Hey guys I’ve got a 88 mustang convertible with 93 cobra rear discs stock calipers up front and a 93 cobra mc. The brakes seam okay the first 1/2 of the pedal but then get unbearably hard to press after that and not much change in braking power, I’m wondering what I can do to help this? Maybe svo front calipers and svo mc? I’d really just like it to stop better than it does now
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.
Other small parts needed to complete the job...
Brake line Adapter fittings for rear brake line
3 line to 2 line brake fitting kit
Proportioning valve, Wildwood 260-8419 Summit or Jegs
Kit to gut the stock proportioning valve Ford Racing M-2450-A Summit or Jegs
Emergency brake cable parts: Summit or Jegs or Late Model Restoration
79-92 Mustangs use: M-2809-A* Parking Brake Cable (need 2)
93 Mustangs: use 93 Cobra Ebrake cables.
All years use: M-2810-A* Parking Brake Cable (short cable that attaches to the parking brake handle)
Yea the car had the 3-2 already done when I got it and the brake cables from lmr, I’m running the stock booster but I guess I’ll try the 73mm calipers. As you the proporting valve is that just for brake bias front to rear?
Yes, 73mm calipers just bolt up without modification but you will need the pads for them for a perfect fit.
The proportioning valve helps to get the balance correct so that the rear wheels don't lock up before the front wheels. If they do lock up before the front wheels, it makes the car hard to stop in a straight line. The rear end tends to come around or it tends to steer the car.
There's no reason to change calipers. That brake setup has been done a million times before with good results. It's basically a factory 1993 Cobra setup minus the booster. The 1" bore MC is ideal for the 60mm calipers, and 45mm cobra rear calipers. The setup us typically run with the 205mm booster, and not the stock fox booster, however many guys still run it with the stock booster with success.
WHat I would be checking is is there is a mechanical issue with the brakes. Do all the caliper pistons move freely? Are all the slide pins free? Perform some hard stops and use a cheap Harbor freight infrared thermometer to check the rotor temps and see if one is cold (one frozen piston will create a hard pedal condition). How do the rotors look? Do they all look the same in terms of condition, or does one look a little different with some score marks or heat spots? Rebleed all 4 brakes and make sure fluid flow is approximately equal and flows freely. I'd do all this before firing the parts cannon at it.
The 73mm calipers are almost 50% larger in terms of piston surface area than the 60mm units. When it comes to brake systems, that's huge without changing the MC and will result in a softer pedal, and longer stroke.
A better solution, if you don't want to change the booster, is the 94-95 cobra 15/16" MC which is about 15% less surface area than the 1" bore MC which will soften the pedal slightly and provide a slightly longer stroke. However, i'd check the entire system over thoroughly first.