Fox T-Bird/Cougar Forums

The Sport has a Turbo Coupe 8.8 with 9 inch drum brakes on it. Can the 1987/88 7.5 rear 10 inch drums work on this rear?

I was thinking they would have to be spaced out a bit to fit right. Anybody know?

I don't think. The TC rear housing is the Mustang width with T-Bird width axles. I don't think the drums would have the right offset

Until I found the 8.8 with rear drums out of an XR7, I was running a TC rear with 10" drums (didn't want to be bothered switching to rear discs). The rear wheels did sit in a bit, but did not rub. Can't remember what axles I used though, it was several years ago.

I really don't want the wheels to sit inboard.

I just need to find a nice TC rear in good shape around here with all of the hardware.

The housing is the same length, stang or bird. the axles are different lengths as well as drums

If you swap the hardware from 10" drums and you have tbird axles you should be set. honestly, I doubt its worth the trouble though.

I'm thinking the same thing Haystack. I believe the 8.8 is a wee bit narrower than the 7.5 housing although they do share the longer T-Bird axles.But I do think for now I'll just keep the nine inch brakes until I can locate a disc rear near me down here.

I did the 10" drum swap to my TC rear...my wheels are positioned normally. Now, as long as you have some Sport 10" brake drum backing plates, I think you could do this with the TC axles. The TC axles are identical in length to the SN95 (5 lug) axles I used.

In fact, the only difference between the 2 swaps would be the axle's lug count..

But you MUST have the '83-'85 10" drum backing plates to work with the Tbird length axles. And of course then you'll need the 10" drums and the requisite brake hardware...and that's available at any parts store.
You have the TC rear in now, right? (You can also use a Fox Stang 8.8....the housing itself is the same width. The difference in overall width comes from the (TC) axles, which you'll be using since you wish to stay 4 lug.

The difference seems to be in the backing plates, however, my 5 lug Crown Vic drums are also deeper, so with my setup using the '87-'88 Sport backing plates, the deeper drums allowed for the difference. Apparently I need to go back and edit my swap thread with this info.

The combo of axles, drums, and backing plates must be kept in mind, or you'll have an offset issue as Carm mentions.

Ad I don't know if there is a 4 lug, 10" drum that is "deeper" like the Crown Vic drum that will enable the later 10" drum's backing plates to work with the 21.95" axles, such as the SN95, and the Tbird/Cugar axles.

Well, I ordered a new brake drum for the 9 inch brakes. The 10 inch brakes are at the yard on a V-6 car. I may get them. Not sure yet. May wait for a TC rear that is COMPLETE.

The ONLY reason i went with the drum setup was because I didn't want to mess with the master and prop valve work, as well as every rear disc brake rear I found, the calipers were seized, or were already missing parts.

After I hear something about the new job in a couple of weeks, I'll either be selling ALL my Ford stuff, (if I don't get it) or once I get some things squared away, I'll be looking at getting rear discs for the Sport, and going back to that plan, but at the time I did the drums, it was a matter of money, ease, and quickly getting the car in a drivable state.

Anywho, Vinnie, I've got the sway bar dragged out of storage, and will have it ready to go tomorrow...I just need a destination, and I can't quite remember your details lol.

I just put a '92 mustang rear end in my '88 Sport and when I put them in I swapped the backing plates and put my 10" drums on the Mustang housing. If you wanted to put the 10" drums I would think the TC housing you would need some Mustang length axles. And with that setup the rear wheels do sit noticeably inboard on the car. You would either need spacers or some high offset wheels to counter that.

Just be aware that the plumbing is different between the Mustang and TB rear ends. I had to use the brake lines from the Sport housing and mess with them until they fit the Mustang width one.

I really think I'm going to wit until I can get a complete TC rear. Or find a complete disc swap kit at the right price.

No sir. The Stang 8.8 and the TC 8.8 HOUSINGS themselves are the same (not the axle  to  width).
 It's the axles that give the inch..inch and a half extra width to these cars compared to the Fox Mustang. The '87-93 Mustang axles, regardless of 7.5 or 8.8 are shorter. :)
 You can put TC axles in your housing right now (not counting the brake stuff you'd need) and your track width would be back to what it should be. In fact, if you find the proper brake parts, it's easily done.

I did a swap/conversion a year ago, in which I swapped SN95 axles into a TC rear, with Sport backing plates, and 10" drums from a 1988 Crown Vic. 5 lug drums, stock rear track width, and keeping my 7.5 rear's brake line was the goal, and it worked.

