8.8 Rear End Swap and GM Brakes

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leefybeaver

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Jul 23, 2012
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Hey All, so I will be moving forward with 2004 Mustang 8.8 swap in my 84 Regal. I think I have everything I will need to get the diff test fit with wheels and the suspension and alignment, so I'm covered there. I'm struggling with the brakes. I have been scouring the internet (lightly) for the best way to adapt the Ford brakes to GM brakes. Is there is universal or alternate rotor that has a GM 5x4.75 bolt pattern that I cant easily find. This will obviously let me use all the existing hardware. I could do something similar to what I'm doing below for the axle and just drill a stock replacement rotor with a similar template. I'm open to cutting the brackets and using a disc brake kit to make work. Will some of 7.5 / 8.5 kits work? Not looking for an expensive Wilwood kit or anything like that. Something that will use stock Camaro or Corvette brakes is good, or whatever is common and readily available. Just wondering what the rest of you out there are using and what the experience is.

Now I have DIY plan for drilling the axle to get he the 5x4.75 stud pattern on the Ford axle for the test fitting. See 3D printed drilling template image below, for sale soon (along with bezels and other things you may want)! The holes are a snug fit for the existing 114.3 stud pattern. The nipples sticking out have a small hole (not visible) for a pilot hole to be drilled in the axle, and the nipple will serve a guide for the actual drill size for the stud. Should make for an easy solution to that problem, and one day I can get new axles if necessary.

IMG-20210107-WA0000.jpg


That's the input I'm looking for today. Don't hate on my rear end choice, I know it's longer that stock...

Thanks.
 
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UC645

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Apr 20, 2020
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Arent the 05 and up Mustang housings a different animal to the Fox/SN95 ones? How are you planning on shoehorning one of those in there?
 

ostrich

Master Mechanic
Aug 27, 2012
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I may have miss typed 05 for 04! 04 is a bit wider...but I think it will be okay.
I just finished my parking brake cable on an 8.8 conversion in my 85MCSS. Not sure what you are using for axles, I got a need pair from Moser for an 8.8 with Chevy lug bolt pattern on the end so I can keep my wheels. I ended up upgrading the rear mustang discs to Cobra R ones, bigger bracket & rotors, same mustang calipers. Then I re-drilled stock Mustang rotors for the Chevy bolt pattern. The rotors are hub centric.
 
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UC645

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Apr 20, 2020
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I may have miss typed 05 for 04! 04 is a bit wider...but I think it will be okay.
Ah I got you, the SN95 housings aren’t any different from the Fox housings, the axles are a bit wider thanks to the ABS tone rings on them. That being said, I don’t believe it’s possible to fit GM drums or any stock type disk brakes on the small Ford housing ends, with those axles anyway.
Using Foxbody 5 lug conversion axles may allow you to use the g body drums with spacers behind the drums but I never followed through with that idea. If you decide to tackle that, but custom axles with a GM bolt pattern.

The other route is if the axle you have is complete down to the brake assemblies, use them as is. The only real modification you’re going to need to do is swapping the ends from the Mustang parking brake cables on to the G body ones. The ends come off the Mustang cables relatively easily as seen here: https://www.ffcars.com/threads/mk4-e-brake-cables-too-long.298117/
Im in the process of doing this currently, and can’t say how feasible it is.

There may be another way to do this as noted in the post above from ostrich. Speaking of, can you explain what you did to your cables?
 

ostrich

Master Mechanic
Aug 27, 2012
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Ontario, Canada
Ah I got you, the SN95 housings aren’t any different from the Fox housings, the axles are a bit wider thanks to the ABS tone rings on them. That being said, I don’t believe it’s possible to fit GM drums or any stock type disk brakes on the small Ford housing ends, with those axles anyway.
Using Foxbody 5 lug conversion axles may allow you to use the g body drums with spacers behind the drums but I never followed through with that idea. If you decide to tackle that, but custom axles with a GM bolt pattern.

The other route is if the axle you have is complete down to the brake assemblies, use them as is. The only real modification you’re going to need to do is swapping the ends from the Mustang parking brake cables on to the G body ones. The ends come off the Mustang cables relatively easily as seen here: https://www.ffcars.com/threads/mk4-e-brake-cables-too-long.298117/
Im in the process of doing this currently, and can’t say how feasible it is.

There may be another way to do this as noted in the post above from ostrich. Speaking of, can you explain what you did to your cables?
Sure, just finished them. Ended up using a stock 85SS passenger cable, just how it is. Used an 85SS driver cable 'sleeve', cut the bullet off the end and pulled the cable itself out. It ends up being about 3-4" short. Bought a parking cable from a Sierra truck (ACDELCO 18P2759, 82" long). Cut the bullet off of the cable then threaded that into the driver's sleeve, out the caliper end. Then cut a banjo bolt down to make a new bullet (used the hole in it to insert the cable). took out the slack & welded it to the end of the cable. The front cable is also stock for an 85SS. Adjusted the cables with the nut etc. like stock. Need to do some final adjustments and bleed the brakes, but will hold the wheels right now.
 

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ostrich

Master Mechanic
Aug 27, 2012
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Forgot one thing. I did weld 2 mounts on the axle tube for the caliper end cable. Basically where you push the end of the cable into and the 3 prong clip holds it. At work, I can get some pics later. Basically an 'L' bracket with a 1/2'-9/16" hole
 
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UC645

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Apr 20, 2020
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Sure, just finished them. Ended up using a stock 85SS passenger cable, just how it is. Used an 85SS driver cable 'sleeve', cut the bullet off the end and pulled the cable itself out. It ends up being about 3-4" short. Bought a parking cable from a Sierra truck (ACDELCO 18P2759, 82" long). Cut the bullet off of the cable then threaded that into the driver's sleeve, out the caliper end. Then cut a banjo bolt down to make a new bullet (used the hole in it to insert the cable). took out the slack & welded it to the end of the cable. The front cable is also stock for an 85SS. Adjusted the cables with the nut etc. like stock. Need to do some final adjustments and bleed the brakes, but will hold the wheels right now.
Forgot one thing. I did weld 2 mounts on the axle tube for the caliper end cable. Basically where you push the end of the cable into and the 3 prong clip holds it. At work, I can get some pics later. Basically an 'L' bracket with a 1/2'-9/16" hole
That’s a pretty trick way to go about this.
 

JAMCAR223

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Jun 6, 2014
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Still waiting on those pics... I have an 8.8" I'd like to put in a '78 Aero car one of these days.
 
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64nailhead

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Dec 1, 2014
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I opted out on the parking brake - probably shouldn’t have, but I did (weight thing.)

I like the rotor drilling fixture - where did you find that?

I used an Exploder rear and factory disc brakes. Quite easy imo. I recently just completed converting it 9” New style Torino wheel ends and still employed the factory Exploder brakes. Needed 2 spacers that aren’t documented anywhere that both spacers are needed.

Regarding looking for a weld on brake option - with no parking brake - Afco, AllStar Performance and others make a weld in bracket that uses a GM metric caliper with an F-body disc. You can use the ‘Seville’ caliper that incorporates the parking brake cable. Locally, all of the circle track speed shops can get, or have, these brackets and calipers on the cheap - and they work.
 
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