Master Cylinder Adapter kits, 3-2 Port kits for the 87-93 Mustangs (excluding 93 Cobra):

*** scroll to bottom of page to order ***

The stock master cylinders on the 87-93 Mustangs are marginal with just the install of larger front 73 calipers, and cannot be used if you install rear disc. You have to swap out to a newer 2 port 4 wheel disc unit from the newer Mustangs! The small 21mm bore size (about ~7/8") is to small for use with anything but the stock brakes. Even the 94+ Cobras use the smallest bore on a 4 wheel disc car which is 15/16"!  There is also the problem of not getting equal pressure to both front tires that the 3 port design is really to blame.  This is also solved with a 2 port MC design and will keep your front tires with the same brake pressure (preventing prematurely locking up one front tire under hard use),

There are 5 common MC upgrades out there for the Mustangs: the Lincoln/SVO unit, the 85 TownCar, the '94-98 GT unit, the '93 Cobra unit and the '94-95 Cobra units. Each is a 2 port MC, so a conversion will be needed but they are all different bore sizes. Which one is the correct unit for you? Depends on the car and the brake system.  The 79-86 mustangs have SAE threads on the master cylinders and the 87+ all use metric threads.  The Lincoln/SVO unit should only be used if you are using the 73mm front calipers and the lincoln or caddy rear disc!  The 85 Town car is a good unit for the 79-86 cars since it also uses SAE threads and has a 1" bore size. For the 93 Cobra and 94+ vacuum boosted master cylinders, it will depend on the calipers and engine you have in the car as to which one is correct.  The larger the bore size, the stiffer the pedal will be.  

The adapter kits that I am selling here is compatible to replace the stock master cylinder in the '87-93s to use the 93 Cobra 1" bore unit, the '94-98 V6/GT 1 1/16" bore unit or '94-98 15/16" bore Cobra units with specific kits ! These kits are a direct bolt in for the master cylinder that you are using! There are no flaring of the lines, just gentle bending of a few lines! Everything installs under the proportioning valve for a clean, sanitary look unlike other kits on the market.

Here is a basic drawing of how the kits work:


Since you cannot just bolt in a new master cylinder to the 87-93 cars, you have to first convert the 3 port to a 2 port design and secondly adapt any fittings for the different thread sizes on the master cylinders!

Here are the details of what master cylinders these kits works with:

Using '93 Cobra, '94+ v6/Cobra/GT master cylinders for rear disc conversions:

The 87-93 mustang master cylinders were a 21mm, 3 port design and will create a very spongy pedal. To run rear disc with these cars, you have to install a new, larger bore 2 port 4 wheel disc master cylinder. Since the front brake lines are both screwed into the stock master cylinder, you need a way to convert them to use the new 2 port master cylinder! This kit will allow you to do this with the '93 cobra, and '94+ master cylinders including the V6, GT and Cobra units!

These kits will convert your 3 port master cylinder setup to a 2 port setup to run larger calipers and rear disc with the newer mustang master cylinders! Email me with any questions! This is a great, clean way to convert over at the right price! Each kit comes complete with instructions on how to install it! Compare the the features and prices to other kits on the market, and you will be back to order!

No Cut, No flare Conversion kits:

'94-98 V6/GT & 93 Cobra Kit   -- for use with the '94-98 V6/GT 1 1/16" bore vacuum boosted units and 93 Cobra 1" bore master cylinders. Best all around value for price, size and pedal feel with rear disc or drums and most all front calipers! Use the 93 Cobra for a softer pedal feel when running an aftermarket cam rather than the 94-98 GT/V6 unit

[PDF Installation Instructions ]

'94-95 Cobra Kit  -- for use with the '94-98 15/16" bore master cylinder

[Installation Instructions ]

'99+ V6 Kit  -- for use with the 1.000" & 1.006" '99+ v6 master cylinders. These have different port threads than the previous '94-98 units and requires an extra fitting. Also you will need to convert over the wiring harness to the '99+ plug as it is different than the stock 87-93 fox body or reuse the stock low fluid sensor. 

[Installation Instructions ]

'94+ GT/V6 MC Conversion fittings -- For use on the 94+ GT/V6 cars with Vaccum boosters ONLY to use the '94-95 Cobra Master cylinder.  Direct bolt in!  No cutting, no flaring!

Keep in mind that due to all the differences that can be had with the brakes and vacuum of the motor, you may also need a larger brake booster to get an acceptable pedal feel.  You can get these from the 94+ vacuum boosted mustangs to increase the amount of boost.  

---

The stock proportioning valve will need to be modified if you go to rear disc or to install an adjustable proportioning valve. You will need the FMS part: M-2450-A and an adjustable proportioning valve to complete the modification. The stock PV is housed in the combination block under the MC towards the front of the car.  The rear of the combination block housed the shuttle valve or pressure differential valve.  Do not touch this shuttle valve assembly in the combination block.

Why do you need to modify the proportioning valve? Because it is designed for the specific car and brakes that come with it off the assembly line. So if you change to different size brakes, you will need to change the front to rear bias via the proportioning valve. If you do not, then you will not get the most braking capability out of the car. Worst case scenario, you have too much rear bias and the car spins around when the brakes are applied. Not good on a rainy night!  Why not use a Sn95 unit?  First off there is two different styles on the 94+ Mustangs.  The non-ABS cars have a unit with a factory 3rd port out the back of the valve.  You could use this housing unit to convert to a 2 port MC, but you have to get the brake line nut off the 3rd brake line.  You will not find that nut at any parts store.  The ABS equipped mustangs do not have this 3rd port and are mounted differently in the car.  With either unit, the bias is built for the newer Sn95 cars.  Thus the bias on these units is just as wrong as your stock unit for use with rear disc.  You need to set the bias properly for your car which means you have to install an adjustable valve after defeating/gutting the stock PV unit.  

Okay, so how do you "gut" this proportioning valve? You use a 13/16 wrench and take the front cap off of it. Be careful as once it is loosened, the spring will shoot it out! Then remove the spring, the spring seat and rod and discard. You may need some needle nose pliers to remove the rod from the valve. Do NOT remove the rear spring and rod from the rear of the valve. Transfer the rubber O-ring from the stock end cap to the FMS M2450A unit and install the FMS plug.

Once you are done modifying the stock valve, you need to install an adjustable unit. There are two kinds of adjustable units: knob style and lever style. The lever style is more designed for an in-car application so that you can adjust the bias as the tires and brakes wear down in a race. You want the knob style. To install it, remove the coupler along the passenger side firewall and replace that with the valve. [pic]

When you bleed the brakes, adjust the valve all the way in for the maximum rear pressure. Once done, adjust the valve all the way out, and then in 4 full turns for your initial setting. Adjust in 1 turn increments from there and then half turn increments to fine tune. You will feel the braking and the pedal differ as the bias is changed.

PV parts to purchase:

FMS M-2450-a Plug - Get from ANY FMS/FRPP dealer or places like Summit Racing

---

Others parts available:

*Modified Ebrake handles to defeat the self adjusting mechanism.  Modified like the M2300K kit instructions. A must have when using the rear disc brakes conversions.  (FMS M-2810-A cable is required in addition)   Done on a core/exchange basis

*Rear brake line adapters for use when using stock 87-93 drum brake hard lines and connecting the SN95 or TurboCoupe softlines.

*Fox3 to SN95 front passenger brake line fitting. Allows you to run the SN95 front brakes lines on a Fox3 car.

 

Click Here to Order

Payment methods accepted: PayPal



Info, questions and support, Email me: mjbobbitt@yahoo.com