Front Drive shaft options The Eternity Build

[74 Bronco Billy]

I've been working on my Bronco for 4.10 years, and I hope to have it running in another month. YA! The Dash is almost painted and then I can start on wiring.

In the mean time, I have been picking away at some items and I found that the front original drive shaft is binding at the rear Cardan joint, closest to the D20 yoke. Yep, I've already broken off the zirc fitting in the U - joint that I got from Tom's. I replaced all the U joints awhile back.

SO, I measured out all the angles according to an old CB article and made a diagram (I think it is according to Tom Woods). I have angle issues I think. I'm not sure what FORD'S original angles were supposed be for the drive train, if you know, please share with me.

Lets start with what I have:
Wild Horses 3.5" Suspension Lift with a 1" Body lift as well. Original D44 modified to handle a F100 steering box mounted on the inside rail, with custom Tie rod over steering set up from Ruff Stuff. And a custom RAM. I measured the Caster today by putting an angle finder on the flat spot on the bottom of the lower bushing of the "C" knuckles and came up with 2.5 degrees. That seems exactly where I wanted the front end, and I like how the Drag Link and the track bar are almost parallel. Y, the pitman arm needs to be twisted just a little more, haven't heated it up to do that again, but I will get to it. The engine is in, so most ot the weight is in the Bronco, though it might squat some more with gas, roll cage, gear, myself, etc. That would decrease the angles I have now that are extreme.

Looking at the the diagram (driver's side), my Dana 20 sits 5 degrees down tilt toward the Ford 9" rear end. I have the rear axles perches cut off, so I can rotate the rear axle to whatever I need to for that perfect pinion angle. I have not set that up yet. But my main concern is that with the original front Drive shaft that I rebuilt with the universal joints from Tom's with zirc fittings, how do I go about decreasing the angle of the front yoke on the Dana 20? I'm binding on that 1st joint of the Cardan universal joint closest to D20, and I'm not at maximum droop yet.

I have those heavy duty motor mounts from Wild Horses, but they seem to be sitting in the lowest point of the frame motor mount saddles. Could I grind on those oval openings to lower the engine down an inch? Will the engine actually slide down the cradle more? Which would tilt the drive train down in the front, thus improving my angle off the D20 towards the Dana 44 and the front drive shaft? OR do I get the original motor mounts? do they ride lower, i.e., situate the motor lower in the cradle?

Or do I shim the transmission mount up? This seems counter productive as it would not change the angle of the drive train much, yet increase the height difference between the D20 and D44...I'm thinking not.

Or do I spin the pumpkin on the D44 upwards to achieve a better angle, yet it is only off by 10 degrees, will that improve it much? By spinning the yoke upwards, I decrease the difference in height between the D44 and D20, decrease the angle between the front drive shaft and the D44 (10 degrees down to what 5 or less), and I would think I decrease the angle (14 degrees) between the Front drive shaft and the Dana 20 front yoke. I don't like this idea because of all the fab I have completed on the D44 for my tie rod over set up with Ram assist steering, the custom track bar mount and lifted frame stops.

Or do I send all these readings down to Wild Horses or Tom Woods and ask for a high angle special front drive shaft that has extended radius angles due to their XC splines that allows greater articulation? Are these as strong as a regular set up?

Here's the real crux of the matter, is it a better design to rotate the pumpkin and hopefully get the angles within the original FORD tolerances for the front driveshaft, OR can I buy the high performance high angle front drive shaft and expect to be able to get the same performance out of it with those high angles?

More info: I'm running 4:56 gears in the axles, 36" tires, the original C4 transmission that has been built for the close to 400 hp I should be able to get out of my 5.0 roller with Sniper and trick flo heads. There's a good possibility I will be on granite slabs on the Rubicon since I live in that county. Original trac locs are in axles. And I like to go down the road at 65-70 mph, so I'd prefer not to have a noise or vibration from these guys. Might switch to an atlas later....

