Brakes The Ultimate 4-lug/5-lug Brake Conversion/upgrade Thread

[AeroCoupe]

You do not need the entire rear end. The axles out (meaning the axles and all the braking components) are the same between the V8 and V6 cars. So you can get the whole system off of a V6 car and install the axles and all the brake components into the Fox 8.8 housing. So you probably need some more information with regards to the 8.8 rear ends in these cars which is 87-98 8.8 housings are all the same. Where they differ is in the axle lengths and this is the 94-98 axles are roughly 0.75" longer per side and this was to make room for the ABS exciter ring that is pressed onto the axle shaft up by the flange.

Do not let the additional length of the axles worry you as there are all kinds of wheels with the correct offsets for this swap. You can run the Fox length axles but you will need a different axle to caliper bracket which will adds to the cost of the project.

To get the ebrakes to work you will need to modify the ebrake handle or install one from a 93 car or move up to a 94/95 handle. You can Google this. My car is a 93 so I did not have to make the modification.

 

[gkomo]

To get the ebrakes to work you will need to modify the ebrake handle or install one from a 93 car or move up to a 94/95 handle. You can Google this. My car is a 93 so I did not have to make the modification.

Mmmm, maybe this is what i'm missing as my e-brake is basically worthless at the moment. Currently running my stock 1990 e-brake handle/assembly with the SN95 rear end.

Just FYI, i run the entire rear end out of a SN95 and besides the e-brake the only issue i'm currently aware of is tire rubbing due to the wider track. Fenders are rolled but kind of jankily so i need to roll them more and more evenly.

 

[AeroCoupe]

View: https://youtu.be/d0nUueQxR64?feature=shared

 

[Mustang5L5]

I've seen mentions of the sn95 rear end(94-95 i believe) and that there are two types when it comes to the brake line/hardline/softline, and that one is much easier to swap to a fox body. Does anyone have info on this, specs, pics of differences ?

To answer this question. 94-95 Mustang axles have the brake lines mounted to the axle similar to the fox. It's a 3-channel ABS brake system with a single line to the rear like the fix cars.

96-98 went to 4-channel ABS and routed the brakes lines on the body so the axle is free of any lines. That means if you were to swap in an entire 96-98 axle, you need to buy and add lines.

 

[jaygee15]

I don't personally, recommend this route. Do the conversion to a Fox length axle housing. An SN95 axle on a Fox creates more issues than it solves IMO.


For the brakes:

Mustang Rear Disk Brake Caliper Adapter Brackets For 94-04 GT/V6 Calipers (79-93)

Check out these rear brake adapter brackets for your 79-93 Mustang Foxbody! Install 94-04 Gt/V6 Calipers

lmr.com

You will also need to order a set of axles.

I'd also choose this time to upgrade to a 31-spline F-150 Trac-Lok, but that's just me.

Can you elaborate what issues it creates? Will defintely be upgrading to 31 spline when I do the swap.

You do not need the entire rear end. The axles out (meaning the axles and all the braking components) are the same between the V8 and V6 cars. So you can get the whole system off of a V6 car and install the axles and all the brake components into the Fox 8.8 housing. So you probably need some more information with regards to the 8.8 rear ends in these cars which is 87-98 8.8 housings are all the same. Where they differ is in the axle lengths and this is the 94-98 axles are roughly 0.75" longer per side and this was to make room for the ABS exciter ring that is pressed onto the axle shaft up by the flange.

Do not let the additional length of the axles worry you as there are all kinds of wheels with the correct offsets for this swap. You can run the Fox length axles but you will need a different axle to caliper bracket which will adds to the cost of the project.

To get the ebrakes to work you will need to modify the ebrake handle or install one from a 93 car or move up to a 94/95 handle. You can Google this. My car is a 93 so I did not have to make the modification.

I'm starting with an 86 6 cylinder car, so a 7.5 rear end, so have to swap that out regardless. So I either need to swap for a fox 8.8 or an sn95 8.8. From my learning thus far I understand the fox are shorter, thats why I was going to get the sn95 and do the fox axle shafts with the mods to the bracket I have seen. I have a couple pair of certain wheels I'm planning to run so dont want to have any issue running them both. I appreciate all the info.

To answer this question. 94-95 Mustang axles have the brake lines mounted to the axle similar to the fox. It's a 3-channel ABS brake system with a single line to the rear like the fix cars.

96-98 went to 4-channel ABS and routed the brakes lines on the body so the axle is free of any lines. That means if you were to swap in an entire 96-98 axle, you need to buy and add lines.

so 94-95 would be the one the same as fox and easier swap? Regarding the whole brake, rear end, 5 lug scenario since I'm coming from and 86 6 cyl, would you recommend I do the whole sn95 94-95 swap of everything( spindle, caliper, rotor, brake booster, master cylinder, 8.8 rear with brakes and shorter fox lenth axle shaft)?

