WARNING!!! LONG, TEDIOUS, HIGHLY TECHNICAL POST AHEAD!!!!


After a satisfying evening in the shop, I finally have some preliminary results to share. For anyone who may have missed this in the previous two threads, it had been mentioned that the '77-'79 T-bird, Cougar, LTD II, Ranchero, and '73-up Torinos all had the same 9" rearend and the books showed that the left side axle happened to be nearly the exact same length as both axles in the '57-'72 F-100 9" that most of us seek out to bolt in to our earlier '48-56's. The debate was to whether or not the T-bird style axle would drop in to the truck housing to give us a 4 1/2" lug pattern to match all the popular Chrysler, MII, and LTD front IFS swaps for our trucks without getting our old axles redrilled or the use of dangerous adapters. Dad's '77 Cougar rolled (barely) into the shop tonight for a desperately needed tune-up and I "borrowed" the left axle out of it to find out once and for all if this will work. Here is what I found out:

1. I am pleased to announce that the Cougar axle is almost a dead ringer for the truck axle with the obvious exception of the flange diameter and lug pattern. They are both 28 spline axles and they both have the exact same wheel bearing. The length difference is negligible. At worst, the Cougar axle would have to be ground just a hair on the splined end to eliminate interference with the spider shaft in the differential, but I'm not certain. It may even be a tad shorter. I will be taking better measurements in the next couple of days and I will post more specifics then. The axle diameter was checked with calipers at the bearing end and they are identical meaning that the original seals in the truck housing will work.

Noted difference: The pressed-on bearing retainer ring on the Cougar axle is thicker than the truck retainer. I honestly can't see where this would make any difference as even the thick retainer would not intrude into the seal area.

2. The truck axle retainer plate uses larger bolts (7/16" I think) to secure it through the backing plate to the axle housing. The Cougar uses smaller 5/16" bolts. (I think - note to self: Pay more attention to bolt sizes.) The bolt pattern is also different. The simple solution here would be to use the truck retainer on the Cougar axle. The bearing and bearing retainer ring must be removed to do this, but after 25 years, new wheel bearings ain't a bad thing anyway.

3. The use of the car's backing plates and brake drums to maintain proper brake offset and parts compatibility was also debated. As mentioned above, the car's axle retainers and backing plates are drilled for smaller bolts and in a slightly tighter bolt pattern. This precludes the use of the car's backing plates on the truck housing without major rework. Since the whole point of this exercise is to find an option for those of us who are too lazy to have our axles redrilled and would rather put something together with standard parts, major rework isn't likely to happen. The truck backing plates will have to be retained.

4. As for the brake assemblies, they are the same diameter on both vehicles, so this shouldn't be a problem. The wild card here is the brake drum. I had initially thought that the simple solution would be to just redrill the truck drums in between the original larger 5 1/2" pattern to 4 1/2" and be done with it since we have to keep the truck's backing plates anyway. That would maintain all the proper offsets and compatibility. On closer examination, I noticed that since the axle flange is a smaller diameter on the car axle, the original 5 1/2" bolt circle on the drum would come close to falling around the edge of the axle flange once the drum was installed over the studs. This looks too much like a weak link in the drum to attempt it in my opinion. As if that wasn't enough, the big center alignment "dowel" on the axle flange is roughly 1/2 inch larger in diameter on the truck axle than the car's. That would force the wheel studs to bear the responsibility of keeping the drum centered over the brake assembly. Not good.

So where I am at so far is that assuming we re-use the truck backing plates and axle retainer plates, the Cougar style axle will work if we can identify a brake drum with the correct dowel diameter, lug pattern, and offset. The Cougar drum may work, but I have not gotten far enough to find out for sure yet. If it does not, I guess we are back to scrouging for a suitable drum. I will keep you posted on the rest of my findings. The Cougar is ailing of a sick carburetor and serious ignition woes, so I will have the axle at my disposal for a few days should someone want a specific measurement.

Special thanks to Carl for pouring over the Hollander books for me!!!! We might need help again on the drum before this is over.

 

Joe

Thanks for all the hard work. It is appreciated. One minor point you may or may not have forgotten. All 57-72 F100s do not take the same brake shoe and drum. So it sounds like we don't have a one size fits all axle in any event. Not without machine work anyway. That is what we are trying to avoid here. You can redrill what you got if thats the cure for the Cougar axle.

Dewayne

 

Cool. Nice work, Joe.

I'll try to summarize what I've learned. Use the 57-72 axle housing, left side axles from certain mid-sized 70's cars, bearing retainers and brake backing plates from the 57-72 trucks, drums from the cars.

The potential hitch is whether the car drums mesh with the truck backing plates, an offset-type issue.

 

Paul or rage

What size brake shoes are on the F100 housing you are comparing to?

'fenders

 

That certainly was a LONG, TEDIOUS, HIGHLY TECHNICAL POST !!!


it was also extremely well documented, well presented and of infinite use to this group !!!


thanks Joe for all the work

john

BTW you might want to be a little more careful with that stuff...
your cool is starting to show

 

Good info Joe, just holler if you need me to ruin my eyes again.

