Fox T-Bird/Cougar Forums

Technical => Drivetrain Tech => Topic started by: count on April 17, 2021, 08:31:10 PM

Title: Axle swap
Post by: count on April 17, 2021, 08:31:10 PM
OK I know this horse been beat to death but let’s beat it a different way.  I recently want to a u pull it salvage yard I spent the day collecting calibers rotors brackets spindles hubs I guess you can see where I’m going with this yeah I was collecting for a 4-5 lug conversion it was going good until when I realized Man these axles are a little bit long.  this mustang is not the 96 8.8 V8 I came for but the 1999
Why I didn’t notice the Dual caliber, I don’t know.
But my question is can I still use this axles (30.75)length in my 88 sport.  ( the salvage yard combined with hour drive I would rather not make that trip again if I don’t have too plus a lot of seized bolts)
Title: Re: Axle swap
Post by: Aerocoupe on April 18, 2021, 12:24:16 AM
Nope.  You need the 94-98 axles to keep the stock  to  measurement.  The front brakes are a nice upgrade being they have the dual piston caliper.  If you snagged the spindles they are not ideal on a stock k-member car due to their geometry but that can be dealt with via a bump steer kit.  I opted to go with the 96+ spindles on my stock k-member car as I knew a tubular k-member was going to happen and did not want to try and se up a set of the 94-95 spindles.

You do realize that the 94-98 GT and V6 cars have the exact same brakes, right?  In the rear the axles, brackets, dust shields, and calipers are the same.  Only difference is the housing in that one is for the 7.5 ring gear and the other is for the 8.8 ring gear.  As for the front they are straight across the same.  I pulled both my swaps from V6 cars being I already had the 8.8 housings and was converting from drum brakes.
Title: Re: Axle swap
Post by: Beau on April 18, 2021, 12:29:25 PM
Yup, what Darren said. I know it sucks, but really, any rear from '94-98 will yield the axles you want. AFAIK, the brakes are the same across all those years, so what you already have harvested will do for you. (I'd probably spring for remanned rear calipers, when those shiznits seize, they're a pain, unless you have the stuff to take 'em apart and know how)..

I had/have what amounts to the same setup on both my Thunderbird and now on my '87 Mustang. Up front is the dual piston calipers,

On my 'Bird I had a  setup....used the stock Tbird Sport's backing plates, '97 Stang V6 axles (again, no matter if it's V6 or V8, the shafts themselves are the same), but I kept that car drums, and used Mercury Marquis drums, these were 10" drums and not the usual 9". With that setup, I HAD to have the Sport's back plates, all others were 9" drums, so....there's *probably* a way, but with all the Mustang shiznit in the yards now, no reason not to step up to dscs. I just did it to see if it could be done.

Now in my Mustang, I ran Ranger axles and kept the stock drums. There was no way to make a hybrid system as the axles are too short for that setup.

When I get the T5 rebuilt, I'll probably be swapping to discs and throwing a 3.73 in with a new Trac Lok.


BTW, if you've not ran the PBR calipers yet, holy shiznit, you'll feel like you're going to leave your teeth in the steering wheel.. LOL
Title: Re: Axle swap
Post by: Chuck W on April 18, 2021, 12:42:52 PM
Looking a the axle chart listed in the pinned thread in this section (HERE (https://drive.google.com/file/d/1tKW8TNLJ8Ex-8fpnB8Syw9-fiW4vK7WM/view)

I have postulated that MAYBE you could use the 99-04 axles and brake set up on your wide 7.5 housing in your Sport. The numbers are really close. At least according to the chart.

You would need to swap to the rear discs though, and your  to  width would be 1.5" wider.
This is all just a guess though.

If you're keeping the drums, you'll need to either have your current axles converted to 5-lug or buy new, custom ones and use some Ranger drums.

94-98 Axles won't work in your wide housing. The bearing surfaces are in the wrong location. If your car was an 83-85, you'd have the narrow housing that would work with the 94-98 axles.

Title: Re: Axle swap
Post by: JeremyB on April 18, 2021, 03:05:34 PM
It's been a minute, but I'm running 99-04 axles  and SN95 solid discs in my 87 7.5" rear end.

