12 bolt R.E. housing question--

[Greg Reimer 7376]

I just took a 12 bolt A body housing out of stock, cleaned it up, cut the OEM axle bearing ends off, painted it black, it's now ready for assembly. It seems to me that the bosses on each side where the bearing caps bolt on don't seem to be real large on the inside of the webbing in the center casting itself. I am putting in a new ring and pinion, new spool, all new bearings, axles a C clip eliminator kit, etc. etc, so the car is getting a good piece. My question is this-has anybody broken a housing at the carrier bearing cap webs? Not much chance with a 327 automatic N-O/SA type of thing, but did any of you high horsepower-stick car guys ever break one? Can't say I ever heard of one, but I thought I'd ask. Merry Christmas everybody,while we're at it.

[Mike Taylor 3601]

I never have saw one and I have broke about every driveline piece you can think of years ago,back when we thought the clutch should'nt slip any.
I have seen 9'' fords spit pinion out the front of center section.
Mike Taylor 3601

[Mark Markow]

only when the ring and pinion broke first.causing a cap to split. a girdle cover would help a bunch.

[SS Engine Guy]

Like others said, I have never seen a 12 bolt failure there that wasn't caused by something else coming apart first. Sounds like you are building a pretty good piece. On a hard leaving car I have the axle tubes replaced with thicker walled tubing to help keep the tubes straight. Even on lower powered stockers the tubes will bend and toe in the rear tires causing drag and drag from the axles not running perfectly straight. Any time I can't pull an axle out by hand or a very slight tap, I find that the tubes are bent and have to be pressed back into shape or replaced. Another good procedure is to replace the bearing caps with Mark Williams caps and good studs. This will require an align hone thru the new caps and housing. Also, if allowed, a good girdle with bolts pressing on the bearing caps is extra insurance. Don't tighten the bolts pressing on the caps tight as this can deform the caps. Snug with wrist pressure is all that is needed.
This may sound excessive, but over the years I have learned to overbuild and then don't worry about it. You will be way ahead later on down the line in terms of money spent and agravation. Also will be a small piece of the puzzle of how to make the car roll easier. ie: free up available hp.

[Robert Swartz]

Originally Posted by Mike Taylor 3601

I have seen 9'' fords spit pinion out the front of center section.
Mike Taylor 3601

Yep, did that with my D/MP Mustang in the 70's. 50lb flywheel with a good Hayes clutch. Twisted the driveshaft like a pop can and pulled the pinion right out of the the front of the carrier. Never have seen a 12 bolt do such a thing. I have them them break gears and split the rear cover. Have seen them spit out axles without having c-clip eliminators.

Have a good prepped 10 bolt for my my Firebird stocker. It's going to be an automatic car, haven't really been concerned about more bracing for it. It's had the tubes replaced, all the good internals. Have been considering a girdle.

[Greg Reimer 7376]

That's one part I forgot to mention. I have a pair of steel aftermarket caps with Allen head bolts for this thing, also the cover with the preload support bolts will be coming later. The caps date back to my 409 4 speed days. I'm sure this wagon won't be as brutal as that thing once was. Also,the axle tubes are welded into the center casting. Wouldn't it be great to get the center section casting reproduced, possibly with better metals and some further internal reinforcing? It would be necessary to offer two different castings-- the A body with the rear suspension bushing supports at the top, and the plain one for 65-70 big cars and all leaf spring applications. Also, the 8.5" 10 bolt is probably 90% the strength of a 12 bolt, so building one of those rear ends wouldn't be a bad deal,either.

[Alan Roehrich]

Greg, the 12 bolt is available in upgraded form from Mark Williams. The center section is improved, and the tubes are thicker as well. Not sure whether they're using the KTRE or the DTS housing.

[Dirk Olson]

I build my own stuff and what I do is first weld the tubes to the center section. I then cut the tube ends off and use a jig bar too align and weld the housing ends. Then I build a truss to keep the housing ends from pulling into its self, (if you don't do this it will bend). I also use MW caps on both sides. You need to grind the caps to fit, take your time this is important. Buy quality parts and stay away from the swap meet stuff.

[SS Engine Guy]

Dirk, u are exactly right. I forgot about the rods on the back of the tubes reinforcing the alxe tubes. I haven't used that but it should work. I think a manufacturer TA maybe, makes a set of tubes with heim joints that connect the axle tubes to the aluminum rear end cover.

[Mark Yacavone]

Yeah , I've ripped off the left hand cap on a couple of them.
Replacing both caps won't hurt anything ..
As stated , you have to mill the billet cap down to end up with the proper bore size and squeeze on the bearing race.
I did the brace deal on my Chevy II SS car about 30 years ago.
You want a left and right heim on the center link so you can preload the whole deal a bit.
Pretty sure I've seen them on Stocker now..
But NO heim ends allowed on strut rods, whatever you do!