This thread will be a how-to, and informational, with pics of progress and the results of experiments and trial and error, as it seems that nobody has really dug into this.
87thunderbirdblackjack and myself are independently working on this and sharing info via PM, I welcome his input to this thread as well :D:bowdown:
EDIT: this swap ONLY works using 1986, 1987, 1988 Thunderbird Sport 10" drum backing plates, SN95 axles, and 1988 Panther chassis (Crown Vic, Marquis) brake drums ONLY. There's NO known workaround for 4 lug, 10" drum swaps, UNLESS there are such a thing as a pre-'85 10" drum brake setup on a Tbird or Cougar. For a 4 lug 10" drum conversion you WILL need the backing plates from an '83 or '84 Thunderbird/Cougar...if such a brake combo exists. This I do not know.
Now, before we get started...no, I don't want discs, so don't say "grab some disc brake parts", because if I could find some for cheap, that weren't already junk, I'd already have the stuff in place and this thread wouldn't exist :D
Just in mocking up Sport 4 lug 10" drums onto TC length axles with Sport backing plates shows that the longer axles move the drums (and all the other brake components) away from the axle tube...meaning that spacers will need to be machined to properly center the backing plate, OR another avenue must be taken.
The reason I keep referring to the TC axle to mock up the placement is because the TC axle is the same length as the 5 lug stang axle I plan to use, so the length and distance between rear end housing and outer remains constant (or should be, in a perfect world) If in fact I can use the '85 10" drum backing plates on a '88 TC housing with Stang axles and the length is right, then I'll simply redrill my 4 lug drums into 5 lug and be one happy camper.
UPDATE: the Panther drums (Crown Vic, Grand Marquis, possibly Town Car?) drums seem to fit fine.
I sourced an '88 Grand Marquis 10" drum, and it's on a '97 Mustang axle (if you have axles from a GT, you WILL need to knock off the ABS exciter) and an '87-'88 TC rear. (Same as '87-'93 Stang 8.8 rear).
The backing plates are stock from my '88 Sport, as it had the 7.5 trac loc with the bigger rear brakes. Not sure what or where else to source workable backing plates from. Perhaps the Panther cars, assuming the axle ends are similar. (Most likely not, as I seem to recall gumby sating awhile back they are dis-similar in sizes)
I wanted to:
A; keep my stock rear track width,
B; avoid having to change master cylinder, brake booster, and get new park brake cables, and
C; 2 new drums are still less than the cost of ONE remanned rear caliper, and easier to find, to boot. You could probably find a set in the junkyard, but at least with new ones you're saved the hassle of possibly bad drums.
Anyway, here are pics with everything mocked up. It seems like there isn't enough gap between the drum and b/p, but keep in mind this is with the axle slid in as far as it will go. It will come back out about 1/16" or so with the c clip installed and the differential cross pin in place to hold things in place inside. Later today after I've slept, I will put that back together and put the axle back in it's proper spot and take a few more pics.
And to give credit where it's due, Clayton mentioned the possibility of the Panther drums...credit is ALL his. I just had a rear apart for the mock up...so many many thanks to you for the tip :bowdown::bowdown::bowdown::bowdown::bowdown:
here are pics (http://"http://s94.photobucket.com/albums/l110/fordtruckfreeek/vehicle%20pics/10%20inch%20rear%205%20lug%20drums/")
The "funky" rear is on the 85-88 7.5's. The housing is wider. The TC 8.8 and the early 7.5 housings are the same width. All the axles are the same length.
You'd want stuff from one of the 83-84 cars, but I never looked into the 10" drums on the 83-84 cars (I *think* they were available with 10" drums).
Modifying drums to 5-lug is pretty easy. Ran my 84 XR-7 like that for a bit after I swapped the 5-lug axles into the existing housing.
From what little research Ive done on the subject at the moment. I did check into those box body marquis/ ltd drums. Their drums out back come in 10" and 11" sizes. They are almost identical as to how they fit in the factory 10" tbird backing plates. The only thing that I am unaware of is size difference as in width wise. I might have to run up to advance with a tape measure here in a bit and get some dimentions for ya'll. But from a glance they dont have the flat drums we have. The center section where the axel meets drum is raised.