On paper it works perfectly, but I had to put small spacers to get the disc and caliper to properly align IIRC.
Title: Re: Axle swap
Post by: Beau on April 18, 2021, 08:14:30 PM
Chuck is right..I forgot about that oddball OAL length. My bad.
Title: Re: Axle swap
Post by: Aerocoupe on April 19, 2021, 12:00:09 AM
So from what I understand (Chuck or Eric correct me here) is that the:

1) 87-88 Turbo Coupes had the 8.8 rear end that was the same housing width as the 86-98 Mustang 8.8 housing and were disc brake.
2) The 88 XR-7 Cougar had a drum brake 8.8 that was the same width as the Turbo Coupe rear end from axle  to axle  but the housing is the same as the 86-98 Mustang 8.8 housing and not very common.
3) There were some 87-88 Thunderbirds that had an 8.8 with drum brakes but I believe the housing was wider like the 7.5" housings.

I looked at the chart and the XR-7 is not discussed not is any type of 8.8 drum brake rear end.
Title: Re: Axle swap
Post by: EricCoolCats on April 19, 2021, 08:17:58 AM
So from what I understand (Chuck or Eric correct me here) is that the:

1) 87-88 Turbo Coupes had the 8.8 rear end that was the same housing width as the 86-98 Mustang 8.8 housing and were disc brake.
2) The 88 XR-7 Cougar had a drum brake 8.8 that was the same width as the Turbo Coupe rear end from axle  to axle  but the housing is the same as the 86-98 Mustang 8.8 housing and not very common.
3) There were some 87-88 Thunderbirds that had an 8.8 with drum brakes but I believe the housing was wider like the 7.5" housings.

I looked at the chart and the XR-7 is not discussed not is any type of 8.8 drum brake rear end.

1) Correct.

2) Correct.

3) I don't believe any 1987-88 non-Turbo Coupe/1988 non-XR7 got an 8.8" rear. At least, I've never found any evidence. Even the 1987 XR-7's got the 7.5" rear. Now in 1988 only, the rear drums went to 10" regardless of model, and that was for V6 and V8 cars. (I have heard from a few people that their car still had 9" drums but those are exceptions).

It is possible to take an 8.8" housing and use T-Bird/Cougar axles, backing plates, and 10" drum hardware and make your own 8.8" drum rear.
Title: Re: Axle swap
Post by: Chuck W on April 19, 2021, 08:18:11 AM
So from what I understand (Chuck or Eric correct me here) is that the:

1) 87-88 Turbo Coupes had the 8.8 rear end that was the same housing width as the 86-98 Mustang 8.8 housing and were disc brake.
Correct.

2) The 88 XR-7 Cougar had a drum brake 8.8 that was the same width as the Turbo Coupe rear end from axle  to axle  but the housing is the same as the 86-98 Mustang 8.8 housing and not very common.
Correct. There was a V8 Cougar that had an 8.8 drum brake rear. Narrow housing. Longer axles.
 
3) There were some 87-88 Thunderbirds that had an 8.8 with drum brakes but I believe the housing was wider like the 7.5" housings.
No. There were no 8.8's in any other 83-88 Tbird, other than mentioned in #1 and #2. All 86-88 TBIrds/Cougars (Not listed above) had the wide housing 7.5.

I looked at the chart and the XR-7 is not discussed not is any type of 8.8 drum brake rear end.
Title: Re: Axle swap
Post by: Aerocoupe on April 19, 2021, 09:21:56 AM
Great info guys and thank you for the clarifications.
Title: Re: Axle swap
Post by: Beau on April 19, 2021, 11:45:23 AM
To aid in distinction (that is, if there are any of these left in yards by now) the 9" drums were all finned, the 10" were smooth..

I have heard of some '88 Cats that had the bit drum 8.8 but have never seen any, either here on the forum or in junkyards. Have came across a few '88 XR7 cars in yards but all had the 7.5 but 10" drums.

Title: Re: Axle swap
Post by: EricCoolCats on April 19, 2021, 12:17:20 PM
Beau, close... 9" were finned, 10" were smooth.
https://www.coolcats.net/restoring/brakes.html

I appreciate that Ford put larger drums on at the end of the run. That's something they commonly do for whatever reason. The 1997 Cougars/T-Birds all got 4-wheel disc standard, and the front rotors were larger, just for that last model year of the body style. So I guess our cars set the precedent for that LOL.
Title: Re: Axle swap
Post by: count on April 19, 2021, 12:19:49 PM
It's been a minute, but I'm running 99-04 axles  and SN95 solid discs in my 87 7.5" rear end.

On paper it works perfectly, but I had to put small spacers to get the disc and caliper to properly align IIRC.

So you you were able to use axles from 99-04 and they worked with spacers? What kind of spaces and where did I you place them? 
Title: Re: Axle swap
Post by: Chuck W on April 19, 2021, 12:45:26 PM

So you you were able to use axles from 99-04 and they worked with spacers? What kind of spaces and where did I you place them? 


