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The following is a description of an upgrade I did to the brakes on my 1986 Mustang GT. Here's a quick summary of the results:

• upgraded the rotors from 10" diameter to 11" diameter.

• upgraded the calipers from 60mm pistons to 73mm pistons.

• upgraded the master cylinder from 0.827" bore to 1.125" bore.

DISCLAIMER

The work described herein is merely a description of the work I performed on my own vehicle with my own 2 hands in my own garage with my own tools. I am not responsible for any work someone else does on their own vehicle. Enough of that. Now for the good stuff.

BACKGROUND

I bought this car new in 1986. It's a daily driver and I've put over 100,000 miles on it. I don't do roadracing, but in the past 2 years I've made a few trips to the drag track.

The '86 GT has 10" diameter rotors with 60mm brake calipers on the front and the 'Pinto' drum and shoe brakes on the back. While this setup is adequate for normal stopping, I can honestly say that in the 10+ years I've driven this car these brakes did not give me a lot of confidence in a panic-stop situation.

Ford apparently recognized that as well and for the '87- '93 GT's (excluding the '93 Cobra) they upgraded to 11" diameter rotors and 66mm brake calipers while the rear brakes remained unchanged (please note that when I say GT, I also mean 5 liter LX as well). These pieces provide the foundation for my upgrade. I could have spent the $1,100 or so on the Cobra Brake kit from Motorsport (M-2300-K) (plus new 5-lug wheels) but that would be way too much brake and cost for me. If I was hot and heavy into roadracing, then it would be a different story.

INSTRUCTIONS

There are none. I had to make up my own using, copying, and/or modifying the information contained in the references listed below. This stuff was and is invaluable. My thanks again to everyone who contributed info and advice.

PARTS

The following is a list of the parts I purchased. There are many sources for these parts both new and rebuilt. I shopped around.

1. Used spindles and 11" rotors from a 1993 Mustang LX 5.0L. $150 shipped.

The '86 spindles and rotors get pitched. The '87-'93 spindles bolt right in with one exception: the strut mounts are thinner than the ones on the '86 spindles. I could either buy new struts for an '87-'93 GT or bolt (2) 1/8" spacers in with my existing struts. I bought new struts since mine were still the original factory units.

2. Rebuilt 73mm loaded pair calipers from a 1986 Lincoln. $125 list, I paid less. RMC part # P143. According to the auto parts store, all the mid-'80s Lincolns use the same calipers. They had the same part number for all of them. These loaded pair calipers came with steel pistons (better than phenolic), semi-metallic pads, crush washers and caliper pins. The pins have hex heads, not the dopey Torx heads.

3. Steeda stainless steel caliper sleeves. $30/set Steeda part # 363-0114. These weren't necessary for the upgrade, I just wanted them.

4. Rebuilt master cylinder from a 1986 Lincoln. $32 list, I paid less. Wagner part # R105806. This is basically the SVO unit. It features a larger bore (1.125" vs 0.827") and steel pistons (again, better than the phenolic).

5. New flexible front brake lines for a 1987 Mustang GT. $24/each. Bendix part # 77795 & 77796. The flex lines from the '86 won't work with the new calipers. I pitched them with the rotors and spindles. These new lines are nice. Part of the line is metal and it bends away from the back of the tire towards the engine and then the rubber part connects from there to the hard line on the car.

6. New banjo bolts (also called caliper hose bolts) to fasten the new flex lines to the calipers. About $3/each. Perfect Parts part # CB-11B. These bolts are metric. The size is M10-1.50 X 24 for a Ford rear wheel drive car.

7. New brake cylinders for the rear brakes. $15/each. These were not necessary for the upgrade, but mine were still the originals and I wanted to put new ones on. I also bought an 'axle kit' which has all the little springs and clips and pins for drum and shoe brakes and replaced all that hardware too. ($8)

8. Miscellaneous things like wheel bearings, grease seals, grease, DOT 3 brake fluid (bought 2 qts, used 1), turning the rotors, etc. $60

9. New front struts, Monroe. $40/each. Again, these were not necessary for the upgrade, but mine were the original factory units. I just got simple stock replacements.

10. The primary outlet is the same size for the stock '86 master cylinder and the SVO unit, 9/16-18 SAE 45^ inverted flare. The secondary outlets are different. The stock '86 MC has a 1/2-20 fitting and the SVO MC has a 7/16-24 fitting. I bought a new 12" long piece of 3/8" steel brake line and the necessary adapters to attach that new line to the SVO MC and the stock proportioning valve. The secondary inlet size on the proportioning valve is also 7/16-24 (all above sizes are SAE with 45^ inverted flare ends). The cost was about $5.

INSTALLATION

Chasing down the parts was really the hard part of this project. Everything else is just basic wrenching.

I started by sucking the brake fluid out of the reservoirs making sure none landed on the paint. I used a syringe left over from our days with infants.

I raised the front end, put the car on floor jacks, and removed the wheels.

I started on the driver's side and removed the caliper pins and disconnected the flex line from the hard line. I bought a set of SAE flare nut wrenches from Sears. They work great (any excuse to buy tools). There's a slide clip that holds the flex line to a bracket mounted to the car. That slides off and the flex line is free. To avoid having brake fluid dripping all over, I used the syringe to suck out the hard line.

