Busted Rear End Flange - Help!

[Matthew3c]

I’ve busted what I think is the rear end flange / pinion yoke. It connects the drive shaft to the rear end at the u-joint. Can’t get the nut loose to remove. Could it be left handed threads? Any tips on how to break loose? Tried breaker bar and air impact!

 

[sykanr0ng]

Sometimes a picture really helps others understand what you need help with.

How to upload photos - Become a Contributor < link

 

[Apache Bronco]

How long is your breaker bar? You may need to slide an iron pipe over it to make it longer.
Google ford 9 inch pinion seal replacement.

 

[DirtDonk]

Hey Matthew. WElcome to classicbroncos!

Yeah, those things are buggers. I think the assembly torque is like 200+ lbs, so your breaker bar better be a big one.
But you said you tried an impact already? Is it a good one with lots of air power behind it? Or could it not have the capacity needed? If it's not a powerful one with more than 200 lbs available, you might still need a bigger breaker bar!

And you can call it a flange I suppose, but "yoke" is likely more appropriate because flange yokes are a different style than ours. Flanges are flat round plates that the driveshaft joints bolt to, while your style on the Bronco is just a standard yoke.

But we knew what you meant.
Like was said though, be good to see pics anyway 'cause we like to see what others are going through.

If you're not ready to shell out money just after your first post, you can use an online image hosting site and link it here, or you can e-mail me (or anyone with the yellow "contributor" beneath their name) and we can post it up for you.

Good luck.

Paul

 

[bax]

Not left handed threads. Set your emergency brake and get a big breaker bar. Better yet use it as an excuse to get a bigger impact or compressor.

 

[kancox]

I just replaced the pinion seal in my 67 and it took 235 ibs torque to remove nut. Replaced seal and retoqued to 235

 

[SteveL]

Careful not to change your pinion depth/gear pattern putting it back together. Some guys count turns taking off the nut so they can install the same. it might be worth pulling the 3rd menber and checking the backlash before running it.

 

[Matthew3c]

Thanks - Best Quality Aftermarket?

Thanks guys. It just took some serious pressure! Now, putting it back together... what is a high quality yoke, u joints, and maybe even drive shaft? Thought I’d upgrade it all while I had it apart.

 

[Matthew3c]

Thanks again guys! I upgraded to 'contributor' and added a photo to my original post at the top of the thread. Because I'm new to this, I would appreciate any info on the rear end... is it a 9"? anything else you can tell from the photo? Will add photos to my profile as well and maybe the garage once I figure out how that works...
Again, much thanks for the advice!

 

[nvrstuk]

Now.... why did it break?

Do you have the correct pinion angle? Do you have an antiwrap bar? Do you have soft rear leaf springs like a 3 1/2" suspension lift?

Just asking because it will keep happening over and over unless you fix the cause... unless this just happened to be a weak, one time yoke breakage...

Ask the guys that break them over and over... because they aren't limiting axle wrap...

 

[DirtDonk]

Yikes, nice breakage! That's an unusual spot to break too I think. Almost like there was some long-term fatigue first, then the catastrophic failure.
Of course, if you've got a torque-monster engine, 5:1 low-range Atlas, 40" tires and a heavy right foot, that might just be par-for-the-course action!

Thanks for becoming a contributor.

Paul

 

[DirtDonk]

Oh, and yes that's a Ford 9" rear end you got there.
The good thing about all Early Broncos coming with such a desirable differential is that they rarely get swapped out for something else. Most of us still have them under our rigs except the beasts that need still more beef in their diet, or have swapped in a Ford 8.8" for the brakes.

The stock axles were all 28 spline, with 31 and 35 spline axle shafts being available through the aftermarket.
There were two styles used on Broncos with "small bearing" or "big bearing" ends on them.
They were almost always accompanied by the smaller 10" diameter, or larger 11" diameter drum brakes as well.
Some other minor variations, but those are the main categories. There was a change in housing shape/design in '77 like the full-size trucks got. We also sell some very good large bearing and heavily reinforced housings for not too much money by today's standards: https://www.wildhorses4x4.com/category/Bronco_Rear_Housing
Should you ever need one.

Very strong and a huge number of gear choices. Some good yoke choices too, from mild to wild.
Here are some that we offer:
https://www.wildhorses4x4.com/category/s?keyword=pinion+yoke

Even a stock one at $70 bucks should last the life of the vehicle if it's not abused. So whether you just go with another stock one, or upgrade in material and size for about double that, depends on how you intend to use your truck.

Good luck.

Paul

 

[Matthew3c]

Thanks Paul!

Paul - thanks for all of the good info. I had already been researching your upgraded Yukon yokes. I’ll be in touch for sure!

 

[Broncobowsher]

That failure is almost guaranteed to be collateral damage. The U-joint will break one journal off and the other took out the yoke instead of breaking itself off.

Now why did the U-joint break? Looks like it had lube, what little I can see in the picture. So neglect probably isn't the issue. One thing they don't do is "just get old and fail". They will last nearly forever if taken care of. One of the big killers is axle wrap. I don't see lift blocks, but the tires look tall. Under hard acceleration the pinion is trying to climb the ring gear. This twists the axle housing in the springs, the front of the springs compress and the pinion rises. If it rises too much it can put the U-joint in a bind and that will break it. A good torque arm will take care of that. Keeps the U-joint pointing in the right direction under high torque conditions.

 

[nvrstuk]

Important to find the cause of this or it will just happen again... just a heads up...

Good luck

I know two guys that have broken 3 yokes before finally "fixing" the cause.