More than likely on the caliper mounting bracket locations, to get the caliper better centered over the rotor.
It will be pretty evident when you bolt it all up.
Title: Re: Axle swap
Post by: count on April 19, 2021, 08:43:19 PM
This thread has yielded some good information but I’m alittle confused “will these 99 mustang axles work with some spacing or it’s a unstable setup all together?  JeremyB seems to have had some success with axles. And by the way I appreciate everyone’s input. Aerocoupe, chuck W, Eric, jeremyB and beau.
Title: Re: Axle swap
Post by: Chuck W on April 19, 2021, 08:59:14 PM
If you look at the chart I linked, the dimensions aren't 100% the same between the two set-ups. When you install the axles and go to bolt up the brakes, you will probably find that the rotor is not centered in the opening in the caliper mounting bracket.
 
Seeing as you have to add spacers, I'm betting it's slightly inboard a bit and needs to be pushed outboard to center it all up.
Spacers/washers between that bracket and the mounting  on the axle would be needed to accomplish this.
Title: Re: Axle swap
Post by: count on April 19, 2021, 09:21:54 PM
Great chart!  I had this chart saved in my files the whole time.  Thanks!
Title: Re: Axle swap
Post by: Vintage on April 20, 2021, 09:57:07 AM
So from what I understand (Chuck or Eric correct me here) is that the:

1) 87-88 Turbo Coupes had the 8.8 rear end that was the same housing width as the 86-98 Mustang 8.8 housing and were disc brake.
Correct.

2) The 88 XR-7 Cougar had a drum brake 8.8 that was the same width as the Turbo Coupe rear end from axle  to axle  but the housing is the same as the 86-98 Mustang 8.8 housing and not very common.
Correct. There was a V8 Cougar that had an 8.8 drum brake rear. Narrow housing. Longer axles.
 
3) There were some 87-88 Thunderbirds that had an 8.8 with drum brakes but I believe the housing was wider like the 7.5" housings.
No. There were no 8.8's in any other 83-88 Tbird, other than mentioned in #1 and #2. All 86-88 TBIrds/Cougars (Not listed above) had the wide housing 7.5.

I looked at the chart and the XR-7 is not discussed not is any type of 8.8 drum brake rear end.

#3 is not correct.  I have a late-build (manufactured date July 1988) Thunderbird Sport that csme with the factory 8.8 axle and 10" smooth drums. Up until a year ago it was factory stock right down to the lers, plug wires, plugs, and air silencer in the fender.

I attached a pic of the door jamb label with VIN, manuf date, trim and axle codes, etc if anyone is interested.
Title: Re: Axle swap
Post by: Chuck W on April 20, 2021, 12:42:32 PM

#3 is not correct.  I have a late-build (manufactured date July 1988) Thunderbird Sport that csme with the factory 8.8 axle and 10" smooth drums. Up until a year ago it was factory stock right down to the lers, plug wires, plugs, and air silencer in the fender.

I attached a pic of the door jamb label with VIN, manuf date, trim and axle codes, etc if anyone is interested.


You have an exception, and not the rule, at the end of the build cycle for that platform.

It could be similar to the '88 XR-7 in that respect (the 8.8 ), but also many V8 Sports came with the 7.5.













Title: Re: Axle swap
Post by: Vintage on April 20, 2021, 01:21:57 PM

#3 is not correct.  I have a late-build (manufactured date July 1988) Thunderbird Sport that csme with the factory 8.8 axle and 10" smooth drums. Up until a year ago it was factory stock right down to the lers, plug wires, plugs, and air silencer in the fender.

I attached a pic of the door jamb label with VIN, manuf date, trim and axle codes, etc if anyone is interested.


You have an exception, and not the rule, at the end of the build cycle for that platform.

It could be similar to the '88 XR-7 in that respect (the 8.8 ), but also many V8 Sports came with the 7.5.

Right. They do exist. I have seen one other 88 Bird that was an LX with the 5L option, was NOT a Sport, and it also had the drum 8.8.  Actually I tried to buy it about 5 yrs ago, as it was a cream puff garage queen owned since new by a senior, but he would not let it go.
Title: Re: Axle swap
Post by: EricCoolCats on April 20, 2021, 03:37:34 PM
One thing I've learned from owning Fords is to never say 'never' when it comes to non-standard options. All these years later and we're still discovering things.