How good are those High angle front drive shafts, and am I in their tolerance range?

Does my front springs look ok to you? They have that characteristic bronco bulge. I am running 7 degree bushings in the radius arms. I've seen the adjustable radius arms that BC Broncos sells, but I think that if I used those to rotate the D44 axle I would improve my D44 yoke angle but cause a bigger problem of wrapping the the springs more and ruining the nice 2.5 degrees of caster that I have measured. And I would ruin all the connections for the RAM assist, the track bar mount, etc.

I'm pretty sure I put the "C" bushings in correctly, but I have included pictures (I mean, C'mon man, they say top on them). ;D;D;D

Please, any opinions from the advanced suspension front end guys is very appreciated. And thanks to all the guys that have helped me in the past come up with a steering geometry that should be bullet proof when done.

Forrest

 

[DirtDonk]

Hey Forrest, almost there! Hope you can make it to the Roundup this time WITH the Bronco. I may not be there this time myself (will be the first one I've missed if that's the case) but it would be great to hear you got the rig down there.

About the driveshaft, with all you've been doing, are you sure the suspension has settled down fully? If you measure between the top of the axle tubes and the bottom of the frame rails up front, do you come up with approx. 10-11 inches? If so, that's good.
If not, you need to compress it some more for your final readings.

The one C-bushing pic you have looks like it's in correctly.

The image of the side of the transfer case does look a little more tilted than normal, but I'm not looking at anything to compare it to, so wait for other opinions.
But how's about another front pinion pic, but directly from the side at u-joint level? This way we can see what the angle is on the differential, and if that's causing at least some of your issue.
Which it certainly can, with 7 degree bushings. Most have no trouble, but some will and you may be among that group.
Is this the original axle from your Bronco?

You can possibly get the engine to sit lower with a longer notch, but it might take spreading the frame at the same time since the mounts are already at the bottom of the V-notch when they're bolted and tightened. Might take some finesse then, and you don't want to put too much English on to the frame, but I don't think it would hurt anything.
Do you have an Explorer serpentine setup by any chance? If so you could run afoul of the front idler hitting the crossmember.
And what about clearance at the firewall and driver's side cylinder head? If there is plenty of clearance then the engine is probably not tilted down too much in the rear. Sorry I don't remember what the general degree of angle is supposed to be, but isn't there another discussion about this just from today or yesterday?

Bottom line is that if your front pinion is indeed pointed too far down, then pointing it back up will definitely reduce the angle on the upper joints. It'll give you a better angle on the shaft, but lower your caster which is not a good thing.
But since you can't actually know what your caster is right now, unless you did extensive measuring while putting it all together, then you won't know if losing some is a bad thing or a neutral thing.

That's about it for now. I'm sure others will add to the story later.

Paul

 

[74 Bronco Billy]

Hi Paul,

guess you're up late too. I will get another pic of front pinion tomorrow. But I think you misunderstood my one option, i.e., rotating the pumpkin WITHOUT rotating the axle by disassembling the axle tubes from the pumpkin. That way the pumpkin rotates up, but leaves all the nice geometry stable. Or at least that is how I was planning on doing it by grinding down the welds at the tube / pumpkin interface as carefully as possible, rotate, then weld back. But I have so many items attached now, I really don't want to go down that road if the high angle high performance front drive shaft will work.

No, there's just no way I can think I could get the BIG RED FRED to the round up, to many items to knock out as a business owner. And yes, missed you at the Swap meet last year. Hope to see you May 15th.