 

[Mustang5L5]

so 94-95 would be the one the same as fox and easier swap? Regarding the whole brake, rear end, 5 lug scenario since I'm coming from and 86 6 cyl, would you recommend I do the whole sn95 94-95 swap of everything( spindle, caliper, rotor, brake booster, master cylinder, 8.8 rear with brakes and shorter fox lenth axle shaft)?

So with regards to the actual 8.8 housing. It's 100% the same for 86-98. Mounting points, dimensions, etc. The actual housing is the same, so a 1998 axle is a bolt in affair.

The differences are what ford put on the axles. The brakes lines are one. But that is a minor issue.

The main issue is the disk brakes that Ford used in 1994 added 0.75" of width to each side. This was to provide clearance to the ABS tone rings on the axle. So if you bolt a 1994 rear into a fox, the mounting face for the rear wheels is pushed out 0.75" per side.

Now, with the correct wheels, this isn't an issue. I've run 18x9 with +35 offet and 265 tires and could actually put a spacer on and be fine. But when you put certain 9" or 10" rims on, it pokes out too far.

Because of that, thre exists the offset brackets you see. These brackets with fox length axles modify the rear track so there is no additional width.

One final thing to point out. Everything on the SN95 rear will transfer to the fox rear. So if you have a nicely rebuilt diff with 3.73's, you can just use the axle you have and swap the SN95 disk brakes over. You can take all the hardware plus axles and bolt it directly in. Or you can take parts of it. You can buy some 5-lug fox axles, the offset brackets, and then go buy a set of rotors and calipers and you are done. There are adapters for the brake lines, or you can buy a ready made set of lines.

There are many ways to skin a cat. The first question to ask is what wheels do you plan on running? Depending on that answer, may dictate which route you take.

 

[jaygee15]

@Mustang5L5 gotcha, from what I have read and seen on youtube , people are taking the sn95 complete rear end, and modifying the bracket(not sure what name of bracket is) on the end of axle(cutting a piece out and flipping to opposite side eg left to right and right to left) and then it fits fox length 5 lug.

i got a little confused on your mention of the 1998 axle, were you just using as an example that any 86-98 8.8 would bolt right it? Only reason I was looking at going sn95 axle vs fox 8.8 was from what I understand I would be killing two birds with one stone( 8.8 swap and brake upgrade)

I will be running either 93 cobra wheels or the saleen sc style wheels.

 

[AeroCoupe]

If you are going to run 93 Cobra wheels with the original offset then you will want to keep the SN95 rear end as is. The 93 Cobra rear end is basically a 87/88 Thunderbird Turbo Coupe rear end of which are both the same width as a 94-98 SN95 rear end.

The cut and flip is shown here in this thread:

Build Thread Thread 'Fox Length Axles And Stock Sn95 Brake Brackets'

Aug 3, 2012

Alright as many of you know, an SN95's axles are 3/4 of an inch longer than fox length axles. So, this puts the brake location out farther. Most people just go out and buy special bracket kits to make fox length axles work with SN brakes. Well I decided not to do this. Here's what I did:


I started off with no brakes on the rear end because that's how I bought it. Hopefully you guys can get yourself this far without assistance, because if you're going to tackle this, you should be able to simply remove calipers and bridges.

1) Remove the 4 nuts/bolts holding each of the brackets onto...

• 88LX5.Oh
• Replies: 37
• Forum: Fox 5.0 Mustang Tech

• 

Realize that the 94-98 V6 cars have a 7.5" housing however they use the same axles and brake setup as the V8's and Cobra's. Any 8.8 rear end from a 94-98 V8 or Cobra will be the same width with the only difference in the brake lines as Mustang5L5 pointed out.

Honestly unless you are going to be putting down some serious HP 31 spline is not necessary. I have 28 spline in both of my cars with trac-loks and have zero issues. Both cars are on drag radials and are 375 rwhp and somewhere around 500 rwhp (changed stuff since the last dyno). Now if you are going to put slicks one it and drag race I would say definitely move up to the 31 spline axles.

If you pay attention to the backspacing and offset you can get a 10" wide wheel and 295 with tires under the sheet metal (rolling the fender lips and some light massaging of the inner fender with a dead blow) minus the quad shocks. I will say I do not think you can get much more than a 275 width tire under one with a panhard bar due to the way the body moves over the rear end. I currently have 275/40R17 Nitto 555 R2's under the Coupe with a 94-98 width rear end and the wheels are 17x9 with a 45mm offset which is a 6.75" backspace.

