Converting a small bearing 9 inch to a large

[JohnJohn]

Currie sells 9 inch large bearing tube ends for about $70 a pair. How hard can it be to cut the small bearing ends off and weld these on?
I have a portable ban saw I can use to cut the ends off, make sure they are true, bevel the ends, bolt the ends on to the new axles to keep things straight then tack weld to prevent bending before finish welding?

Do I need a $250 alignment bar jig to weld these on? After all its my trail rig but I don't want to do a bad job.

My goal is to convert it to a large bearing then install 35 spline axles and truss the housing. I do have a 240 volt Miller MIG to do the job.

Is it worth it or just I just pick up a large bearing housing.

 

[SteveL]

If you're gonna cut and weld it I would narrow a stronger fw housing instead of swapping the ends of an eb one. Especially if it's a trail rig

 

[JohnJohn]

Thanks Steve. I did not realize the full width housings were stronger. It would be easier to find one i would bet. Something to consider while i am brainstorming ideas.

 

[Apogee]

Yes, you need an alignment bar IMHO. I am mid-process of swapping F150 width axle under my EB, and while I had it apart, I checked the alignment of the factory ends...they were within 3/16" of true, give or take, so the housing was far from straight. The ends had some pitting and corrosion in the bearing bores, so I bought a new set from Quick Performance ($65/pair) and put together a plan. I did all of the truss work and spring pads first, since I knew that would pull the housing a bit, and it did as expected, then chopped off the old ends and welded the new ones in place with a Mittler Bros alignment bar.

Four big, heavy tacks at the quadrants, and then welded out opposing quadrants sequentially until done with a reasonably hot 3-phase dual-shield MIG welder. Removed the bar and the finished product ended up true to about 1/16" on the differential bearing center line. Shock mounts, brake line tabs, etc were all done after the fact during final mockup.

If you intend to shave the bottom for ground clearance, I'd do that prior to the ends as well. I opted to keep mine as is for the oil volume, but reserve the right to go back later and do it if needed. Now that the back brace is on it, I'm not sure it would move much, if at all, but why take the risk if you don't have to, right?

 

[SteveL]

Look for a fw where the slope from the center section goes out wider to the axle tubes like a 77 housing.

 

[vintage bronco]

Thanks Steve. I did not realize the full width housings were stronger. It would be easier to find one i would bet. Something to consider while i am brainstorming ideas.

I have a HD 77 rear Large bearing Rebuilt / Reconditioned end to end including large 76/77 rear brakes & you are fairly close to me I am in Maryland.

Barry

 

[Boss Hugg]

Here's my experience.

https://classicbroncos.com/forums/showthread.php?t=278857&highlight=narrowing

 

[Broncobowsher]

The stock housing isn't that great. Not horrible, but there are plenty of better choices. I've welded up cracks in multiple Bronco 9" housings. Usually the web where the tube mates to the center section on the front of the passenger side and the back cover will crack at the weld and start to leak. Even Ford went to the better housing in '77. Going to 35 spline axles in a stock housing just isn't a good match.

Yes, you can find a better full size housing, and cut/weld new ends on it. Move over shock mounts and spring perches, it will be better. Alignment matters. I would also look at new housings. I can't remember which vender it is, but one had new housings that were very well priced.

 

[DirtDonk]

Yeah, I have to shout out to our housings at this point. It's not a bad deal at $479 complete (with perches welded on at the proper angle for most lifts) and free shipping for now: https://www.wildhorses4x4.com/category/Bronco_Rear_Housing
That's for the Super-9 #8689 and, while not exactly inexpensive, it's not bad and saves you a lot of trouble finding a full size housing and cutting it down. Or scrounging junkyards and classifieds for a '77 EB housing which is the same HD center as the full-size and has the large bearing flange. And then you still don't have all the features of this one already made up. Fishmouth tube fitment, billet big bearing ends, EB-ready.
And no aligning tools to beg, borrow, rent or steal...;D

This one is new, straight, and basically ready to go for under $500.

Something to add to the list of choices anyway.

Paul

 

[DirtDonk]

Just FYI, one difference you'll note between the Super-9 and a stock truck housing is the 3" diameter tube instead of the older 3.25" tubes, for which the center section housings are no longer made.
But your existing u-bolts will fit and tighten down just fine. Even the 5/8" Extreme u-bolts we sell work sweet.

Add a skid plate to it (#8679 https://www.wildhorses4x4.com/category/Bronco_Rear_Housing) and it's pretty bomb-proof.

I suppose you could do some extra work too, by adding a drain plug, for the perfect mid-level budget rear end build.

Paul

 

[billtammy]

Hey paul that's a great idea. Can you use all the old parts (axles backing plates center section etc) and just buy big bearings if you already have 31 spline axles

 

[DirtDonk]

Pretty much. The bearings are the same, the axles and brake backing plates are paired up, but there are variations on the shape of the housing ends, so the backing plates for a small bearing housing or even a "medium" setup might not fit the full bore big housing ends.

Which brake backing plates do you have? And do you already have the axle shafts?
If you don't have axles yet, and happen to have one of the backing plates that won't fit (easily) you can buy complete brake kits for a '76/'77 (https://www.wildhorses4x4.com/product/Rear_Brake_Kit_New_7677yr/Bronco_Drum_Brake_Kits) and then just get the proper axles for a '76/'77.
This way you have all brake parts that fit the housing end (someone correct me if that's wrong), and axle flange offsets to match the brakes.

If you already have shafts, then maybe you'll get lucky with the backing plates. But it sounds like you have small bearing brakes, which would normally need too much trickery to make work on the large bearing ends.
And then you'd still have the (usually) 10" brakes instead of the larger 11's.

The nice thing about getting the '77 brakes is that they are the largest that were put on an EB from the factory. You get the same 11" diameter as the normal big brakes, but the extra width.

So, another option at least.

Paul

 

[DirtDonk]

Sorry billtammy, I knew you were not the OP but I was adding/mixing details that were mentioned in earlier posts about existing brake hardware and such.

But it still applies that it depends on what you have now, regarding what you can expect re-use.

Paul

 

[billtammy]

Thanks paul i'm not trying to hijack this thread but i'm sure others are curious too seeing how there are many more 66 to 75 axles than 76 77 and tires are getting bigger and bigger. Hence the need for stronger axles and housings.

 

[DirtDonk]

Definitely. Strength is good no matter what.
And just like electrical grounds and battery cables, more is better, and overkill is just enough!;D

Paul