;D

 

[74 Bronco Billy]

I talked with Matt at Wild Horses and he came up with one more option. I plan to grind on the yoke that is hitting to relieve it so it does not interfere. The front drive shaft will only be used in slow speed situations, so, as long as we get clearance, it should be ok.
Jo at JB Custom Fab told me about some low rise zinc fittings, so I’ll replace the broken on with that. Once everything is put together, I’ll test maximum droop and if I still get interference, than I’ll talk to Tom Woods.
;D

 

[DirtDonk]

Yes, grinding is an option for some. Within a limited range at least.
But if you have to grind just to get the shaft to fit while sitting still, then I don't think there's much of a question that you'll need a lot more than that at full droop.
In other words, if it's binding now, there is no such thing as achieving a smooth full-droop without the joint binding.
It's a tried-and-true method of helping a tight fit, but what I'm saying is that I don't think you can reasonably grind enough off to have your cake and eat it too at this point.

Paul

 

[74 Bronco Billy]

Damn it Paul, quit using the common sense, you’re killing me. Time to call the good folks at Tom Woods and see what they think, full length splined.

 

[langester]

Glad to see you are almost at the finish line with your build, congrats!
I was looking at your pics and that angle on the t case looks funny to me. Do you have a pic of how the tcase is mounted to the bracket and the frame? What bushings are you using on the tcase as well?
Just curious to see what that looks like.

 

[DirtDonk]

Just pick one up at the Roundup! https://www.wildhorses4x4.com/product/High-Angle-Front-Drive-Shaft-Kit/Early_Bronco_Driveshafts ;D

But at least this gives you a pic of what you might get and need. Will they be able to build you one that fits your existing yokes, or will you have to replace yours with flange yokes like I suspect? Pretty sure that's the whole theme of the hi-dangle shafts using what started out as Toyota joints if I remember correctly.

But no matter what anyone says, and you may indeed need to go this route, STOP DESIGNING AND BUILDING (AND PAYING FOR!) YOUR DRIVESHAFTS UNTIL YOU'VE GOT THE REST OF THE ENGINEERING DIALED IN!!!!
There, now you've got my opinion on the matter.

Just saying that anything you do now with regard to either driveshaft could end up being 100% wasted time and money until you know for 1000% certain that your entire chassis is lined up and set up exactly how it should be.
Driveshafts seem like a soft target and easy get, but they are literally one of the last things you should be having built or worrying about in a custom vehicle build.

I know, you said stop using logic on you. But I can't help it. %)

Paul

 

[DirtDonk]

Ok, now that all of that is out of the way, yes I realize that you actually are almost done with the build, so it's not completely out of line to start working on driveshafts. But it seems to me that there are still a few remaining questions about the overall angles on stuff.
And did you verify the suspension height? Even though most of the weight is on, are you going to be adding anything else of substance? Maybe you said already and I already forgot? I'll re-read the last few pages when I get the chance, but in the meantime I wanted to slow it down until you were sure.

Paul

 

[sprdv1]

Damn it Paul, quit using the common sense, you’re killing me. Time to call the good folks at Tom Woods and see what they think, full length splined.

can't go wrong w/TW

 

[sprdv1]

It's a tried-and-true method of helping a tight fit, but what I'm saying is that I don't think you can reasonably grind enough off to have your cake and eat it too at this point.

yeah, for sure Don't grind it too damn much

 

[74 Bronco Billy]

Glad to see you are almost at the finish line with your build, congrats!
I was looking at your pics and that angle on the t case looks funny to me. Do you have a pic of how the tcase is mounted to the bracket and the frame? What bushings are you using on the tcase as well?
Just curious to see what that looks like.

Just pick one up at the Roundup! https://www.wildhorses4x4.com/product/High-Angle-Front-Drive-Shaft-Kit/Early_Bronco_Driveshafts ;D

But at least this gives you a pic of what you might get and need. Will they be able to build you one that fits your existing yokes, or will you have to replace yours with flange yokes like I suspect? Pretty sure that's the whole theme of the hi-dangle shafts using what started out as Toyota joints if I remember correctly.

But no matter what anyone says, and you may indeed need to go this route, STOP DESIGNING AND BUILDING (AND PAYING FOR!) YOUR DRIVESHAFTS UNTIL YOU'VE GOT THE REST OF THE ENGINEERING DIALED IN!!!!
There, now you've got my opinion on the matter.

