther the a-plug and prop.valve so it isnt cheap. phil
There are kits out there you just have to look around. I believe that Turbo Coupes also had a 4 lug rear with discs that you can use. Also the Turbo Coupe rear has 3.55s with the stick shift and 3.73s with the auto if I remember correctly.
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” 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, http://www.svo73mm.cjb.net/. 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 http://forums.stangnet.com/showthread.php?p=6143048 for details and pictures.
See http://www.mustangcentral.net/tech/brake.html 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.
There are kits out there specifically for this. I used the SSBC (Stainless Steel Brakes Company) kit on my old '92 years ago and was very happy with it.
I plan on doing the same thing to my new '92 convertible as soon as I can. The SSBC site has the new kit listed at $850 I think but I found it for $650 at 50resto.com (not sure if it's still available at that price). I don't have the time or (close) resources to piece a kit together so I like the idea of a complete kit with new parts all designed to work together. I have a lot of respect for guys that figure out the parts they need from different cars and can piece together the kit themselves. So, two options are 1) buy a complete kit or 2) piece it together yourself. There are plenty of resources out there for both avenues...and you can do the work yourself.
My advice, and you can take it or leave it... sell the farm now (wheels etc) and live up to the fact you will eventually convert to 5 lug. I just sold my 4 lug wheels and 4 lug rear disc setup for the inevitable...5 lug setup. And lost a couple hundred in the end.
Save some cash in the long run and go to 5!
Just my .02 if you dont agree with me now... you will later