How much drive shaft angle is too much drive shaft angle?

[John_parkeriv]

Hey y'all, putting some finishing touches on my '66 before I can get out and play with it on my little one lane road and I've gotten to the drive shaft.

I've never lifted suspension or done swaps like this on any other vehicles, so this is all kind of new to me. Common Sense tells me that these drive shaft angles are way too aggressive.

I'm running a 351 windsor, m5r2 transmission, stock Dana 20, and stock Ford 9 in. 2.5 inches of lift on the suspension too.

I know there are other guys out there with the similar setup so what did y'all do to get it to work?

How much of an angle is too much angle, and what's a good way to reduce the angles?

 

[Yeller]

Yes you have driveshaft issues. You need a double cardan or CV (same piece different name) at the t case, this will require a new yolk. You will also need to shim the pinion angle to get the driveshaft and pinion within 2 degrees of each other.

Rear shaft should look something like this

The pinion angle needs to be at 1-2 degrees

Shims are available through a variety of different suppliers and multiple different angles. Be sure to get seep ones that bolt to the spring pack and do not just slide in, The slide in one’s break and cause lots of bad issues. The install between the axle housing and the spring pack, longer ubolts may be necessary as well. Here’s and example from Wild Horses

 

[Broncobowsher]

What they said.
I am also going to question that 2½" lift. Looks a lot more than that. That shock looks really topped out, I can see over the top of the tire, under the frame. The top of the rim looks to be nearly even with the bottom of the rocker panel. There is a massive looking add-a-leaf in the rear spring pack as well.

Being it looks like you are piecing together a Bronco from parts, you need to double check the yoke on the transfer case. The early ones use a now obsolete Borg Warner CV where the later ones use the still available Spicer CV. I know one of the Bronco venders had a great chart that showed the differences, I just don't remember which one it was.

 

[DirtDonk]

You have one of the rare (but not as rare as we once thought) single-cardan equipped '66 models. Is your front driveshaft the same design, with just two single u-joints?

I too say that's far more than 2.5" of lift looking there. Is your suspension extended, or are you on the ground? You need to put the full weight of the vehicle on the suspension before you know anything.
Before you change anything with the shaft, measure your suspension lift (with the full weight of the vehicle on the springs) between the top of the axle tubes and bottom of the frame rails.
Generally speaking, stock is considered to be 7" in the front and 6" in the rear. Give or take half an inch. Report back and lets see where you are sitting now.

Those big add-a-leaf kits were often for just 2.5 to 3" lifts. But the measurements will tell the story.

Paul

 

[CopperBronco]

I just got my pinion angle fixed… all to what they said above! Nashville Bronco does a little video on getting a baseline of your angle, so you know how much you need to shift the axle perches or shims to buy… but do what they said first… as a newbie myself when I lifted my Bronco last year I found Toms kits helpful to understand ripple effects. I’d highly recommend extended brake lines both for safety, but for when drooping the axle from the frame to get work done.

 

[CopperBronco]

Here’s link on how to measure angle while it’s on the ground…

 

[Broncobowsher]

Here’s link on how to measure angle while it’s on the ground…

He made a little mistake. No, not the shim backwards.
As the pinion goes up (from the shim) it also flattens out the driveshaft angle. Remember that the U-joint is rising from the ground, the transfer case isn't. So his 22° driveshaft angle is now something more like 20°.

Couple decades ago I did a quick lift at the same time I did an engine swap. Used springs that were sagged out so I added blocks to get the height. Had a lot of U-joint angle. My fix, got the blocks milled to fix the angle. And they were milled at the exact angle that I was off. I installed them and the U-joint angle was the wrong way. Over corrected. I learned my lesson. So far the YouTuber has not gone back and got a full set of current measurements to see what angle he is at now.

 

[CopperBronco]

He made a little mistake. No, not the shim backwards.
As the pinion goes up (from the shim) it also flattens out the driveshaft angle. Remember that the U-joint is rising from the ground, the transfer case isn't. So his 22° driveshaft angle is now something more like 20°.

Couple decades ago I did a quick lift at the same time I did an engine swap. Used springs that were sagged out so I added blocks to get the height. Had a lot of U-joint angle. My fix, got the blocks milled to fix the angle. And they were milled at the exact angle that I was off. I installed them and the U-joint angle was the wrong way. Over corrected. I learned my lesson. So far the YouTuber has not gone back and got a full set of current measurements to see what angle he is at now.

