Shorten front driveline myself

[68 Broncoholic]

I know it shouldn't be done but doesn't seem harmfull for a front shaft that doen't get ballanced anyway.
Here's my situation: I need to shorten my front shaft 1" after adding a longer slip yoke.
I grinded off the weld on the tube (slip yoke end). I pulled the pressed in piece off and noticed the wall thickness of the tube was very thin like .095 or less. My thoughts are to replace it with .120 wall which I have. To do this I would need to take both ends and have them milled down to the ID of the .120 wall so they can be pressed back in. The tough part is keeping everything straight when pressing in the ends to reduct future vibrations. I have a chop saw that cuts very accurately. I can see this is the crucial part so it gets pressed on straight. Anything else?

 

[Skuzzlebutt]

If it was me, I'd pull it apart and grind the male part an inch shorter.

 

[welndmn]

A lathe really helps to make sure its true.
Saying that, I have done many.
I normally just cut the old shaft, find a peice of pipe or tube (depending on the OD of the old shaft) and get a peice thats a tight fit, something I have to use my press to install.
Drill holes for plug welds, press it on, weld in plug welds, weld sleve to old shaft...... good enough.
I do get up to speed at the dunes and the snow but I am 90% rocks.

 

[68 Broncoholic]

So I simply cut the original tube in the center, take out the inch I need and sleeve the entire tube with a tight fitting thick wall tube, press until it stops, measure, plug weld a few places and weld the ends? Seems like a logical way of going about it but I already have one end taken apart. I could press it back in and weld it back up so I can do what you're talking about. Doing this I might have a problem getting my part pressed back in straight. I'll use a V block to help, wish I would have asked before grinding the end off. Lets hope I can find a tight fitting tube to go around what I have. Thanks!

 

[RajinCajun]

I have also done a few fronts myself by taking my time with a cut off wheel to cut the weld and pull the splined piece out of the tubing and the other end also. Then I get actual drive shaft tubing from the drive line shop and cut it to my needed length...tap the ends in place and weld them up. I am running 35" Boggers and have ABUSED the crap out of my front drive shaft, and my rear too which I extended as a temp thing since I was trailering my Bronco most of the time until I upgraded to power steering. My rear vibrated a little, but that was mostly from worn out splines...it didn't vibrate at all at first...I just got lucky I guess. But for a highway rig, I say let the experts do the work on your rear...on the front it isn't a problem if you drop a shaft..

I would say if you have a piece of tubing that will fit, use it. I did another one with some thicker tubing so we had to grind a little off the splined piece for it to fit and it is still going....

 

[68 Broncoholic]

Thats the way I was invisioning from the get go.
I have .120 wall tube that has a slightly smaller ID than whats on their now. If the two ends were spun down at a machine shop 1/16" or so they would fit the ID of my .120 tube.
Did you say you ground down the ends to make them fit into the tube?
How did you grind perfectly round so it fits into the tube nicely? Seems a lath is the only way to get agood pressed fit.

 

[SaddleUp]

I've shortened dozens of them and usually can even get away with it in the rear as well. I cut the end off by cutting the weld. At the same time I mark the location of any weights on it and remove them if they are at that end. Then I cut out what I need, shove the end back in and get it as square as possible (short of using a lathe and indicator) and weld it back together. I then add the weight back on in the same location. I don't get too concerned about the thickness. The only driveline that I have ever twisted the tube on was one where I substituted pipe and then sleeved it. (I still have the twisted off chunk around here somewhere) Therefore the only advantage I would see to thicker material is that it would be less prone to denting if it landed on a rock.

 

[blackbeauty]

Here is a cheap trick that might help. Install a hose clamp on the driveshaft and drive the vehicle to see if the vibration is better or worse. If it is better, weld a weight on where the screw was on the hose clamp. If it is worse, loosen and rotate and repeat. I would probably use a few clamps and mark the location so you have a reference point.

 

[68 Broncoholic]

So you think the thin tube is ok to use running 38's locked up?
I figure since I have the .120 wall tube I'd rather use it and its a close fit.
Does it matter if I use seamed tube (none DOM)? The existing has a weld seam so I don't see why not.