Alright enough of the BS Im bored Im going to run to advance and see what info I can dig up.
EDIT: I had my buddy at advance order me 2 drums one for a 88 grand marquis, and one for a 87 tbird both 10" drums they should be here Tuesday.
Ill get some measurements for us all Tuesday after work. So hang tight Beau
I would have taken mesurements for you off my 88 crown wagon. Anything you would like withough pulling the whole axle I might have to replace a bearing/seal on the drivers side too.
Personally though, I feel the early panther brakes are much larger.
Also, what about some of the 84-85 mark 7 ? I think they had drums on some. I've got a 7.5" rear out of a 84-85 mark 7 turbo deisel. It was setup for disks though.
Well I did some internet diggin. Tuesday Ill know for sure cause ill have the 2 sitting side by side. and have tangibility.
BUT I did find some numbers on autozoo's site.
The depth of a 88 marquis drum is just shy of 3.75
Center bore is 2.79"
Inner measurement is 10.0099
Outer measurement is 12.0078
Bird 10" drums are
Depth just shy of 3.5"
Center bore 2.75"
Inner measurement 10.09
Outer measurement 11.65"
I'm going to pull my wheel and take some mesurements. My drums looked to be flat on the side.
It'd be appreciated bub
(http://i33.photobucket.com/albums/d82/bosenKevin_02/2012-06-23160522.jpg)
(http://i33.photobucket.com/albums/d82/bosenKevin_02/2012-06-23160655.jpg)
(http://i33.photobucket.com/albums/d82/bosenKevin_02/2012-06-23160445.jpg)
(http://i33.photobucket.com/albums/d82/bosenKevin_02/2012-06-23160413.jpg)
(http://i33.photobucket.com/albums/d82/bosenKevin_02/2012-06-23160629.jpg)
(http://i33.photobucket.com/albums/d82/bosenKevin_02/2012-06-23160300.jpg)
Inner diameter is 11" for the drum. Outer is just shy of 12 3/4"
Center hum, I would guess to be 2 3/4" outside diameter.
Where the brakeshiznit is about 2 1/2"
Drum is 3 7/8" deep.
Backing plat stick behind drup about 1/4".
Any other pictures or mesurments you might need, let me know. I'm going to leave it off for a bit.
I guess I have. A bad wheel bearing and axle seal. I noticed yesterday I had a puddle by the tire. I thought it was the brake line, but my brake fluid is fine. I've had a slight noise, which I decided after taking off the wheel, my wheeel is rubbing the inside frame rail.
Also, according to the axle tag, I have locking 3.55 gears. No wonder my gas mileage is cruddy compared to my birds/cats.
I just realized your looking for 10" so my mesurements are basically useless. I guess the wagon (which had the heavy duty/taxi/police suspension package) had upgraded rear brakes and towing package. I didn't think you could fit over 12" of brakes behind a 15" rim.
According to my measurements... Everything SHOULD work. the overall difference in the width from hub to lip is 1/4 of an inch. By beau's pictures in a previous thread it looked like that was all he needed to be comfy.
The 88 grand marquis 10" rotor measures// 87 tbird 10" drum
Center bore 2 3/4" // 2 1/2"
Hub center to table flat 3 5/8" // 3 3/8"
pad surface 3" // 2 1/4"
the BP lip is 11/16" on both
Over all width 3 3/4" // 3 1/2"
I thinspooges I found a solution.
Nice! I was wondering if I should go get a Marquis drum and a Ranger drum, and just mock them each up and see how things look...I just might later today. Stay tuned.
(http://i18.photobucket.com/albums/b150/Tcj429/0626021046.jpg)
Lemme guess, ranger left, panther right?
There is a huge lip that I guess acts as a heatsink all the way around my 11" brakes.
tbird on left 10" marquis on right the lips are the exact same size depth and everything
Mine will be in tomorrow afternoon. Hopefully I can test fit the setup and see what the results are...