I am just going to point out that the wheel selection for a Fox Mustang running a 94-98 SN95 width rear end is just about endless or at least that is what I thought when I was looking for new wheels 2 years ago.

 

[Mustang5L5]

i got a little confused on your mention of the 1998 axle, were you just using as an example that any 86-98 8.8 would bolt right it? Only reason I was looking at going sn95 axle vs fox 8.8 was from what I understand I would be killing two birds with one stone( 8.8 swap and brake upgrade)

Yes, I was just using it as an example. Any 86-98 housing will bolt right in.

 

[Noobz347]

Ha! For some reason, I thought the entire housing was different.

My mistake.

 

[Mustang5L5]

There are differences in the 99-04 housing.

the LCA bolt holes are 14mm vs 12mm in the 86-98 housing.

Biggest differences however is the housing is approx 0.75” wider each side. Combined with the longer axles and this adds approx 1.25” of width to each side.

 

[Noobz347]

There are differences in the 99-04 housing.

the LCA bolt holes are 14mm vs 12mm in the 86-98 housing.

Biggest differences however is the housing is approx 0.75” wider each side. Combined with the longer axles and this adds approx 1.25” of width to each side.

I had to read that a couple of times and get the years straight.

We need to make a damned Mustang Trivia game.



For twenty points:
"In 1986 the Ford Mustang went to an 8.8 inch rear axle housing. Until what year, did Ford use this housing in the Mustang without modification?"

 

[jaygee15]

If you are going to run 93 Cobra wheels with the original offset then you will want to keep the SN95 rear end as is. The 93 Cobra rear end is basically a 87/88 Thunderbird Turbo Coupe rear end of which are both the same width as a 94-98 SN95 rear end.

The cut and flip is shown here in this thread:

Build Thread Thread 'Fox Length Axles And Stock Sn95 Brake Brackets'

Aug 3, 2012

Alright as many of you know, an SN95's axles are 3/4 of an inch longer than fox length axles. So, this puts the brake location out farther. Most people just go out and buy special bracket kits to make fox length axles work with SN brakes. Well I decided not to do this. Here's what I did:


I started off with no brakes on the rear end because that's how I bought it. Hopefully you guys can get yourself this far without assistance, because if you're going to tackle this, you should be able to simply remove calipers and bridges.

1) Remove the 4 nuts/bolts holding each of the brackets onto...

• 88LX5.Oh
• Replies: 37
• Forum: Fox 5.0 Mustang Tech

• 

Realize that the 94-98 V6 cars have a 7.5" housing however they use the same axles and brake setup as the V8's and Cobra's. Any 8.8 rear end from a 94-98 V8 or Cobra will be the same width with the only difference in the brake lines as Mustang5L5 pointed out.

Honestly unless you are going to be putting down some serious HP 31 spline is not necessary. I have 28 spline in both of my cars with trac-loks and have zero issues. Both cars are on drag radials and are 375 rwhp and somewhere around 500 rwhp (changed stuff since the last dyno). Now if you are going to put slicks one it and drag race I would say definitely move up to the 31 spline axles.

If you pay attention to the backspacing and offset you can get a 10" wide wheel and 295 with tires under the sheet metal (rolling the fender lips and some light massaging of the inner fender with a dead blow) minus the quad shocks. I will say I do not think you can get much more than a 275 width tire under one with a panhard bar due to the way the body moves over the rear end. I currently have 275/40R17 Nitto 555 R2's under the Coupe with a 94-98 width rear end and the wheels are 17x9 with a 45mm offset which is a 6.75" backspace.

I am just going to point out that the wheel selection for a Fox Mustang running a 94-98 SN95 width rear end is just about endless or at least that is what I thought when I was looking for new wheels 2 years ago.

I imagine they are original offset. I havent got that far to have looked into offset of aftermarket ones etc. Why would I want to keep the sn95 as is instead of a bit shorter with the fox length axles? Sorry that confused me, all these things bring up new questions. Sucks being a newbie sometimes lol.

So the v6 sn95 have 7.5 rear end, I thought they all had 8.8. So I will need a v8 sn95.

I was planning on initially putting about a 500hp 408 stroker in, and maybe one day adding turbo, but maybe not.

 

[Mustang5L5]

I imagine they are original offset. I havent got that far to have looked into offset of aftermarket ones etc. Why would I want to keep the sn95 as is instead of a bit shorter with the fox length axles? Sorry that confused me, all these things bring up new questions. Sucks being a newbie sometimes lol.