Now, if Vinnie wanted to go this route, it would be much the same, only he'd need an 8.8 rear from either a TC, or an '86-98 V8 Mustang, and ANY 4 lug Tbird/Cougar axles, as they were ALL the same length. He'd also need Sport backing plates, and the Sport brake drums to keep keep 4 lug, but have the big drum setup.

There's a chart in .PDF, I don't know how to embed it here, but that's my source, and Chuck W here, and some others compiled some info, so I know it to be the most accurate info out there.


Cliff's notes:
'86-'98 8.8 housings are the same width @54.096"
'88-'88 TC 8.8 is also 54.096"
Again, this is the housing, NOT the axle to axle measurement

Now for the axles:
'86-93 Fox Stang axles (7.5 and 8.8)---29.18"
'94-'98 Mustang axles (7.5 and 8.8)----29.97"
and ALL Tbird/Cougar axles (7.5/8.8)--29.91"

This doesn't count the Ranger/Aerostar axles, which I left out, as they really pertain to Fox Mustang track width, and not the Tbird/Cougar. At least, not the '86-'88 cars, as they seem to be able to fit a wider axle, and/or tire combo without protrusion.

Believe me, I've studied the shiznit out of that chart...perhaps it's stickied in the axle tech section. ;)

OfficerJoseph, not that I'm cirtiquing your build or plans, but I'd rather have the proper length axles than spacers, plus, you can tailor in your planned brakes, or 4 vs. 5 lug at the same time..just food for thought. Make ya hungry? LOL :)

I understand most of what you said,

When I did my swap I retained the Mustang axles and just bolted up the 10" backing plates which fit just fine.

I would imagine then, that if you used Bird axles in the TC/Mustang rear that the drums would be sticking too far out and not mate up with the backing plates...

Hmmm, maybe you're onto something; when i did mine, I had put a small flat washer on every lug stud on one side (or the other, can't remember which, exactly) because the drum contacted the backing plate just enough to cause a noise. I'll have to mock the setup on the Mustang rear i have in my shop, using a TC axle, a Sport back plate and drum, and see for myself if you're concerns are warranted. Somewhere there's a different number, and I'm not sure if it's in the depth of the Crown Vic drum I have, the Sport's original drum, or there's a mistake on a measurement on that chart. I'll look for the chart here, and link you to it so you can compare too.

TC  8.8 axles are 30" EXACTLY. So 30 X2 =60 + app 3/4 for the cross shaft in the housing gives you app 60 3/4" drum to drum on a TC!!!

Just curious as to why it would have to be 83-85 specific backing plates?  The plate ITSELF is actually different as well?

My "lowly"  7.5 has the 10 inch drums straight from the factory.  I'm actually quite glad it does.  They're a good match to 11 inch brakes up front with the 73 mm caliper.

The drum hats are different on some 9" drums. one syard I occasionally go to keeps drums on a shelf from every car with notes what they are off of. ill have to see if I can get up there and see if they still have them. one had a really deep hat ontop and said 84 tbird on it.

No, I mean the 10's.  Post #8 in this thread caught my attention concerning this.....

Well, Paul, the axle lengths are the same, and the rear housing widths are different between the affected years, and with the brake drums possibly being the same throughout, that means (to MY thinking, anyway) that the backing plates would thus be of a different offset.

I suppose I should compare part numbers of the brake drums of the '83-'85 cars vs. the '86-'88 models before taking that as solid though. Stay tuned...

OK, so I compared the brake drums via oreilly's website...they're identical for both '84 AND '88, in regards to 10" rear. So since the overall housing length is a bit wider on the older years, it stands to reason that their backing plates would be different (with less "offset") than the '86-'88 year's backing plates, would be a little "deeper" to make up for the narrower housing, but yet the -to- width is the same throughout all years.

Does this sound accurate to you guys?


The sure way to know would be to physically compare the backing plates from the narrow '88 rear against the wider '84 rear. Unfortunately, I have no idea where to locate such an animal, as the backing plates aren't sold by parts stores.

If there is indeed a difference, you would HAVE to use the older back plates to do the 10" conversion on an 8.8 WITH 4 lug, but you HAVE to use the 1988 10" backing plates if you do this swap using an 8.8 and going to 5 lug, as I did.

And Vinnie, I'm sorry for wrecking your post...:D

Ford:  Reinventing the wheel all throughout the '80's.....

I'm having a hell of time trying to find an image of an '84 backing plate to compare to the '88's b. plate...maddening, to put it simply..

I can snap a pic of my backing plate when the car comes back from paint....

I just rebuilt what I had from scratch. Had to get it done. Keeping the drum brakes I have until I can find another turbo coupe set up in complete form then I'll go to discs.