Clayton, you have a TC rear and SN95 Stang axles, same as I do, correct?
The other option I thought about was the Ranger 10" drum, because of it being a hair deeper, maybe it would make up the difference in the offset of the backing plate. I'll have a better idea once I test the Panther car drum though.
Yessir. I have a TC axel and SN shafts. I hope it works so I know what route im going. I cant quite tear apart my rear diff to convert over cause the car has to stay mobile for the time being. But if it didnt have to move I'd be on it already haha.
I'll have the answer we seek this time tomorrow :)
(with pics)
Sounds like a dealio. I hope my measurements are up to snuff. I'd really like to see them work im about 95% sure that theyre right. but that other 5% says no way!
Never have doubt
Well, the verdict is in.
Panther drums will work.
For the record, this was Clayton's idea, he was kind enough to share, and he didn't want to tear his rear apart to test it, and since mine was already...well...as they say, the proof is in the pudding, so without further ado:
to big?
No sir, my back plate wasn't tight against the housing the first time I checked it...and I'm tired lol.
I caught it the second time though..Houston, we are a go for launch sequence.
PS, haystack, if and when you pull your rear to change the bearing and seals....could you do me a HUGE favor?
Could you measure the distance from the centers of the backing plate bolts side to side, and up and down, and could you also try to get an accurate as possible measurement of the depth of the backing plate? I'm curious to know it the Panther cars back plates will bolt to and be compatible with a Stang/TC 8.8 rear. Might be possible to locate and package up 5 lug, 10" drum brake setups if there was a decent amount the proper width backing plates to use. So far, nearly as I can tell, ONLY the '85-'88 7.5 rears with 10" drums will have these correct plates.
Class dismissed :)
EDIT: just noticed the first page lol my bad.
Im glad it worked out!
I would still measure the housing (esp on an 85) to make sure that it's the proper width one.
Will do Chuck, if I come across that year somewhere/sometime.
Clayton...my drum is different than yours...I just realized it. I'll snap a pic of the lip, mine has a has a groove where yours has a lip. I ordered an '88 Grand Marq drum...I'll get the receipt and part number in a few. Mine's from Oreillys...I know you said something about autozone..so that may be it...stay tuned. :)
Thats odd. they should fit the same though.
A bit late, but here's the drum pic:

The rear is out, I need to clean inside the diff a bit, that can wait till in the morning when I'm home from work, as I'm off the night of the 4th. So I will try to get it all back together again before the weekend. Stopped by Oreilly, they still didn't have the other drum in, hopefully tomorrow...
I already had my axle done before I saw your response. I should be putting some new tires on in the next week or two. If I don't have to remove the brake hardware, I'll see if I can get the back plate mounting mesurements for you.
Cool, no worries. Whatever you can get, I'd appreciate :)
The rear is in, bolted tight, yadda yadda. Started the engine, put the trans in first, let it spin the diff for a couple of minutes. Everything seems to work fine, so I guess it's time to find some coin for new tires in 16". I'd LOVE some 315/45's, but I don't see a money tree in my pea patch.
Think I'm going to take a break from the Bird for a few weeks, I've got a *gasp* Chevy truck to strip down and swap the powertrain into my 4x4. Be a nice upgrade to a 350 from that gutless hunk of sh*t 305. Oil leaking, coolant burning hunk of sh*t.
In the meantime, I'll see if I can scare up motivation to get the interior parts....well, back in the interior of the Bird. Meaning, dash in, wiring, etc. One fire was enough, back to original stuff and cross my fingers. One more cloud of smoke, and I'm done with it.
SO the verdict is cheap 5lug route for those not wantion to convert to rear discs with 10" drums is:
1.)TC/ GT Stang 11" Spindles and Mark VII Rotors
A.) SN95 Spindles+ Rotors
2.) SN95 axels with ABS exciters removed
A.) 1988 Grand Marquis 10" Drums and factory 10" backing plates
Sounds pretty darn nice to me.
Yup!