5 lug conversion questions...

stangboy

Founding Member
Aug 31, 1999
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New Orleans, LA
I'm planning to do the 5 lug conversion with the 13" Cobra front brakes. My question is do you have to get the SN95 master cylinder for the bigger discs up front? If yes, do you have to get the booster too or is the fox booster sufficient?

I'm pretty sure all that stuff is need if I do the rear dics too but thats not in the budget right now.
 
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I did the conversion on my 88 and kept the stock master cylinder. It works but you loose alot of braking power. I am going to put a proportioning valve in for the back brakes for burnouts at the strip. I want to be able to shut the back right off. Looking back, I wish I would have upgraded everything at the same time, I just know any better.
 
start reading here.... this will be your new bible.

87-93 Mustang 5.0 Brake upgrade pages. Improve your 60-0 times!

79-93 5 Lug Ford Fox Body Mustang Conversions:



1. What conversion to use
2. Which way to convert to 5 lug
3. 5 lug conversion options
4. Rear drum conversion
5. Converting 4lug rear disc to 5 lug
6. Sn95 rear disc brakes
7. North Racecars rear disc
8. Parts list

1. Which conversion to use?

I would suggest that you first decide which tires and wheels you want to run. 11"and smaller brakes fit under 15"+ wheels, 12" brakes require 16"+ wheels, and 13"+ brakes require a 17" or great diameter wheel. If you are going 5 lug, be sure to decide on the wheels before considering the brakes.

2. Which way to convert to 5 lug?
This will really depend on what you want for brakes and the wheels you want to use.

If you want to run all 4 of the same wheels with 9" wide rims, then you are going to want to keep the stock rear track width. You can do this with the Ranger axles basically. You have options from there with the Ranger axles:

1. rear drums from the ranger
2. flipped rear disc 11.375" from the Lincoln 85-91 Mark7
3. Cobra 11.65" rear disc with the BigMac or North Cobra brackets

If you are only going to run 8" wide OEM rims, then the extra offset in the rear from the longer SN95 axles (.75") will not hurt you. But if you go to 9" wide wheels, you will need more offset for the rears like the M179 Cobra R wheels (6.42" BS, 36mm offset).

Basically I would suggest to figure out the wheels you want to run first and then go from there with your decision. For the front, the best is the Sn95 parts with the '94-95 spindles to keep the stock track width. Again, if you are running 8" wide wheels, then the '96+ spindles with the extra 8mm will not hurt you.

Spare Tires

When converting from 4 to 5 lug wheels or from the 94+ GT/V6 brakes to the 13” units, you are going to have to address the spare tire for street use.

You can find 5 lug Ford spare tires with the 5 x 4.5” bolt pattern on many vehicles. Rangers, Explorers, Bronco II, Lincolns, Crown Victorias and the 94+ Mustangs to name a few. Most of the spare tires you will find will be 15” in size. This is the stock spare tire size on the 94+ Mustangs also with the GT and V6 package. So if you are upgrading to the GT/V6 brakes, you should not have a problem finding a spare.

Now when you upgrade to the 13” brakes, the cobras come with a special sized spare tire to fit the larger brake rotors. These are not easy to find and can be costly when you do find one.

There is another solution. Get a 15 or 16” spare from one of the many applications already listed. Now that spare will not clear the front 13” brakes, but will clear the rear brakes just fine. So if you get a flat on the rear, you can just change the tire with the spare. Now if you get a flat in the front tire, what you are going to have to do first is change the spare to the rear tire. Then take the rear tire and swap it with the front one. Keep in mind that this trick only works if you have the same sized wheels on all 4 corners of the car. If you do not, then plan to spend the money for the 94+ cobra spare.

3. 5 Lug Conversion Options:

This page is mostly geared towards the stock 4 lug wheels and stock '87-93 GT/LX wheels. Hence the "budget" name to the page. Here are some of your options for converting to 5 lug:

Cheap way:

-For the 79 v8, 82-86 Mustangs, and 87-93 4 cyls, you can use the 4cyl 83-88 Ranger rotors.
-For the front 87-93 v8 cars, use the rotors from a mid 80's Lincoln Continental, Lincoln Mark VII (85-91), or '84-'86 SVO. For the 79-86 and 87-93 4cyl cars, use the 83-92 4cyl Ranger front rotors. This will keep the cost down and allow you to keep the stock front brakes. You can buy the rotors for about $40-60 each. You an also purchase after market front rotors like the Power Slot brand in 5 lug. These cost about $99 each.

