Hello,
I'm wanting to do a rear disc brake swap into my '87 cougar. I have located a TC rearend from a '88 auto with the 3:73's. However, I am also wanting to do a 5 lug swap. From what I understand the Mark VII rearend and the cougars are the same in length. Is this true? It should be a direct bolt in. What is everyone's thoughts?
It'll bolt directly on but the Mk VII rear is wider by an inch and a half (3/4" per side)
Okay, now what your saying is the Cougar rearend is 1 1/2 wider than the mustangs and then you say the Mark VII is a 1 1/2 wider than the Cougars? I think i'm going to measure, because I have heard of the Mark VII rearend in mustangs.
NO the Mk7 rear end is 1" overall wider than the TBirds/Cougars....
Then how much wider is an '88 T-Bird rear over a Mustang rear?
Deja Vu anyone?
Yes.....this is the 6th time I've read the exact same questions this week.....
O.K.,I measures the Stang rear,and it looks to be 3/4 of an inch narrower than the T-Bird rear.
What measurment? Overall, or the housing only?
What Tbird rear?
From to on the axle shafts.The other rear (come to think of it) was from an '85 TC.
The '88 may be a tad wider.I have one of those out in the garage as well that I'll measure.
Ok, that seems right.
The 88 rear will have the same measurement from to on the axles as well....
Ooops. Sorry, my bad. I'm old and my brain sometimes slips into reverse. :hick:
This is by far the single most confusing topic I have ever seen. Somebody should make some kind of graph or chart or something with what is what for every year of all Fox and brake style. Or at least Bird/Cougar, Mustang, and Mark
There seems to be a difference of about (with my measuring) 1 3/4 inches between the Mustang rear and the '88 T-Bird rear.Now,how do I make up the difference when I install the Mustang rear into my '88 T-Bird?1/2 inch spacers and longer lug bolts?
Do you have the axles/brakes from the 85TC axle?
Double-check that the 85TC housing is the same as the 8.8 you have. If so, then swap the axles. brakes, etc from the 85TC rear end to the Mustang 8.8....
The braes on the 8.8 are 10 inch,and 9 inch on the TC rear.I may just add longer studs and get a couple of 1/2 inch spacers.I need my tires where they are supposed to be since I now have the 17x9,and would also like to keep my quad shocks.
Well 3/4" is the difference between the Mustang and the Tbird rear width, but 1/2" might work.
I've got the 10" T-Bird drums, backing plates, etc (in fact, the complete setup including fairly new shoes, springs and adjusters) from my 7.5 if ya want 'em. Shipping would be a bitch though - they're HEAVY
*EDIT* Never mind, I just noticed you have an '85 TC axle, which, if I understand correctly is shorter than my 88 7.5" axle (but the axle shafts are the same, making the difference up in the backing plates and drums). Of course, that's IF I understand this rear end silliness...
Yes, you understand correctly.
I was going to mention some 10" backing plates for the earlier cars, but I'm not sure if they're even able to be found.
Yeah,I have a two 7.5 Traction Lock '85 TC rears with 3.45 gears,an '88 T-Bird 7.5 rear with 2.73's (and a traction Lock '88 T-bird rear with 2.73's in the car now),and an 8.8 Stang rear with 3.55's.I have parts,believe me.I just want my tires to fit right in the car once I install the 8.8.So,what is your idea of how to do that?
Personally I wouldn't worry about the 10" drums and just swap the stuff from one of the 85TC rears into the 8.8.
The axle shafts from the 7.5 are longer than the Stangs,which will push the wheels back out,right?Keep the 9 inch brakes and call it a day?Sounds like a plan.
You're not listening are you? ;) :D Yes.
First, compare the width of the 85TC housing vs the Mustang 8.8. make sure they are the same (the changeover to the wider housing was late '85, so just to be safe).
The Tbird axles regardless of which housing (early 7.5, late 7.5, 8.8) are all the same length and are 3/4" longer than the Fox Mustangs.
Swap the 85TC axles and backing plates onto the Mustang 8.8 and that will give you the same width as what you have now with the 88 7.5 Tbird rear.
