Brakes 3-2 port brake conversion using SN95 fitting

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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I’ve often referenced this method, but never had pics. Until now.

When converting to rear disk, or aftermarket disk brakes, one needs to change the MC from the factory 3-port MC to a 2-port variety. Max Motorsports sells a kit for this, but there is another method, that is somewhat cleaner in nature, although not necessarily cheaper

If you are ever in the boneyard, look for a 94-04 Mustang WITHOUT ABS. This is the combo valve you want to seek out. It will look like this, with a unique fitting at the rear. If you notice, the combo valve looks like the Fox valve, but it's not exactly the same in terms of port sizes. But, the fitting at the rear is what you want. Take that fitting off.

This valve is off a 2003-2004 Mustang GT without ABS/TC. The big hex fitting on the left side is what you are looking for. If at a junkyard, this is all you need to take.
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I think you can see where I am going with this. At the rear of the stock Fox valve, is a fitting similar tot he front that is merely capping off the rear.

This is the 87-93 valve. Fitting at left is what you want to remove
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Remove that cap, and inside is a spring and a shuttle valve. The spring may come out, so you want to make sure this gets reinstalled as it keeps the shuttle valve in position

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Here's the fox PV with the SN95 fitting installed. Use a little light O-ring lube, or brake fluid to lube the o-ring and put in place. Do not use petroleum based lubes as it will swell the o-ring
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An Eaton/Weatherhead 7936 fitting can be purchased to adapt down to a inverted flare type line. I believe I bought a 2-foot long, preformed piece of line from NAPA and just bent it to fit from the rear of the PV over to the driver's brake soft line. Came out rather clean and OEM looking.
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But anyway, the key is finding the combo valve off a non-ABS SN95. Once you have that, you can do this much cleaner 3-2 conversion for maybe $10 in parts.


Of course, you'll want to remove the fitting up front and gut the PV by removing the proportioning spring. Then install the blank block off plug. Ford Racing M-2540-A (since obsolete, but there are aftermarket plugs available
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Plugs available here

 
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Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
36,522
12,470
224
Massachusetts
If you don't want to make your own line, classic tube will sell just the single line you need.

94-95 Mustang non-ABS front driver's side line. Part number MU3070A-SC. Was about $45 plus shipping in Stainless.

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Here's is the final install. The two bottom lines are existing. The combo valve in this photo is a stock 87-93 valve. All we are doing is removing the rear fitting to install the Sn95 non-ABS fitting that goes in this location. The SN95 line is just a nice clean way to get a premade line to finish it all off. Sorry that the clutch cable was in the way.

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KRUISR

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I did something very close to this when I did my 4 wheel disc conversion. I took the complete MC and prop valve still connected to each other (from an '01 non-ABS car), I cut the stock SN lines approximately 4" down from the fittings and took the complete driver front line (from prop valve to flex hose connection). The lines for the passenger brake line and rear line were only taken to get the fittings. I then cut my stock fox lines as close to my fittings as possible, put new fittings on and re-flared tubes. Then the stock lines connected to new prop valve.

I used the complete MC and prop valve because I figured the combination operated dual piston calipers in the front and discs in the rear already so the balance should be good. I did not open up or gut the SN prop valve.

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This is pic just after installed. Booster is used, from a 94/95 V6. MC and prop valve were installed but passenger and rear fittings are not yet attached. I think I bent the lines between the MC and prop valve a bit by hand to have them fit tighter to shock tower. Driver front line is heading forward off the prop valve (just line SN's do - I used the SN line, so it fit best this way). No clearance issues running this way - in case anyone is wondering.

Just as information... the NON-ABS prop valve is used because non-ABS SN cars use a single brake line to the rear (like the Foxes do). That way, an aftermarket prop valve on passenger firewall is not needed. ABS cars have a line to each wheel from ABS pump.
 
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