Yes, agreed! I measured mine, had 8 degrees angle after lift, then adjusted 6 degrees to get to 2… which I measured yesterday and was spot on, and driveline vibration around 40mph is now gone, but still have some at 50-60mph which I think is either driveshaft or tire balancing…

 

[John_parkeriv]

What they said.
I am also going to question that 2½" lift. Looks a lot more than that. That shock looks really topped out, I can see over the top of the tire, under the frame. The top of the rim looks to be nearly even with the bottom of the rocker panel. There is a massive looking add-a-leaf in the rear spring pack as well.

2.5" suspension, 2 inch body. The body lift is to clear the trans. The tires and shocks are still the original sizes at the moment.

 

[sprdv1]

Yes you have driveshaft issues. You need a double cardan or CV (same piece different name) at the t case, this will require a new yolk. You will also need to shim the pinion angle to get the driveshaft and pinion within 2 degrees of each other.

Rear shaft should look something like this
View attachment 886602
The pinion angle needs to be at 1-2 degrees
View attachment 886603
Shims are available through a variety of different suppliers and multiple different angles. Be sure to get seep ones that bolt to the spring pack and do not just slide in, The slide in one’s break and cause lots of bad issues. The install between the axle housing and the spring pack, longer ubolts may be necessary as well. Here’s and example from Wild Horses

good example sir.. definitely want the angle right

 

[Steve83]

Rear shaft should look something like this
View attachment 886602

But NOT exactly... That one is clearly busted. Angles should always be identical on each side of the double yoke. The Ford TSB on this page explains in detail:

(click this text)

 

[Yeller]

But NOT exactly... That one is clearly busted. Angles should always be identical on each side of the double yoke. The Ford TSB on this page explains in detail:

(click this text)

This link is correct if you do not have a CV at the tcase. If you do have a CV this doesn’t apply and the pinion/driveshaft relationship needs to be within 2 degrees. The angles that the OP is showing will never have happy ujoints without a CV at the tcase

 

[Steve83]

This link is correct if you do not have a CV at the tcase. If you do have a CV this doesn’t apply...

Yes, that page addresses the double-cardan joint (which is not a CV).

 

[DirtDonk]

Yes it is.
It is in fact the original constant velocity joint concept from at least a couple hundred years ago.
That’s how it was developed originally as a potential CV.

It did work, but was not as effective at it as the Rezeppa and other more modern models we’re more familiar with.

 

[jamesroney]

Yes, that page addresses the double-cardan joint (which is not a CV).

That may be the worst TSB that has ever been released. I'm not saying it's not factually accurate...but it has almost nothing to do with Early Broncos, and even less to do with Double Cardan type (NEAR Constant Velocity) joint applications.

Some very lazy engineer just cut and pasted the Dana Spicer application guide into a TSB and assigned it to a multitude of vehicles that exhibit offensive driveshaft harmonics. I've seen a lot of Broncos, but I've never seen one with a midship bearing. Yeah, Spicer calls it a "Center Bearing" but we all know that the "Center" bearing is that big ball located in the center of the CV joint, which we also all know is not true Constant Velocity. And we also all know that the Single Cardan joint is just a special application of the Hooke's Joint...and named LONG after both patentss expired so that we can give credit to different dead people.

OP, Do not be confused by the nomenclature. The Double Cardan type CV joint is NAMED a Constant Velocity Joint. It is not 100% constant velocity, and it does exhibit some angular acceleration. But that amount of angular acceleration is vastly less than what you get with a single Cardan, non-CV type Universal Joint. So while the CV joint in your Bronco is not truly CV, the entire industry calls it a CV joint. This type of inaccuracy drives some people crazy. But as long as you know what everyone is talking about, then the nomenclature is irrelevant. If you go to any driveshaft shop, or parts house, or wrecking yard and see one of those funky double u-joints on the end...it is going to be named a CV shaft.