Also, as a homework assignment, since you have both an narrow and wide housing 7.5 there, can you measure the location of the bearing surface on an axle from each? I guess measure from the splined end out and then get a measurement of the bearing surface width?
I have to agree on the chart. Most of the hard-core Ford guys I know don't seem to know on these conversions.
I'll get measurement today from the of the axle shafts,and the axle housings and the bearing surfaces.I have all 3 rears ('85 TC 7.5 rear,'88 7.5 rear,and Stang 8.8 rear).I was looking at the Stang rear and it looks as though it has had two pieces cut from it.I'm wondering if it was a disc rear at one time.I really don't know.I didn't notice that when i picked it up.The guy I bought it from had it under his '86 Cougar,and said he pulled it from an '88 TC,but,the rear has 10 inch drums (it also has quad shocks).Anyway,I'll get measurements.
O.K.,here are the measurement that I came up with......
From bearing surface to bearing surface...
8.8 Mustang rear 54"
7.5 TC rear (1985) 54"
7.5 '88 T-Bird rear 56"
From axle to axle (wheel mounting surface)
8.8 Stang rear 59.5"
7.5 TC rear 61"
7.5 '88 Bird rear 61"
Those are the numbers I came up with.If anyone needs anymore info,I'll do my best.
Vinniebird
The differance in your Stang (Bearing to Bearing) and ( to ) is 5.5 inches
The differance in your others (Bearing to Bearing) and ( to ) is 7 inches
Wondering why the differance, Are the TC and 88 Rears both Disk Brake rears?
NO...does no one pay any attention to what I have been saying?
The 85TC 7.5 rear housing IS THE SAME AS THE MUSTANG HOUSINGS (7.5 and 8.8). The Tbird/Cougar USES LONGER AXLES.
The 86-88 TBird/Cougar 7.5 housing IS WIDER BUT USES THE SAME LENGTH AXLES AS THE 83-85 TBIRDS/COUGARS.
That is why the 85 has the same housing width as the Mustang and the same overall width as the 88 TBird.
Vinnie- When/if you can, pull an axle from the 85TC and the 88 TBird rear end and compare the location of the bearing surfaces.
Will do.I'll post the measurements here when I do.
Don't forget to add that crucial extra bit of confusion: 87-88 TC 8.8" disc brake rear housings are the same width as 87-93 Mustangs rears but have the longer T-Bird/Cougar axles, so the overall width is the same as all 83-88 Birds and Cats.
On a somewhat related note, when I put my 87 TC rear back together I used my old 7.5" axles because the TC ones were worn. They were identical length, but because the old axles didn't have the ABS rings on 'em they
looked like they were sticking out of the housing further. This was only an appearance, though, as the axles were the same length (I checked before installing). The brakes all went together fine though. The bearing surface was actually "shiny" right out to the end of the 7.5" axles, owing to the longer 7.5" housing - about 3/4" of this shininess is sticking out of the assembled rear now.
On the first part...I got tired of repeating myself for probably the 5th time this week...that's why I specified 7.5 housings.
So what you're saying on the bearing surface on your 86-88 7.5 axle is that it's in the same place on the inner location and extends further out onto the axle, and thus the bearing surface is wider?
To simplify things a bit, I have yet to hear of a differance between axels from 8.8 to 7.5 I beleve there 100% interchangable.
Then to mess it up, on some 8.8 31 spline falls into play... Cobra rears I beleve are 31 (ok, forget I said that :evilgrin: )
Again.....something else I have been saying for a while now......
I dunno about the actual bearing surfaces, since the axles showed no wear at all (which is why I used 'em), but the seal surfaces are definitely wider. The TC axles would not have gone into the 7.5" housing all the way because the ABS rings would prevent it (even without the backing plates installed). If I didn't already have the brakes on I'd snap a pic, but the shiny portion of the 7.5 extends almost to the point where the axle starts to widen into the - it's about 1/4" back from the . The ABS ring on the TC axles are about 3/4" thick and are pressed right up against the , and the shiny surfaces extend almost all the way to the abs ring (about 1/4" inboard from it). I actually do have a pic of the TC axle, attached below As you can see from this pic, though - the actual bearing surface (which is worn on this axle) is inboard just about as far as it can go before the axle starts to taper away from the machined surface.