 

All right Joe!
Searched the web and came across this (can't vouch for the accuracy). Select the '9 inch rear end info' tab:
http://www.ultrastang.com/Rearinfo.asp?Page_ID=1
One thing I took out of it is that our trucks are 'large axle bearing housing', identified by the 1/2" (3/4" socket) bearing retaining bolts on a 2-3/8"x 3.56" pattern. As far as the brakes go, most of the truck rears use 11"x1-3/4" shoes, and some use 11-1/32"x2-1/4" shoes. I wonder if you could use the '65-'67 Galaxy drums on the former and the 60's Tbird drums on the later? Maybe a Bendix or Wagner catalog could provide some additional leads?
Brett '59 F100

 

After yet another successful evening playing in the gear lube (two good nights in a row - this is scaring me), I have the rest of the story.

First of all, I lied in the preliminary post. Tonight, I actually installed the Cougar axle in my truck housing. As I had mentioned, the bearing retainer plates are drilled on a different bolt pattern, but I found that if I rotated the plate a bit, I could get two small bolts through diagonally and get the thing fastened together well enough to see how it all fits. I immediately noticed some interference when I tried to turn the axle. I initially thought that it was the end of the axle binding on the spider shaft in the differential, but realized when I pulled it out that it was the bearing retainer collar rubbing against the wheel seal in the housing. I pulled the seal out and put the axle back in and everything was just hunky dory. Remember when I said that I didn't think that the thicker retainer collar would make a difference? Well, it does. The seal in the truck housing sits outboard about 1/2" more than it does in the Cougar housing. That issue is solved easily enough, though. The collar will have to be split and destroyed to remove the bearing and bearing retainer plate. When reassembling with the truck retainer plate and a new bearing, just use a new smaller collar designed for the truck axle. The axle shaft diameter and bearing part number is the same, so it will be a simple replacement swap. I will get pics off both axles and the dimensions of the collars posted tomorrow evening.

Next, the drum. With the axle installed in the housing, the first logical thing to try was putting the Cougar's drum on. This is too easy, guys. It absolutely fits like it was built that way. The offset spacing and clearance to the truck's backing plate is perfect. I even measured to make sure that the shoes would contact the drum in the correct place. The shoes center in the drum exactly.

So, in conclusion, here are the final results. The left side only axleshaft and either side brake drum out of a '73-up Torino or '77-'79 T-Bird, Cougar, LTD II, or Ranchero will install easily in a '72 Ford F-100 9" axle housing on either side assuming that you use the truck housing's brake backing plates and brake assemblies, axle retainer plates, and bearing retainer collars. This swap nets the common 4 1/2" on 5 lug pattern with the truck housing.

I should also mention that all the above mentioned cars have 11" x 2 1/4" brake shoes as did my '72 F-100 axle. As, Dewayne mentioned above, some of the trucks had narrower brake shoes, so your mileage may vary on parts fitment on other '57-'72 housings. I can only vouch for my particular housing. A quick glance in an interchange manual should confirm whether or not your rearend has the same backing plates, bearings, and housing as mine. If you are palnning this swap and have not yet acquired the truck housing yet, I would strongly recommend getting a housing with 2 1/4" brakes and as close to the '72 model year as possible. It looks like this may be the 9" rearend for the vintage effie's that Henry built and never knew it.

I will get some pics and measurements of the bearing retainer collars posted tomorrow night. Good luck!

 

Batrage,

While I believe I was clear when I first mentioned this whole thing - that i was simply passing on folk lore, I am glad to see the info has proved true. That was a heck of a lot of work you went through. Thanks very much.

This brings two things to mind -

1. Much of the folk lore/legend relative to part swapping that I come across seems be dated. That is, it seems to involve parts/assys from 1960s and 1970s. There doesn't seem to be a lot of info floating around the net on parts adapting from the 1980s and 1990s. Nothing much you can do about this....just an observation....

2. You really should take all the notes on this subject and put it together into a single easy-to-follow tech article for easy of use by our brothers and anyone else that needs it. You would be doing us all a service. (And you just might end up becoming as famous as Niolon)
:-)

Regards,

 

rage

Thanks for pioneering this one for us. I am anxious to see what size brakes are on my truck. My axles are already drilled but this is still great information.

'fenders

 

As the guy who I believe started this debate, having a Volare front end with small bolt pattern and wanting same on 9 inch rear, I'll tell you what I did...only took 2 days...I had the axles and drums redrilled, new studs put in, to the small pattern for $75, by a local machinist who works on custom cars.

No bearing problems, backing plates, searching for axles, etc.
Worked for me. Next problem is getting the correct end for a driveshaft.

I guess that's another thread!


Paul

 

I did everything that BLUE OVAL RAGE and TRUCKFARMER said to do. Had to use small retainer to hold bearing, so it would not hit seal. Putting a small amount of grease on axle seal diameter and sliding the axle in place, I notice the seal rub on the bearing diameter instead of seal diameter. Everything esle worked ok. I use axles & drums out of 79 t-bird. I also have 2 1/4 shoes. I put 900 miles on truck since I change axles, everything is ok.

55peif

 

i have a 51 f1...with a volare 5x4.5...correct me if i'm wrong..
it looks like most of this info will work on mine also....
tks,jeepcat44