Because 1993 Cobras had disk brakes that also push the rear wheels out 0.75" each side like the SN95 cars.

So if these are original offset, 5-lug wheels you would want to keep that axle lenght from the SN95 cars.

However vast majority of 5-lug reproduction 93 cobra wheels have an offset that better works with fox length axles, so you want to check on this.

 

[limp]

I don't personally, recommend this route. Do the conversion to a Fox length axle housing. An SN95 axle on a Fox creates more issues than it solves IMO.


For the brakes:

Mustang Rear Disk Brake Caliper Adapter Brackets For 94-04 GT/V6 Calipers (79-93)

Check out these rear brake adapter brackets for your 79-93 Mustang Foxbody! Install 94-04 Gt/V6 Calipers

lmr.com

You will also need to order a set of axles.

I'd also choose this time to upgrade to a 31-spline F-150 Trac-Lok, but that's just me.

When going from 28 spline to 31, it is surprising how much larger the axle is....

 

[limp]

The emergency brake was one reason I kept my rear brakes drum..... Pulled out the E brake cable from the old housing and backing plates and it plugged right into my new 11" drums on my 9 inch .... I was pretty surprised at how well it went.... Works just like it was from the factory...

 

[AeroCoupe]

The LMR reproduction five lug 93 Cobra wheel is a wider wheel than OEM and the offset is larger which pushes the wheel further outward by 24mm or about 1".

https://lmr.com/item/LRS-1007RSL5/5-Lug-93-Cobra-Wheel-LH-17x85-Silver

Specs:

Diameter	17"
Width	8.5"
Bolt Pattern	5x114.3 mm.
Offset	+30 mm.
Backspacing	5.9 in.
Centerbore	70.6 mm.
Weight	29 lbs

OEM four lug Cobra wheels specs:

1993 Cobra Wheel Specs:
RH: F3ZZ-1007-A
LH: F3ZZ-1007-B
Diameter: 17"
Width: 7.5"
Bolt Pattern = 4 X 4.25"
Offset = 1.61" or 40.9mm
Backspace = 5.36"

Also, Makers Garage has 18" five lug replica 1993 Cobra wheels here:

Fox Body Cobra Wheels: Chrome 5-Lug 18x8.5/9.5 Set

Enhance your Fox Body Mustang with reimagined chrome Cobra wheels. This 5-lug set includes 18x8.5 and 18x9.5 wheels for a sleek, stylish upgrade.

makers-garage.com

Specs:

• FRONT WHEEL SPECS
  • (2) 18″x8.5″ (L&R Directional)
  • Finish: Chrome Wheel – Chrome Center Cap
  • 5 Lug x 114.3mm
  • Backspace: 5.75″
  • Hub Bore: 70.6
  • Weight: 25.10lbs
  • Knurled Inner Bead
  • Serial Numbered
  • SAE J2530 Certified

• REAR WHEEL SPECS
  • (2) 18″x9.5″ (L&R Directional)
  • Finish: Chrome Wheel – Chrome Center Cap
  • 5 Lug x 114.3mm
  • Backspace: 6.125″
  • Hub Bore: 70.6
  • Weight: 28.12lbs
  • Knurled Inner Bead
  • Serial Numbered
  • SAE J2530 Certified

You can do the wheel comparisons here:

https://www.1010tires.com/Tools/Wheel-Offset-Calculator?srsltid=AfmBOoqPqPh0xiLHX9Ch_WlK7GQXCFQ2omWfAzJPqwQmmz8bKj5hZ3mi#

 

[FastSVO]

I am trying to figure out the correct part number when upgrading to the "big bore" 15/16" wheel cylinders on a stock fox body. What I have so far is Wagner part number WC 34876, but everything online is suggesting that these are 13/16" in size.

Can anyone please confirm or recommend the correct part number?

Thanks!

 

[Mustang5L5]

I am trying to figure out the correct part number when upgrading to the "big bore" 15/16" wheel cylinders on a stock fox body. What I have so far is Wagner part number WC 34876, but everything online is suggesting that these are 13/16" in size.

Can anyone please confirm or recommend the correct part number?

Thanks!

‘89 Ford Bronco had the 15/16” wheel cylinders.

Thing is I don’t know the compatibility with the Mustang drum brake. Given they are $10 each on Rockauto, might be worth buying one to test out.

 

[AeroCoupe]

Do the 9” and 8.8 cylinders interchange? I know Maximum Motorsports has large bore cylinders but they give no data on them other than what setups to run them in.

Big-bore rear wheel cylinders, 1979-1993 Mustang with 9" drum brakes (pair)

For $80 a pair I would just start looking at cylinders at the pars store until I found what I needed.