Drive shaft replacement

[reno]

Hello all! New member here.

Recently got my hands on a 1990 bronco with the 302.
The U-joints on the drive shaft are really worn and it needs to be replaced. However, I'm being presented with about 3 different options from every website I've checked. I ordered one that was supposed to fit, and it's 26.xx inches in length. It's about, fully extended, and inch too short.
The other options are 28.xx, and 29.31 inches. It seems like the 29.31 would be the best option since I had to extend the 26 almost to the end of the splines to get it an inch away from the rear end.
I'm about 99% sure this has the E40D transmission.
My confusion is due to the websites saying the 26 is the right option when it clearly isn't. There's no big lift on it or anything like that.

Can anyone here give me some advice on which to get?

The original drive shaft is so worn that I can't get it to slide back to it's fully compressed length, but even it leads me to believe the 29.31 is the way to go..

TIA

 

[Motech]

Hello @reno , and welcome to the forum!

I see your profile says you're from Arkansas, but it doesn't say if you're near a big city or not. The reason I mention this is because every large city has a driveline specialty shop, and I have found them to be the absolute best value for situations like yours.

The last one I dealt with was exactly what you have, a telescopic driveline that was seized up and immovable. Furthermore, it had a really complicated constant velocity, dual joint type of connection that is notoriously difficult to service.

I took the shaft over to San Jose to a specialty drive shaft place I have been using for years, and they built me a new one for less than the cost it would have required for me to replace the joints alone on that complex system.

That was a Jeep Grand Cherokee, but I've also had this firm build custom driveshafts on Broncos that I have heavily modified, and many other custom jobs too, whether my own or customer's rigs. I don't use them often, but would guess I have used them over two dozen times in the last 3 decades. They make finding the right joint a "problem? No problem!" experience too as they have everything in stock, plus that ability to custom build a driveshaft for such a great price.

Check around, do a web search, or even call up a local 4x4 or hot rod shop and ask them who they use for their driveline builds. I'm sure you'll find somebody who will take care of it professionally and impeccably.

Good luck!

 

[reno]

Thanks!

Unfortunately I'm no less than 100 miles in any direction from a place like that.
Is that really my only option? It seems like just replacing a rear drive shaft shouldn't be such a problem. But, if that's the case, I'll seek one out and see what I can do to get it there.

 

[Motech]

Is that really my only option?

I'm sure you can service and repair yours. Just be patient and you'll get good input here. There are a lot of knowledgeable men here generous with their wisdom.

And use the search function. That's where the gold is buried!

 

[Tiha]

Interesting, I am trying to figure out how they are measuring. guess I haven't done a fixed yoke driveshaft in a long time.

But you have two now correct?

Compress them both all the way, or extend them both all the way and measure.

I would imagine you will be 2 or 3 inches off from original.

2" and you need the 28"
3' and you need the 29"

 

[reno]

Interesting, I am trying to figure out how they are measuring. guess I haven't done a fixed yoke driveshaft in a long time.

But you have two now correct?

Compress them both all the way, or extend them both all the way and measure.

I would imagine you will be 2 or 3 inches off from original.

2" and you need the 28"
3' and you need the 29"

I'm thinking the 29. Because I had to extend the 26 a ways and it still had an inch to go.

My understanding is that they are measuring the shaft only. Which really threw me off for a.minuye because the measurements I was looking at went from 33-36 to 26-29. It seems like some websites use the shaft length alone, and some use the measurements with the yokes. Also, the measurement is always with the shaft compressed.

I've pretty much settled in the 29 at this point. Going by how the 26 sat in there, that has to be the right length.

 

[Motech]

Measure yoke to yoke

 

[reno]

Measure yoke to yoke

Oh, I whole heartedly agree. But, when I look at the websites, they have 2 measurements. One that's the shaft length, and one that's yoke to yoke. They're in separate areas of the product specs, but they are definitely there. The one I bought was a 26 inch, which is 32 yoke to yoke. I'm starting to understand why this is confusing for folks just starting to work on these.

But, I'm looking forward to getting the rest of the things I need to fix finished up and having it work properly.

Also, did I just get lucky, or are power window gears a recurring issue with these?

 

[Motech]

Also, did I just get lucky, or are power window gears a recurring issue with these?

You mean the little nylon gears that get ground concave by the steel motor and/or regulator gear?



Yup, recurring issue, especially high failure rate with aftermarket replacement motor/regulator assemblies.

Dorman has the market cornered on these units, and they ensure future sales by manufacturing their units just differently enough that factory Ford regulators and motors are incompatible. Then when something breaks, you have to get another Dorman brand part, and it's often a frustrating lesson when you try to repeatedly install a remanufactured Ford component into the Chinese junk that is Dorman.

So if you do replace the worn gears, go with the kits Bronco Graveyard sells.

And with a nod to @johnnyreb , if a motor fails, resist the temptation of "new" aftermarket regulator/motor assemblies (they are VERY affordable) and source a reman original motor instead.

Cardone is about the only brand left offering them, and be warned: they don't really care how they box them, and often you'll get a left hand motor in a right hand box. They seem irreverently pleased with this, even warn of the likelihood in their product description!