rear axle shaft swap

[chermak79]

i have a 76 bronco big bearing 9" i am using and i broke a right side axle shaft...i have been combing bone yards with no luck....will a 66-75 big bearing axle shaft work in place of the 76-77 ones....from what im reading the only difference is the brake shoes are 1/2" wider on the 76-77 rear ends? will the early ones work???

 

[dsg40th]

I am not 100% sure but I'm almost positive the 76 and 77's use different axle flange offsets with the 11" x 2.25" brakes vs. the earlier 11"x1.75" and 10"x2.5" brakes which also differ from each other. The quickest solution is to buy new after market heavy duty shaft(s) for your application. Pretty sure the three different brake sizes used three different axle flange offsets to match the brake size.

 

[DirtDonk]

What dsg said chermak. While most of the big-bearing EB axles will "fit" into the housing just fine, the brake drum might not sit correctly on the shoes/backing plate. In your case, the drum might not even fully seat on the flange before it hits the backing plate.
It's not like most of the variations are huge, but they seem to be just enough to cause some headaches. It's hard to tell too, from other members experiences since it's hard to know sometimes what they started with, and what they ended up with.

With my '71 bb axle, I have a set of temporary 31 spline shortened axle shafts out of a full size rig. Not even close to letting the stock brake drum fit properly. The rear face sits out approx 1/2" from even covering the gap. Would a '77 drum close that gap? Yeah, probably, but what would the shoe/drum interface be like? I don't know and don't really feel like experimenting since I'm going to custom discs anyway.

And yeah, it's easy for me to say "buy aftermarket axles" because we sell them!;D But it's a legit option for not having to hunt for others any longer.
However, by that same token, unless you're wanting to upgrade to 31 splines now, you might just find some for sale here in the classifieds from others who've upgraded.
You could have my stock ones cheap, but they're early model and already on a friend's rig anyway!!!

Good luck.
If you can't find any good used ones, a new one is "only" $150 bucks plus shipping (http://www.wildhorses4x4.com/product/Heavy_Duty_Rear_Axle_7677yr_Lg_Bearing_11in_Drum_Right) so might still be a good option. Not many EB's in junkyards anymore after all. I'm thinking it's lucky you could even find some earlier models near you.

Paul

 

[DirtDonk]

Hmm, oddly enough, the temporary 31 spline axles I was talking about, are probably the proper offset for your '76 axle. Too bad they're 31's though, since you're only looking for a stocker 28 spline shaft.
Nice upgrade, but you'd have to replace the differential, or at least the side-gears in your existing one (if available) to let them work.

Oh well. Simple solutions aren't always simple!

Paul

 

[chermak79]

well i do have a 31 spline full spool i "could" use.....this rear end is in a 90 bronco 2 derby truck and my right side axle got broken....i might be able to put up with the brake differences because i would like to upgrade to a pinion brake set up anyway at some point..

 

[dave67fd]

This should help Id what you need.