Just saying that anything you do now with regard to either driveshaft could end up being 100% wasted time and money until you know for 1000% certain that your entire chassis is lined up and set up exactly how it should be.
Driveshafts seem like a soft target and easy get, but they are literally one of the last things you should be having built or worrying about in a custom vehicle build.

I know, you said stop using logic on you. But I can't help it. %)

Paul

Ok, now that all of that is out of the way, yes I realize that you actually are almost done with the build, so it's not completely out of line to start working on driveshafts. But it seems to me that there are still a few remaining questions about the overall angles on stuff.
And did you verify the suspension height? Even though most of the weight is on, are you going to be adding anything else of substance? Maybe you said already and I already forgot? I'll re-read the last few pages when I get the chance, but in the meantime I wanted to slow it down until you were sure.

Paul

What? Slow down the build Paul? It’s already at almost 5 years. We’ll probably be talking about it again next year, right?

Ok Langster, I’ll get you those pics, but ya, new trans bushings from WH. They can’t be put in upside down can they? And yes, the little rubber bumper is in place in front of Dana 20.

Paul, I agree on the grinding of the front drive shaft. Guess I’ll just leave the front drive shaft for awhile since yes, besides the parts mentioned earlier, I do have MIG’s heavy duty rear bumper to finish up and install, fabricate a front bumper, and install that huge Winch that is also a compressor I bought at the swap meet. And the hood, roll cage, top, back seat, door glass, window motors, wiper motors, etc, etc, etc. so, hey, brakes are on, I’ll slow down. ;D;D

Guess I better get that frame to axle distance measured, pics for Langster, and try and get motivated again. Damn it, it just takes so long sometimes. Especially when the sciatica hits like it did today. Ugh.

 

[Broncobowsher]

I think I see a flaw in the math. Front CV, that is a 26° operating angle, not 14.
Rear shaft length will change when you rotate the pinion up, it will also clean up the rear CV angle.

The angles on the front shaft are pretty fixed. it comes to a balance between good U-joint angles on the front shaft with bad road manors or good road manors with bad angles. That is until you start cutting and welding on the front axle. Either a high pinion 44 or cut the welds on the outer Cs and rotate for good caster while taking out the offset bushings to get a better front U-joint angle (which will help a little with the front CV angle).

 

[74 Bronco Billy]

I think I see a flaw in the math. Front CV, that is a 26° operating angle, not 14.
Rear shaft length will change when you rotate the pinion up, it will also clean up the rear CV angle.

The angles on the front shaft are pretty fixed. it comes to a balance between good U-joint angles on the front shaft with bad road manors or good road manors with bad angles. That is until you start cutting and welding on the front axle. Either a high pinion 44 or cut the welds on the outer Cs and rotate for good caster while taking out the offset bushings to get a better front U-joint angle (which will help a little with the front CV angle).

Oh CRAP, I think you’re right! I was wondering why it was so tight on that cardan compared to the front. Well dang. I really can’t do a knuckle turn as I have the knuckles where I want them and have already welded up the track bar riser, the RAM assist to the track bar, and installed the raised bump stops.

Has anyone done a rotation of just the differential in the center? Like disengage the tubes from the differential and rotate the differential up and then reweld in place? From what I can tell, I have the front alignment in a pretty good geometry now.

Paul’s right, I have a lot of weight to still put on, especially that heavy front bumper with winch. It may compress a full inch down or more. It’s making more sense

 

[DirtDonk]

Yes, the tubes have been freed and the pumpkin rotated up. Have not seen it done in years though, because most can get it close with bushings and most are also just trying to improve the caster more than they are the pinion angle, so most are cutting and turning the knuckles.
If you turned the whole thing to get caster ahead of time, this would explain the bad pinion angle.

Paul