I then removed the old rotor, strut, and spindle. The tie-rod ends were replaced recently, so I left them alone. Before removing the strut, I placed a floorjack under the control arm to keep it and the spring in place.

Spindles:

The new spindles bolt right in. I torqued the strut-to-spindle bolts to 200 ft-lbs. I should note that the struts I bought were for '79 to '93 Mustangs, so they came with the above-mentioned 1/8" spacers.

I had a little problem with the dust shields. The bolt pattern is not the same between the '86 and the '93 spindles. These shields are not big metal pieces. They're made out of plastic and are just big enough to cover the grease seal. I was able to rotate them a bit and hog out and use two of the mounting holes. That's good enough until I can order correct ones from the dealer.

I put the rotors on and snugged up the nut. I put the wheel on, since it's a lot easier to turn the whole assembly that way, and torqued the nut to 20-25 ft-lbs with the wheel rotating. I then backed it off 1/2 turn and retorqued to 10-15 ft-lbs.

I removed the wheel and put the clip, cotter pin and cap on. Done.

I played the same game on the other side.

Calipers:

Before installing the calipers, I removed the rubber caliper sleeves and put the Steeda pieces in place. My bench vice helped a great deal. While I had them clamped, I installed the flex lines on the calipers. I slid a crush washer on the banjo bolt, then the flex line, then another crush washer. This assembly was installed on the caliper and torqued to 30-45 ft-lbs. I wanted to make sure I didn't snap the bolt since it's hollow. Also, since the new caliper sleeves are open at the ends, I made sure there was plenty of lithium grease in them before I put the caliper pins in to seal and lubricate them. I don't want road grime getting in there.

The rest was easy. The calipers dropped in place and the flex lines hooked to the hard lines without a problem.

Rears:

The rear cylinder replacement was no big deal. Everything was direct bolt in. I find it amazing that a system as complicated as drum and shoe brakes can yield such unremarkable performance. So much for my commentary.

Master Cylinder:

The SVO MC is quite a bit larger than the stock unit, but it bolts right in. Before mounting it I followed the advice of my references and the instructions and bench-bled the unit. This kit came with two plastic fittings and two pieces of hose to make it easier. I also tilted the unit up and down while pumping to burp any big air bubbles hiding in the bore.

IMPORTANT: Before I bolted the MC in, I extended the pushrod from the booster about 1-1/2 turns. Then the existing primary line and the new secondary line were connected and everything was ready to be bled. My bending job on the new line wasn't the greatest, but it works.

Bleeding the Brakes:

Again following the advice of my references, I started by bleeding the passenger rear first and then the drivers rear. I did these about three times and then moved to the front, all the while making sure I didn't drain the reservoir. I played the same game in the front, topped off the reservoir, and hit the road. Just for piece of mind, I first checked all the connections to make sure they were tight. I also checked to make sure the flex lines were not rubbing on the tires.

Brake Break-in:

I've heard of different ways to temper the brakes. Some people drive on the freeway with their foot on the brakes until they smoke, or cook them in a toaster oven for hours (my wife would have no sense of humor about that). I did the "drive fast and mash the brakes" thing on some freeway entrance ramps until they got good and hot and stinky (accelerate to 85, hard brake to 30, over and over). Then I parked it in the driveway and let it cool.

I checked for leaks again, but everything was good.

SUMMARY

What a difference. These brakes have a very confident feel, and they really haul the car down. I guess that should be no surprise since these calipers were made to stop a 5000 lb Lincoln. Stopping a 3500 lb Mustang is a piece of cake. I can't wait to take the first turnoff after a quarter mile 100+ mph run <grin>. This was worth a day of wrenching.

MISCELLANEOUS

Wheels:

I'm running the factory 15 X 7 10-hole phone dial wheels. These were the standard GT/LX wheel on the '85 and '86 Mustangs, and were the standard LX wheel from '87 through '93. I had heard that I might have clearance problems with the big calipers. I don't.

There are at least 2 styles of this wheel. The part number is located under the center cap by the lug nuts. The older style 10-holes (like mine) begin with E5 (for 1985 I believe), and the newer ones begin with E7 (1987). There is a physical difference between these two wheels on the backside (the color is slightly different as well). The inside diameter of the newer wheel is about 1/4" or so bigger. I happen to have 2 of the newer wheels for my snow tires.

There is a noticeable difference in the clearance with the bigger calipers between the two styles. Actually, it's the pads that would rub, not the caliper. I have about 1/8" clearance between the rim and the caliper (pads).

It's not a lot, but it works.

Brake Lines:

My original intention was to put stainless steel braided flex lines on the front. I purchased some mail order, but I didn't realize until after they arrived that they are not DOT legal (ie. off-road use only). After some discussions and knowing the way our legal system can work, I decided on the stock replacements listed above. I know that Steeda and some other places offer DOT-approved braided stainless lines, so I may pursue them at a later date.

REFERENCES

"Building the Perfect Pony", Scott Griffith

"Mustang Performance Handbook 2", William R. Mathis

"Low-Buck Disc Brake Upgrade" from "5.0 Mustang" magazine, June, 1996

The '5.0L Mailing List' and its members; Bill Rockefeller, Moderator