1969 bronco axle swap/diff conversion

[Justheretogetweird]

I’m sure there’s a thread devoted to this somewhere….
I have a ‘69 bronco that is original with uncut fenders and I definitely want to keep it that way. It came with a bunch of extra parts. Most noticeably a front end and rear end matched gearing from what I can only assume is an F150. Everything to do a front disc conversion and they said the front diff was smoked.
Started with the rear end diff swap but my bronco had a small bearing rear end so the original 28 spline axles won’t work with the new diff and the larger 31 spline axles are too long.
If the rear end is doing this obviously the front end will too. What are my options here.
Thanks in advance for any help on this!

 

[DirtDonk]

So the bad differential is the front one that’s currently installed in your bronco? Or the new one that’s included?
And don’t assume they’re from an F150. Take some actual measurements.
Because in my opinion, upgraded axles, or not, if you want to keep your fenders uncut and use smaller tires, then you don’t want to start messing with wider than stock axles.
Just my opinion, but to me it would ruin the look and be more work than it’s worth because you’re not out looking for a wheel travel off-road.
And stability on the road doesn’t even come into the equation trying to keep the tires tucked under the fenders.

A matched gear set of full-size axles could be worth enough money to help you fix your existing differential. If that’s the one that’s bad.
And a bad front differential doesn’t keep you from driving on the street anyway.

You should always do your own testing rather than trust to a PO’s memory. Unless they were very detailed when they spoke to you, you might as well find out what’s wrong first.

 

[thegreatjustino]

It sounds to me like you're simply changing the third member out in the rear end. That way you keep the correct width housing but upgrade the gearing. If that's correct, you simply need to buy a set of aftermarket 31 spline small bearing axles from one of the vendors and they'll bolt right in.

As for the front, if you're attempting to do the same thing with the gearing, odds are that front end is high pinion and has reverse cut gears. Those won't work in your EB front housing. If your '69 Bronco still has the stock Dana 30 front end, the Dana 44 gears from the 150 wouldn't work even if they weren't reverse cut.