Brake Upgrade For 89 Gt Keeping 4 Lug

Discussion in 'Fox 5.0 Mustang Tech' started by plork66, Jan 21, 2014.

  1. Dammit...i need to drink my coffee first before posting. Your second question made me think of the ranger axles.

    Yes, you are correct. Ignore my post.

    You can use the atock axles if you use aftermarket caliper brackets. If you use the OEM ford brackets, you need to track down the correct 4-lug axles. There may be aftermarket options as these are the same axles as the 1993 cobra. In fact, 87-88 TC brakes are the same as the 1993 cobra.
  2. Don't waste your time or money on the 73mm front calipers.

    They do nothing but cause pedal feel headaches and a couple of millimeters in piston size literally means nothing.
    There is a reason quality brake companies goto 2+ pistons, it's so the pressure is spread out much wider on the larger rotors.

    BTW, i used 73mm calipers.

    Sounds like a low mileage car, i can appreciate that. But nobody is ever going to look at it and say "those massive modern brakes and wheels devalue the car".
    And it's not like you can't easily put it back to stock, although you won't.

    Do cobra/bullit fronts, fox width cobra or v6 rears and get yourself some nice ford wheels in 5 lug.
    You won't regret it.
    Mustang5L5 likes this.

  3. Ok. So for a stock fox length 4 lug disc brake I would need:

    Turbo coupe calipers and rotors
    North racecars stock length caliper brackets
    Brake pads for a Turbo coupe
  4. Also, booster and master cylinder and related hardware to connect. You'd want a 1993 cobra booster and MC since the brake setup is identical to what came on 1993 cobra.

    You'll also need to address the e-brake
  5. would the 94-95 gt booster and master cylinder work as well? These are much easier to find than the cobra stuff... This is just a daily driven car, not a drag or auto-x car.
  6. Booster yes. The thread pitch is metric, so make sure you get the 4 booster nuts as well. 1 stud is offset differently, so you will need to slot the firewall slightly to make it fit. Not a huge deal. I personally user a 94-95 GT booster in my car.

    MC is a different story. The 94-95 GT MC is 1/16" bigger in diameter than the bore of the 1993 cobra MC. Doesn't sound like much, but that would have an impact on pedal feel. You can try it, but you might find the pedal a bit on the stiff side requiring a tad more leg effort. There is a cost difference as a used 94-95 MC is cheap - $25 or so, while you more than likely need to drop $100 on a Cobra MC new. But in terms of what MC is more ideal for the TC rear disks (with stock 60mm front calipers), it is the 1993 Cobra MC.

    I have personal experience in swapping in a slightly larger MC than I should have with my car. that 1/16" does make a huge difference in feel.
  7. My car was briefly cobra discs in the rear and stock front brakes.

    I used the 93 cobra MC without the booster.
    Kept it the same when i went to bullit fronts.
  8. I wouldn't change the booster if I were you. It's a PITA and largely if not totally unnecessary.
  9. I agree. My old original booster finally bit the dust so I recently had to change it. What a PITA!! I went with a stock booster again and it works just fine with my 4 lug TBird disk settup.
  10. My two cents worth drawn from having a 5.0 Mustang that I put a TC disk brake rear axle in and used as a daily driver:
    94-95 Mustang Master Cylinder
    Stock 5.0 power brake booster
    73 MM front calipers from a 91 Lincoln Mark 7 (two calipers) local auto parts store
    Proportioning valve, Wildwood 260-8419 Summit or Jegs
    Kit to gut the stock proportioning valve Ford Racing M-2450-A Summit or Jegs.

    The result was great brakes for a street driven car. It felt like endless brakes, smooth, not touchy or too much pedal pressure. This is the setup that should have been standard equipment on 5.0 Mustangs from the factory.

    If you really wanted to go all out with this combo, add some stainless steel brake lines and, different front pads. If you do auto cross or light duty road race events, add some air ducting to blow cold air on the front rotors and calipers to keep them cool.
    Onefine88 likes this.
  11. I disagree on not changing the booster. I left my original booster in (partially in fear of how bad of a job it was) and did not like the pedal feel at all when i did my cobra brakes.

    Finally, i changes the booster and it was a major improvement. The job wasn't that bad either. Only took 2 hours and didn't need to bash a fender in
  12. So the booster seems debatable. Seems harmless to just leave it stock and test out how it works. If it's not up to par then you can invest the time and $ into upgrading it to get the correct pedal feel.
  13. That's pretty much how I did it. Try it out and see if you like the feel. If you think you need more assist...swap it out later.
  14. @Mustang5L5
    What size caliper pistons did you have? As you have pointed out many times, there is a best ratio of master cylinder piston size to caliper piston size.

    My setup was with the 73 MM front calipers & 1 1/16" master cylinder. Yours may have been very different.
    #34 jrichker, Feb 18, 2014
    Last edited: Feb 18, 2014
  15. Basically a Cobra M2300K kit. Cobra front and rear brakes. I swapped everything over like factory except for the booster hoping I could get away with it. Unfortunately, I could not and needed to swap in the booster.

    The brake setup here in question is pretty much a 1993 Cobra setup, which is why i usually push for replicating what the design engineers at ford used and use the 1" cobra MC and booster. I realize the booster swap is a tough one, but just urge people to not overlook a key component in the brake system. If you have legs like a bull, you might be fine, but if one was putting a car together for their 100 pound wife, then perhaps they might want to keep this in mind
  16. The 73 MM calipers have a different area/volume from the Cobra 60 MM single piston calipers. That's why the stock booster & 94-95 Mustang Master cylinder seem to work so well together.

    See for more on the brake combinations.
    #36 jrichker, Feb 20, 2014
    Last edited: Feb 20, 2014
  17. Correct, but that is also a non-stock brake setup. 73mm calipers ands rear drums never came OEM on any ford vehicle as a complete package. So you really do have to mix and match a bit there to get a good feel to the braking.

    A little bit more critical thinking required there, which is hard to explain when you get repeated brake upgrade posts from people who don't have the understanding of how brake systems work. That's why i try to push people towards what Ford did OEM. It's much more simple to understand, and explain that was vs the hybrid setups that some (myself included) run.
  18. Somewhere in the conversation, the Turbo Coupe rear disk brakes got left out. My apologies, that makes a big difference.
  19. image.jpg image.jpg image.jpg Forgot I said I'd report back. I installed the maximum Motorsports 4 lug upgrade and man, what a huge difference. Ss brake lines front and rear, hawk pads and drums, and steel caliper sleeves. Also replaced both leaky wheel cylinders and hardware on the drums. Stops 10x better now. Also changed the struts shocks and lower control arms to hotchkis. My fox actually handles decently! I recommend the 4 lug upgrade highly if anyone is staying 4 lug.

    Braking is even, stops straight, stops sooner. Overall just better than what it was.
  20. How much was that kit??