Double cardan delete?

Macrobb

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On my new 2000 F-250, looks like the double cardan joint is toast. Like melted metal "drips" have come out of the center section where the pivot and pin should be.

So, assuming the pin side(which is a part of the driveshaft itself) is bad... what are my options?
Looks like the 'right' thing is to just buy a new driveshaft.

I'm thinking of just converting it to a single U-joint up there by taking both "ends" of the double cardan joint, cutting the center sections out(leaving just the U-joint ears), and attaching them together with a single U-joint.

I will probably have to add a spacer to the t-case output to make up the length that I just lost with this mod, but it still seems cheaper than $250 for a new shaft.

This would leave a single U-joint at each end, which should be fine - it would make it like my '93 F-250 was from the factory.

Any really good reasons why *not* to do this?
 

SebastIDIan

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JY driveshaft? Seems like a lot of work to go backwards. Your time's got to be worth something. Just because you're not giving someone money doesn't mean its free
 

chillman88

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Any really good reasons why *not* to do this?

I know on the OBS trucks the F350 used the double cardan joint because of the driveshaft angle whereas the F250 didn't because of the slightly lower ride height. The issue was vibrations.

I don't know if that applies to the newer trucks but if you don't run around in 4wd much and are able to leave the hubs unlocked I don't see what it would hurt. I'd bet you'll know if it's an issue once you try it.
 

Thewespaul

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Manufacturers dont just spend the extra money to put spare parts in their trucks, if its a DC joint from the factory, theres definitely a reason for it to be there.
 

hce

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Replacing with a single joint may cause a vibration. The u joints in the double carden cancel each other eliptical path out since they are always at equal angles to each other. The single u joint on the stock shaft has no or little angle and does not need a mating u joint.
Problem with going to a single u joint on both end, is only one u joint will have an angle and its elliptical path will not be cancelled out, causing vibration.
Yank the driveshaft apart. It may be the replaceable ball that rides on the pin.
 

saburai

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Replacing with a single joint may cause a vibration. The u joints in the double carden cancel each other eliptical path out since they are always at equal angles to each other. The single u joint on the stock shaft has no or little angle and does not need a mating u joint.
Problem with going to a single u joint on both end, is only one u joint will have an angle and its elliptical path will not be cancelled out, causing vibration.
Yank the driveshaft apart. It may be the replaceable ball that rides on the pin.

Good possibility. That's what it was on my XJ. Eventually, I had Tom Woods build me a set of his excellent shafts - lifetime warranty on the u-joints...
 

u2slow

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When we did the D60 swap (with F350 leafs) in my buddy's '90 F250 IDI, he simply had the ttb driveshaft shortened and balanced. It was fine and didn't vibrate. It was more time & cost effective than trying to procure an F350 shaft and matching yoke for the t-case.
 

Macrobb

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You guys got me to thinking: What's different between 93 F250 and 2000 F250? Why the double cardan joint.

So, after grabbing an angle/level app on my phone, I measured that on my 93, the front axle is angled up at 6 degrees, the driveshaft is at 6 degrees(so right in line with the front pinion), and the t-case is angled about 3 degrees down, or about 9-10 degrees of total angle on the upper U-joint... which isn't being canceled out by anything!

On the 2000, the front axle is at more like 8 degrees, and the t-case more like 4-5. Not sure on driveshaft angle, but I'm guessing it's straight in line with the front axle. So now, I'd have 12-13 degrees of angle on the 1 U-joint.

It would probably vibrate a bit more at highway speeds, if I'm in 4x4.

So, plans:
1. Take driveshaft apart.
2. If fixable, fix it.
3. If not, try to get cheap JY shaft.
4. Plan D - make a spacer and call it good. Don't plan on using 4x4 at high speed.
 

greenskeeper

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What's the cab/bed configuration on your truck?

Anything shorter than a crew cab long bed you should be fine up to 90 mph with a single piece driveshaft.

http://a1driveshaft.com will set you up with a single piece shipped to you for about $270.

I went this route with both my trucks and never looked back.
 

YJMike92

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If you can't repair it yourself. find a local driveshaft shop and get it repaired.
 

Macrobb

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What's the cab/bed configuration on your truck?

Anything shorter than a crew cab long bed you should be fine up to 90 mph with a single piece driveshaft.

http://a1driveshaft.com will set you up with a single piece shipped to you for about $270.

I went this route with both my trucks and never looked back.
*front* driveshaft. So, cab/bed configuration is the same(engine/trans/tcase/axle is the only thing that matters).

If you can't repair it yourself. find a local driveshaft shop and get it repaired.
I've only got one shop within 50 miles of me that can do "driveline work". I say that in quotes, because while they can weld one up, they can't balance it. And when I had them make me a new one(for the rear of my '93), they managed to screw it up - one end was .020" off(T.I.R), and yes, it vibrated badly*. So, I'm not going back there.

(*I 'fixed' it by milling .020" off of one U-joint cap, and adding a spacer to the other side, such that the centerline of the driveshaft was now on center with the centerline of the U-joint, even though the yoke was off. It made a *huge* difference.)
 

YJMike92

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I've only got one shop within 50 miles of me that can do "driveline work". I say that in quotes, because while they can weld one up, they can't balance it. And when I had them make me a new one(for the rear of my '93), they managed to screw it up - one end was .020" off(T.I.R), and yes, it vibrated badly*. So, I'm not going back there.

(*I 'fixed' it by milling .020" off of one U-joint cap, and adding a spacer to the other side, such that the centerline of the driveshaft was now on center with the centerline of the U-joint, even though the yoke was off. It made a *huge* difference.)

There is always that problem.
I guess I should have said a "good" local driveshaft shop. It's getting harder and harder to find anyone who can fix things.
All the repair components are available online including the ones that weld to the shaft. I repaired my front driveshaft with spicer components.
 

Macrobb

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So... With the cardan joint totally melted, I figured I didn't have much to lose. I tried to press the old U-joints out, and just plain couldn't - not enough clearance.
Torch time! Hard to be tight when you are molten!
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Obviously toast - the only part I melted off is the U-joint.
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The other end - also pretty toast.
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Improved through the use of a portable bandsaw! Slow speed and it just ate through the hardened U-joints and cast steel cardan pieces
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Reassembled together. I think I trimmed a couple more bits off the corners of the 'ears', just for more angle clearance.

Oh, and I put it on the truck. It actually /fit/! It does seem to not have a lot of spline contact, so I'm going to make a 1" spacer or so and use that on the upper side, but it seems like it should work 'well enough' for now.
 

Macrobb

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Totally forgot about this thread. Someday, I'll get some good pictures of the spacer I made - it was like 4" in diameter, 3" long.

Anyway, it worked. Just fine. You can tell there's a little vibration when the hubs are locked in, but that may also be the shot wheel U-joints(which I still haven't fixed).
It's still a lot less vibration than my '93 with it's hubs locked. That, when you get up to about 65, you totally know it's locked and go "yeah, I should pull over and unlock them". This may also have something to do with the U-joints going south again...

I've used 4x4 quite a few times this winter, and been happy with it so far; hopefully this coming year I can get the time to do a complete rebuild on the wheel ends - new brakes, new manual locking hubs, and new U-joints at least.
 

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