Turbo Coupe rear end in a Fox? Educate me.

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There are no mods to do... it fits. I think the 93 Cobra uses the same 8.8 which is a little wider (3/4" per side). You'll need different offset wheels or chances are, you'll get some rubbing (no the good kind of rubbing lol)...

The automatic TC had 3:73 gears, LS, and disc brakes.

astronut1885 said:

Hey guys. I was reading in 5.0 Mustang+ Super Ford today and I noticed in an article that a guy put a Thunderbird Turbocoupe rear end in his 89 LX. I would like to know whatever there is to know about this, as I want gears and a rear disc setup would be an added bonus. What would it take in terms of hardware, modifications, etc. to put a turbocoupe rear in my 87 GT? Any info provided will be appreciated. Thanks Guys!

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Been there and done that! With success!

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.

Auto trans Turbo Coupes come with 3.73 gears and manual Turbo Coupes come with 3.55 gears. I choose 3.55 since I do more highway driving.

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 8 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.

All in all I have been very pleased with the results.

As of this date I am still working on getting the emergency brake to work without sticking, but the fix is in the works...

Could you just use the proportioning valve from the turbocoupe?

Boss 351 said:

Could you just use the proportioning valve from the turbocoupe?

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No way to adjust it for the different weight/weight distribution/braking performance between the Turbo Coupe and the Mustang. It would be too easy to get the rear brakes to lock up before the front brakes did. That might just mess up all you hard work and maybe your fuzzy little body too...

A proportioning valve from a 93 Cobra would work, but good luck finding one cheaper than $40 price for the Wildwood unit

Figure $35-40 for remaufactured or used MC, or $80-90 for new, $50 for the fittings and MC adapter, $10 for the PV plug, $50 for the adj. PV shipped, $50 for ebrake cables, so figure about $200-250 for the extra parts plus the rear end. If you just want it for the gears, then just use the housing & gears and swap your drum brakes and axles to that housing. Then you could maybe sell the disc brake parts and axles. I got a bare TC housing - no calipers or rotors- for $60, so it was a good deal to build my 5 lug conversion on it and swap it over... I basically got the gears for $20 since I later sold my old 2.73 gear 8.8 for $40. But it may not be worth the effort to you.

The main advantage of the TC is you get 4 lug disc brakes....and the gears are basically a bonus. $350-400 for a rear disc conversion is a pretty good deal.

Thomas

astronut1885 said:

I have pony rims on the car. I was reading on a site that had alot of info, but it confused the hell out of me. If I were to put in a TC rear, do I have to upgrade my booster and master cylinder? It looked like that on the other site, and it also mentioned something about modding the proportional valve and stuff. I have no problem putting line adapters in the rear, but if I have to rip apart my whole damned brake system, it may not be worth it to do this and not just install gears in the axle I have. I really don't care about rear disc, my car stops well enough, but I want gears really bad.

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FYI, I just did this on my car, worked very well. I put on the 3.73 rear. No worried about tire rubbing with a stock mustang tire, won't happen.

On a side note, I didn't feel like dicking around with the disc conversion, and didn't have the extra cash, and I just wanted a cheap way to get gears, so here is what I did.

1. Get the turbo coupe rear, pull your old rear from the mustang, and lay both rears side by side.

2. be sure there is no gear oil in either end, then pull the lid off the front of both of them.

3. Pull the clips off of the axles on both rears, slide both axles out.

4. Yank all of the rear disc crap off the turbo coupe rear. You will now see some brackets welded to the axle tube (not the quad shock ones) grab a big ****ing hammer (bfh) and wack off those "anti groan brackets"

5. Now bolt on the drum backing plate from the old mustang rear

6. Slide in the mustang 8.8 axle shafts, and c-clip them in.

7. Next you will need to install the brake line off of the mustang rear. In order to make this fit, I had to drill a notch in the side of the quad shock mounting bracket, no biggie. You will see what I mean. this gives you that extra little bit of room that you will need to screw the mustang brake line into the wheel cylinder.

8. Your set. Just install the rear, redo your drum brakes, and you now have 3.73 gears intalled for $100 or so!!!