But Chuck is right, it was the end of the run and there were a bunch of 8.8" rear ends laying around to use up. Just for a bit of background info, there were around 15,000 XR-7 models in 1987, and those all had the 7.5" rear which were also shared on the non-XR-7 models so no biggie. For 1988 Ford ordered up the 8.8" for just the XR-7, and again about 15K of those were sold. But with orders getting canceled, the popularity of the '88 model, market conditions, etc. Ford probably needed more 8.8" rear ends than what it projected in the first place. So having some left over at the end of the model run, Ford likely authorized using them up. I haven't seen any official spec sheets or changes on that, but it's very difficult to find those today, and also right before the model year changes it gets really REALLY crazy in auto manufacturing. They'll throw anything on a car just to get rid of it LOL.

I heard from a few people over the years that claimed to have 1984 taillights on an early '85 model. Some early 1984's came with the 1983 upright hood ornament. We have dospoogeented the taillight harness changes between 1987 and 1988. Anything is theoretically possible, but just not likely unless you've got proof. And 90%+ of claims go unproven, lemme tell ya.

So we know these unicorns are out there, and that's wonderful as they are definitely out of the norm and a cool thing to have if you've got one and can prove it. Good on ya, Vintage, that's awesome.
Title: Re: Axle swap
Post by: Beau on April 20, 2021, 03:58:25 PM
Yeah I saw there were new replies to this, was checking back posts and realized I got it backwards. Glad you set me straight, and I edited my post ;)

Oh, things one forgets when he hasn't touched a Thunderbird in years...and I need to do something about it...
Title: Re: Axle swap
Post by: count on April 21, 2021, 06:26:48 AM
vintage it seems that my door sticker is very similar to yours. Definitely have the same axle codes
Title: Re: Axle swap
Post by: Chuck W on April 21, 2021, 07:11:32 AM
vintage it seems that my door sticker is very similar to yours. Definitely have the same axle codes

Then you should look at your axle to verify what one you have.

If you do have an 8.8, then it is probably the "narrow" housing (Measure the "B" dimension from the chart).
If that's the case, the 99-04 axles will not work for you, in any fashion.

The upside, 94-98 axles will, and bare minimum you can redrill/mod your existing drums to work. (I ran 94-98 axles in my '84 XR-7 with modded drums for a while).
Title: Re: Axle swap
Post by: Vintage on April 21, 2021, 02:16:27 PM
vintage it seems that my door sticker is very similar to yours. Definitely have the same axle codes

Yeah, you might have the 8.8 axle since your build date is getting close to mid-1988. If you dont have time right now to jack it up and look to make sure, then turn on the flash for the camera on your cell phone and lay down next to the back tire and take a pic of the diff cover. 8.8 has 4 straight sides, the 7.5 has curved sides on left and right.
Title: Re: Axle swap
Post by: count on May 01, 2021, 10:52:24 PM
So after rereading thread I decided to go back to parts yard to pull 96 axles.  looking at my TC 8.8 , I started wondering if I should have taken caliper mounting bracket. Do anyone know if the TC caliper mounting bracket will work with sn95 rear disc brake setup?
Title: Re: Axle swap
Post by: Aerocoupe on May 02, 2021, 09:58:46 AM
Nope. Completely different setup.  You want everything from the axles out.
Title: Re: Axle swap
Post by: Bigfreeb on December 31, 2022, 02:05:37 PM
I know this is an old thread and I hope someone is still out there with knowledge. I have an 86 T-bird V-6 auto 7.5 rear. I went to pick and pull got everything from the rear of a 1996 V-6 mustang. When I put it all together everything bolted right up till I got to the axles. First the axles would not go in all the way because they step up where seal rides. I removed the seal to continue test fitting and with the axle in place it's off by .750". When I went back and made some measurements to get the rotors centered in the brackets I need .750". It looks like I need 99-04 axles for this set up. I just ordered new ones from Rock auto wish me luck. Any info would helpful.
Thanks
Title: Re: Axle swap
Post by: Chuck W on December 31, 2022, 02:33:44 PM
The answer to your question is right HERE (https://www.foxtbirdcougarforums.com/index.php?topic=13253.msg138359#msg138359) on the forum.

The 86-88 Tbird/Cougar 7.5 is wider than all of the Fox and 94-98 housings.

The 99-04 housing is a similar width to that 7.5, but the axles are each 3/4" longer, thus the axles you ordered from RA will not work.

If you're keeping the 7.5, why not just use the whole 96 V6 axle, housing and all? The overall width  to  is the same as what you have and you can use the disc brakes?