Paul, I am going to disagree with the single cardan application on the 66 Bronco. Until someone shows me a Ford part number for a driveshaft, and a corresponding Ford part number for the special Yoke, and a corresponding part number for a rear axle assembly with different spring perches...I am going to call BS on the "factory single joint 1966 driveshaft." It would require a totally different BOM structure, and it would have to be built under a special DSO and there is no way that happens on the assembly line without some documentation. The transfer case yoke is on the BOM for the transfer case assembly, and it gets assembled days or weeks ahead of production. The assembly hardware is totally different. There is NO WAY that an assembly line operator can figure all of that out and get it installed in 90 seconds. That guy doesn't have a 1-1/8 inch socket within 1000 feet of where he is standing. In 1966, it is FAR more likely that a few aftermarket driveshaft repair shops figured out that you can use a 1310 yoke from the front of a Dana 18 on the back of the Dana 20 in the Bronco, and "fixed" a bunch of Broncos that way.

I suspect in 50 years, some specialty restoration shop for Ford Pickups is going to say: "Wow, another one of those rare 2022 F350's with the factory EGR and DPF delete feature..."

Gotta run.

 

[DirtDonk]

Nothing to disagree with James. Just that whether or not it was intended and planned, it actually happened.
Whether or not it's an official Ford thing or not is irrelevant (to an extent) because we know the Early Broncos were originally slated all along to have double-cardan shafts and both ends. Even the original frame mock-up for advertising purposes showed them clearly.

So I'm not going to argue with the different people who say their '66's came with single cardan shafts because I've seen them. At least two of which were absolutely still in the hands of their original owners who state categorically that they never had any work done on the drivetrain by the dealer or other entity. And here in these pics you can clearly tell if it's not original, it's certainly a very old conversion.
And of course over time anyone could have changed one out because they didn't like double-cardan shafts. Plenty of people like that out there and I've met them too. Used to work with a few!

Three of the units in question showed up at two consecutive year's of Jerry's parties a few years ago. Both of the latter were the original owners and a bunch of us crawled around underneath the Broncos.
I've been seeing single cardan Broncos for over thirty years now, with few two at the parties being over ten years ago now. Plus at least one at one of the WH Roundups.
And while I did not keep any info on the one that was at the Roundup, I saw it nevertheless. Can't unsee it...
However if I'm remembering correctly, that one was not the original owner. So no proof of anything.

Just like the never-before-heard-of and often unbelievable tale of the "Hybrid 30/44" (so named by me anyway) being found underneath Broncos from '68 to '70 and mostly of the '70 model year.
Now we take those axles for granted because more people have seen them and have found the BOM's and other documentation.
I have no idea why some few EB's got single-cardan jointed shafts under them, but I'm a believer because I've seen them and are pretty sure that the original owners were correct that nothing had been changed.

And here's another oddity that may or may not be related. A friend's '76 Ranger (now owned by WH) had it's entire rear end replaced under warranty in the first year of ownership.
That housing had it's perches welded on incorrectly for a double-cardan shaft and so he used to go through u-joints about every 5 to 10 thousand miles. Fixed by the installation of our 6 degree shims.
Perhaps the housing had been welded at the factory for a single cardan shaft. Or perhaps the perches were welded on by the installing dealer incorrectly because the tech was clueless about double-cardan geometry.
No way to know, but I always thought it was strange to have a factory supplied Bronco-only 9" housing put together incorrectly back in '76.

Now the one in this discussion is a good source of diagnosing. Why don't we look at the front end to see how the c-pads were welded on to get a correct pinion angle with radius arms. Is it correct, or is it set up for a double-cardan shaft?
Were the axles welded together incorrectly by Dana but, being in short supply, they decided right there at the assembly plant to change the yokes to single cardan?
What about the build date? If we can find more of these maybe we can find a similarity in when they were built at Ford.

Unfortunately I did not document build dates or anything about the VIN from the ones I've looked at.
Didn't thegreatjustino have one in his collection?

Paul

 

[TDubya]

Nothing to disagree with James. Just that whether or not it was intended and planned, it actually happened.
Whether or not it's an official Ford thing or not is irrelevant (to an extent) because we know the Early Broncos were originally slated all along to have double-cardan shafts and both ends. Even the original frame mock-up for advertising purposes showed them clearly.

So I'm not going to argue with the different people who say their '66's came with single cardan shafts because I've seen them. At least two of which were absolutely still in the hands of their original owners who state categorically that they never had any work done on the drivetrain by the dealer or other entity. And here in these pics you can clearly tell if it's not original, it's certainly a very old conversion.
And of course over time anyone could have changed one out because they didn't like double-cardan shafts. Plenty of people like that out there and I've met them too. Used to work with a few!