**Important note here! The SVO/Lincoln front rotors will NOT work with the Ford '98 & '99+ Cobra, Y2K Cobra R wheels, and '97+ GT 17" wheels. Most of the wheels will mount up ('98 cobra and the Bullitt wheels will not), but you will not be able to mount the center cap due to the larger dust cap on the rotor. To run these wheels, you need to convert over to the SN95 front brakes (this includes spindles, rotors, hubs and calipers). Alternatively you can use a wheel spacer, but it is not recommended. The Lincoln/SVO rotors will work for the' 95 Cobra R wheel, 16" SN95 Pony wheel, and '99+ 15" & 16" wheel since they have a different center design and cap. If the center of the wheel is recessed, the Lincoln/SVO dust rotor will most likely be to large for the center cap of the wheel.

-The 1995 Ford Cobra R wheel comes in two different offsets, 24 mm and 36 mm. The original Cobra R wheel, the R58, has a 24 mm backspacing which is good for all four corners of an SN-95 car. The R58 also fits well in front of a Fox body car that has the Cobra brake upgrade. But the rear of a Fox M2300-K car requires use a later model, the M179, which has 36 mm of backspacing, and therefore places the wheel 12 mm further inboard to clear the fender well. The R58 and M179 wheels are now discontinued by Ford! Keep this in mind with your conversions. I would suggest to keep the stock rear track to so you can run the aftermarket copies of the R58s on all 4 corners.


Sn95 Parts (94+ mustangs):

Here is the list of parts that you will need:

* '94-95 spindles from a V6, GT or Cobra. They are all the same. Left and Right side. These will keep the stock front track. You can use the '96+ newer units, but the track will increase 8mm per side.
* 2 hubs. These come in ABS and non-ABS units. Either one will work.
* 2 hub nuts to spindle
* 2 dust caps
* 4 spindle to caliper mounting bolts (same bolts on all 94-present mustangs)
* 0.330" tall spacer, 5/8" inside diameter , 1.5" outside diameter (or a stack of washers totaling 0.330"). This is needed to properly fasten the crown nut on the lower control arm ball joint (the fox ball joint is about 1/2 taller than the SN95s and you will run out of threads, pic). If you are buying new tubular A arms, get them with the SN95 ball joints. Here are pics of a homemade one: [pic 1] [pic 2]
* calipers and rotors -- see part 3.2 to help on this decision!
* If your car is lowered, plan on offset rack bushings or a bumpsteer kit with the '94-95 spindles, measure on the '96+ modular units.
* Keep in mind that master cylinder, 3-2 port conversion kit , and proportioning valve upgrades will also be needed if you got to rear disc!

Why upgrade to the SN95 spindles on a 79-93 Mustang? There are many benefits to do this. First, the bearings are sealed and separate from the rotors. This keep maintenance very easy since you don't have to pack bearings. Second, they are the basis for brake upgrades such as the Cobra 13" and Brembos. Third, they have better steering geometry creating more ackerman steering. This increases turn in. Lastly, if you want to run some of the OEM Ford 17" and 18" wheels, you will need to run these spindles. Wheels such as the '97+ 17" GT wheels (including the bullitt wheels), the '98-present Cobra wheels, and the Y2K Cobra R wheels.

4. Rear Drum Conversion:

To keep the stock rear wheel offset and drums, the '83-'92 Ranger/Bronco II Left (driver) side axle (29-5/32") from a 4cyl or 3.0L V-6 with the 7.5" rear end, or '86-'97 Aerostar RIGHT side axles (29-5/32") is what you want. They are the same rear axles, the center section is just on the opposite side when you compare the rear ends. The pumpkins are also off center unlike the Mustangs, so you will have to find two vehicles to pull axles from! You will need the drums from either of these vehicles also if you are staying with rear 9" drums. The 7.5 axle Rangers & Aerostars use 9" drums. These parts are direct 5 lug replacements for the stock 9" rear drums on the 79-93 Mustangs.

*Important: Don't get the axles and drums from a Ranger with the 4.0L engine, as they use 10" rear drums with a wider 8.8" axle (unless you want to convert to larger drums!). The 8.8 in the Explorer is 1" wider per side than the Ranger/Aerostars with the 7.5" axle.

Most of the larger mail order companies have kits that you can purchase, although they are overpriced! The front conversion using the SVO/Lincoln parts running $180-199 for the front 11" rotors (which you can buy for about $40-60 each) and the rear axles and drums for $180-199 (less than $50 from a Ranger or Aerostar).

If you are upgrading just the rear to 5 lug drums, you will not need to modify the PV.

5. Converting your 87-88 TC/93 Cobra/M2300C brakes to 5 lug:

There are no direct bolt on options for the rotors. The Sn95 units have a different height hat, so they will not work. You will have to get the rotors redrilled for the 5x4.5" bolt pattern. For the axles, if you are using the longer '87-88 TC or '93 Cobras, than you can use the '94-98 Mustang axles. If you are using the brackets to keep the stock length axles, then the Ranger/Aerostar axles . You may have better luck selling your setup with axles, brackets, calipers, rotors and softlines to someone wanting 4 lug rear disc brakes and buying a new setup like the SN95 , Baer or flipped Lincoln setup.

6. Sn95 Rear Brake swap for fox3 ('87-93) cars:

The '94-98 cars rear axle shafts are .75" longer than the stock axles on the '87-93 cars. Be sure you note this longer axle if you are running 9" wide wheels because you will need the wheels with the extra offset like the M179 Ford '95 Cobra Rs (6.45" 36mm) -- which are now discontinued! You can use the 8" wide wheels without issue, but if you want 9" wide wheels you need to convert the brakes to use the stock rear track with Ranger axle shafts!

The V6 cars use the 7.5" rear axle. So the axle housing and gears will be no good to the 8.8" rear end, but everything else will! The '94-98 GT and Cobras use the 8.8 rear end with a 3.27 gear in them stock. Most yards will only sell the complete rear axle assembly presently. So if you get the 8.8 unit, just bolt that in. It will be a direct swap except the brake line fittings to the chassis will need to be adapted. You can also use the stock drum brake hardlines with 2 adapters at the caliper softlines to convert.

Remember that the V6/GT/Cobra all use the same axles, calipers, and brake lines. The axle bracket, rotors and pads (same pads as the V6/GT, just thinner) are specific to the Cobra.

The '99-04 V6/GTs are even longer at about 1.4x", so you will NOT want to get the axle off a '99-04 car. Also the control arm bolts are larger, thus the UCAs and LCAs are not a direct bolt on - unless you install 94-98 bushings in them. You can use the brake hardware off the 99-04 cars, but you will need to use the 94-98 axle shafts in the 79-98 axle housing.

If you are going to get all the parts, here is what you will need:

* axles
* calipers - complete with pads, banjo bolts, mounting bolts, and brake line
* brake lines. This includes the soft lines with the axle mount and the hard lines. If you are buying new, get the 94-95 units
* rotors
* caliper bracket -- these are specific. so if you are going to use the Cobra rotors, you need the Cobra bracket. V6/GT rotors, get the V6/GT brackets.
* antimoan bracket
* caliper bracket to axle bolts and nuts.
* optional -- ABS sensors and wires if you are going to run ABS.