Three of the units in question showed up at two consecutive year's of Jerry's parties a few years ago. Both of the latter were the original owners and a bunch of us crawled around underneath the Broncos.
I've been seeing single cardan Broncos for over thirty years now, with few two at the parties being over ten years ago now. Plus at least one at one of the WH Roundups.
And while I did not keep any info on the one that was at the Roundup, I saw it nevertheless. Can't unsee it...
However if I'm remembering correctly, that one was not the original owner. So no proof of anything.

Just like the never-before-heard-of and often unbelievable tale of the "Hybrid 30/44" (so named by me anyway) being found underneath Broncos from '68 to '70 and mostly of the '70 model year.
Now we take those axles for granted because more people have seen them and have found the BOM's and other documentation.
I have no idea why some few EB's got single-cardan jointed shafts under them, but I'm a believer because I've seen them and are pretty sure that the original owners were correct that nothing had been changed.

And here's another oddity that may or may not be related. A friend's '76 Ranger (now owned by WH) had it's entire rear end replaced under warranty in the first year of ownership.
That housing had it's perches welded on incorrectly for a double-cardan shaft and so he used to go through u-joints about every 5 to 10 thousand miles. Fixed by the installation of our 6 degree shims.
Perhaps the housing had been welded at the factory for a single cardan shaft. Or perhaps the perches were welded on by the installing dealer incorrectly because the tech was clueless about double-cardan geometry.
No way to know, but I always thought it was strange to have a factory supplied Bronco-only 9" housing put together incorrectly back in '76.

Now the one in this discussion is a good source of diagnosing. Why don't we look at the front end to see how the c-pads were welded on to get a correct pinion angle with radius arms. Is it correct, or is it set up for a double-cardan shaft?
Were the axles welded together incorrectly by Dana but, being in short supply, they decided right there at the assembly plant to change the yokes to single cardan?
What about the build date? If we can find more of these maybe we can find a similarity in when they were built at Ford.

Unfortunately I did not document build dates or anything about the VIN from the ones I've looked at.
Didn't thegreatjustino have one in his collection?

Paul

Not the original owner, but my '69 has single cardans on both drivelines. It was originally sold as a govt vehicle, don't know if that makes any difference

 

[DirtDonk]

Don’t know either, but every bit of information is good.

 

[Steve83]

...the original constant velocity joint concept...

It might have been the original ATTEMPT at getting closer to CV, but it is not CV by any stretch. One U-joint creates angular velocity variations; the next one is phased & angled to try to cancel those out with its own variations. But 2 variations in angular velocity do not make constant velocity - they still create harmonic variations, but less-so than a single U-joint. It's just as reasonable to call a DC a CV as it would be to call a common driveshaft with a single U-joint at each end and parallel input/output a CV, since its intent is precisely the same as a DC. Neither is a CV. The Rzeppa design produces constant angular velocity at all of its working angles, and through each of its component pieces, so it's a CV (sometimes called "true CV" to distinguish it from NOT-CVs that some people refer to as CVs, like DCs).

That may be the worst TSB that has ever been released.
...
...assigned it to a multitude of vehicles that exhibit offensive driveshaft harmonics.

You don't seem to have read it, or its title. It is not supposed to be specific to any vehicle, or to any factory design. It was published to help dealer technicians working on ANY vehicle with MODIFIED suspension &/or driveshaft. And to that end, it's a very useful, worthwhile, informative, & valuable TSB. Some of those vehicles have a center bearing (which is not a centering ball of a DC), so the TSB addresses center bearings, too. Whether or not it was ever published before by any other company is irrelevant - Ford published (or re-published) it for Ford (dealership) employees. There's nothing "lazy" about that - Ford went to the extra effort of ensuring its dealer techs had access to the information, and that it would appear as a result when the normal dealer tech research was done on any of the vehicles that it might be expected to apply to.

...drives some people crazy.

Yep - some people get crazy enough about it to write several paragraphs. But I thought it would be enough to just say 5 words in parentheses.

 

[cldonley]

Not the original owner, but my '69 has single cardans on both drivelines. It was originally sold as a govt vehicle, don't know if that makes any difference

My 69 was the govenment vehicle style and had singles also. Whether factory or later change, who knows? I know that with the suspension lift double cardans became mandatory.