For the E-brake cables, the 87-92 cars will use the (2) FMS M-2809-A cables. The 93 model year cars will use the 93 Cobra cables (F3ZZ-2A635-A). You will also need an adjustable center cable; (1) FMS M-2810A

7. North RaceCars Rear disc SN95 conversion brackets (stock rear track length):

This is a special bracket that uses the 94+ Mustang rear calipers and rotors. What is special about the brackets is that you can use the stock 87-93 length axles, but in 5 lug! So if you have custom wheels, or converted to 5 lug with the Ranger/Aerostar or FMS conversion, you will not have problems with the offset. You can also run the same wheels on all 4 corners of your car. For 4 lug, you will have the re-drill the rear rotors to the 4 lug bolt pattern. Here are the basic parts you will need for the conversion:

Cobra Rear 11.65" rear rotors:
- North RaceCars Brackets - for the cobra rear rotors
-94-98 loaded Cobra calipers complete (with bracket and hardware)
-94-98 Cobra 11.65" vented rear rotors
-For the 87-92 cars, use the (2) FMS M-2809-A and (1) FMS M-2810-A cable
-For the 93, use the 93 cobra cables F3ZZ-2A635-A
-94-95 rear caliper hoses

94+ Mustang GT/V6 10.5" rear rotors:
- North RaceCars Brackets - for the GT/V6 rear rotors
-94-98 loaded Mustang calipers complete (with bracket and hardware)
-94-98 GT/V6 10.5" solid rear rotors
-For the 87-92 cars, use the (2) FMS M-2809-A and (1) FMS M-2810-A cable
-For the 93, use the 93 cobra cables F3ZZ-2A635-A
-94-95 rear caliper hoses

Other than that, fluids, a few miscellaneous fittings, caliper bolts, and address the stock master cylinder and proportioning valve.

Since there is a difference in the size of the rotor and hub, you need a spacer to center the rotor. Find a pipe that is 2.5" ID, 2.75" OD and about 3/8" tall to use. You can also get a spacer of those dimension made.

Links:
North RaceCars Brackets


8. Parts list for Sn95/M2300K and more:


Front w/94-98 Gt/V6 66m caliperss:
94-present Gt/V6 10.84" rotors (2)
94-98 GT/V6 calipers (2)
94-98 Gt/V6caliper brackets (2)
spindle to caliper bracket bolts (4): N805163-S190
1994+ spindles (2)
Hubs (2)
hub nut(2)
dust cap(2)
dust shields (2) : F4ZZ-2K005A , F4ZZ-2K004A
SS brake lines designed for conversion - or - SN95 brake lines with Adapter
Balljoint spacer or stack of 3 washers totaling .330" in height or press in Sn95 balljoints to the stock arms (MOOG brand)

Front w/'99+ GT/V6 twin piston PBRs:
94-04 Gt/V6 10.84" rotors (2)
'99-04+ GT/V6 PBR calipers (2)
'99-04 Gt/V6 PBR caliper brackets (2)
spindle to caliper bracket bolts (4): N805163-S190
1994-04 spindles (2) (94-95 spindles will need to be ground to fit this calipers)
Hubs (2)
hub nut(2)
dust cap(2)
dust shields (2) : F4ZZ-2K005A , F4ZZ-2K004A ($7.70 each)
SS brake lines designed for conversion - or - SN95 brake lines with Adapter
Balljoint spacer or stack of 3 washers totaling .330" in height or press in Sn95 balljoints to the stock arms (MOOG brand)

Front w/Cobra PBRs:
13" cobra rotors (2)
cobra PBR calipers (2)
cobra caliper brackets (2)
caliper pins (2)
spindle to caliper bracket bolts (4): N805163-S190
1994-04 spindles (2)
Hubs (2)
hub nut(2)
dust cap(2)
dust shields (2) : F4ZZ-2K005A , F4ZZ-2K004A ($7.70 each)
SS brake lines designed for conversion - or - SN95 brake lines with Adapter
Balljoint spacer or stack of 3 washers totaling .330" in height or press in Sn95 balljoints to the stock arms (MOOG brand)
Banjo/caliper bolts (2) 10mm x 1.0 thread

Front w/Brembo 4 pots or Wilwood 6 pots:
Brembo 4 piston Cobra R kit (includes rotors, calipers, bolts, SS brake lines, and pads) -- or -- Wilwood 6 pot Brake kit
spindle to caliper bracket bolts (4)
1994-95 spindles (2)
Hubs (2)
hub nut(2)
dust cap(2)
Balljoint spacer or stack of 3 washers totaling .330" in height

MC and PV (see my MC/PV Page):
(87-93 cars) '93 Cobra 1.00" master cylinder (or a 94-95 15/16" bore cobra unit for a softer pedal feel)
3-2 port adapter kit
FMS M2450 plug
adjustable proportioning valve



Rear w/sn95 cobra disc (Upgrade for GT/V6 94-present cars):
11.65" vented cobra rear rotors (2)
cobra axle brackets (2)
cobra caliper/anchor bracket or grind the stock ones to fit the thicker rotor (2)
cobra anti-moan brackets (2)
pads for 94-98 cobra (1 set)



Rear w/sn95 cobra disc (stock track for 79-93):
driver side Ranger axles or passenger side Aerostar axles (2)
11.65" vented cobra rear rotors (2)
sn95 calipers from 94-98 v6/gt/cobra (2)
soft brake lines (2)
pads for 94-98 cobra (1 set)
North RaceCar brackets (2)
FMS M2809A ebrake cables for 87-92 car (2) - or 93 Cobra cables for 1993 cars (2) F3ZZ-2A635-A
FMS M2810A center ebrake cable (1)
adapter from softline to hard lines (2)

Rear w/sn95 cobra disc (sn95 (94-98) track; .75"wider per side):
94-98 Mustang axles (2)
11.65" vented cobra rear rotors (2)
sn95 calipers from 94-98 v6/gt/cobra (2)
soft brake lines (2)
pads for 94-98 cobra (1 set)
94-98 Cobra axle brackets (2)
FMS M2809A ebrake cables for 87-92 car (2) - or 93 Cobra cables for 1993 cars (2) F3ZZ-2A635-A
FMS M2810A center ebrake cable (1)
adapter from softline to hard lines (2)

Rear w/sn95 GT/V6 disc (stock track for 79-93):
driver side Ranger axles or passenger side Aerostar axles (2)
94+ GT/V6 10.5" solid rear rotors (2)
sn95 calipers from 94-98 v6/gt/cobra (2)
soft brake lines (2)
pads for 94+ GT/V6 (1 set)
North RaceCar brackets (2)
FMS M2809A ebrake cables for 87-92 car (2) - or 93 Cobra cables for 1993 cars (2) F3ZZ-2A635-A
FMS M2810A center ebrake cable (1)
adapter from softline to hard lines (2)

Rear w/sn95 GT/V6 disc (sn95 (94-98) track; .75"wider per side):
94-98 Mustang axles (2)
94+ GT/V6 10.5" solid rear rotors (2)
sn95 calipers from 94-98 v6/gt/cobra (2)
soft brake lines (2)
pads for 94+ GT/V6 (1 set)
94-98 GT/V6 axle brackets (2)
FMS M2809A ebrake cables for 87-92 car (2) - or 93 Cobra cables for 1993 cars (2) F3ZZ-2A635-A
FMS M2810A center ebrake cable (1)
adapter from softline to hard lines (2)

Rear w/85-91 Lincoln Mark7 disc:
driver side ranger axles or passenger side aerostar axles (2)
SVO/Lincoln Mark 7 rotors, side specific (2)
rear calipers with caliper brackets (2)
soft brake lines (2)
pads for SVO/Mark7 calipers (1 set)
Lincoln axle to caliper brackets, flipped (2)
FMS M2809A ebrake cables for 87-92 car (2) - or 93 Cobra cables for 1993 cars (2) F3ZZ-2A635-A
FMS M2810A center ebrake cable (1)
adapter from softline to hard lines (2)

Misc:
4 more lug nuts or locking lug nuts
5 lug spare tire
gear lube
friction modifier
RTV gasket maker for rear differential cover
brake fluid
new C clips

Optional/may need:
94-98 v6 brake booster (for 79-93)
bumpsteer kit


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Matt90GT
 
I did the conversion on my 88 and kept the stock master cylinder. It works but you loose alot of braking power. I am going to put a proportioning valve in for the back brakes for burnouts at the strip. I want to be able to shut the back right off. Looking back, I wish I would have upgraded everything at the same time, I just know any better.


You want a line-lock for that. Not a proportioning valve