 

[broncnaz]

Your good with the way you are shortening it the only other thing I would worry about is keeping the yokes on both ends of the driveshaft in phase. ie you should be able to lay the drive shaft on its side with both yokes level on the surface its on. tube will not touch the surface.

 

[SaddleUp]

So you think the thin tube is ok to use running 38's locked up?
I figure since I have the .120 wall tube I'd rather use it and its a close fit.
Does it matter if I use seamed tube (none DOM)? The existing has a weld seam so I don't see why not.

Dom has a seam also. It's just harder to see it because it's drawn over a mandrel after it is welded. I would say the tubing thickness would probably be fine. (It will still be stronger than 1350 joints will) If you have the thicker tubing handy though then it shouldn't hurt to go ahead and use it and it will hold up better if it gets hit by a rock.

 

[SaddleUp]

Your good with the way you are shortening it the only other thing I would worry about is keeping the yokes on both ends of the driveshaft in phase. ie you should be able to lay the drive shaft on its side with both yokes level on the surface its on. tube will not touch the surface.

Yes. I forgot to mention I draw a line the length of the driveline including the ends so they are welded back on in the same position as they were before they are removed.

 

[Madgyver]

I've done it, Also lengthened the rear using the stock shafts. It's the balancing I can't do but so far no vibes at speed....

 

[RajinCajun]

Yes, I used a grinder and took my time on the yoke.. I used a square and took my time to make sure it was straight. It is the front shaft so I wasn't worried about it being 100% straight. I figured if I can get it 98% straight it wold be good... It has been going for over 2 years and taken some serious abuse... The tubing is DOM... a 3' piece was about $25.... I say go for it as long as you trust your welds...

 

[68 Broncoholic]

The tube I have is seamed 1/4" wide. Should I get some DOM or does it really matter for rotational load?
I know to align both ends. A flat surface to lay the yoke ears on while pressing the ends in should do the trick. I figure if I'm this far I might as well replace the thin wall tube.
Just flicking my finger on the side you can hear its thin. If I do the same to the rear shaft or any others I have laying around they sound much thicker.

 

[SaddleUp]

The tube I have is seamed 1/4" wide. Should I get some DOM or does it really matter for rotational load?
I know to align both ends. A flat surface to lay the yoke ears on while pressing the ends in should do the trick. I figure if I'm this far I might as well replace the thin wall tube.
Just flicking my finger on the side you can hear its thin. If I do the same to the rear shaft or any others I have laying around they sound much thicker.

If the end is off it then the sound when you flick it will be a lot different. Don't rely on just the flats on the ends to be sure they are square. That will get you close but you will still want to check it all of the way around. If I'm doing the splined end (Which I avoid if possible) then I will roll it across a flat surface and measure the distance in several places. I avoid that end because it is less forgiving if it isn't exactly straight.

 

[68 Broncoholic]

The spline end is the one I took off first :-X
I'll do the roll/measure check just before I weld.

When I was flicking my finger on the side of my drivelines all ends were together. The sound is close to a thin hand rail. The rest of mine sound close to a roll cage or thicker. I think the DS guys know I'll twist it and come back for a replacement. Why would they supply such thin material when they know I run 38's?

 

[67ster]

Part of my job is fabricating and repairing truck drivelines from 2" up to 4.500OD . Most the small ones are for PTO's for gigantic hydraulic pumps but use the same series weld yokes and spline plugs as the EB , I use 2" OD x .083" wall DOM which has an ID of 1.834" +-.005 , the yokes measure 1.845 +- .005 which gives a good press fit . After you determine the finished length cut the ends as square as possible use a combo square and a grinder if needed ( I use the lathe but grinding will suffice ) cut about a 30 deg. bevel on your tube joint and making sure the splines are indexed properly and then press the end in . I like about the wall thicknesses gap at the bottom of the joint for weld penetration . OK , to get this straight without a lathe or centers , use a pair of vee blocks and a dial indicator , you won't get it perfect as the tubing isn't always perfectly round but you'll get close enough , I shoot for +- .005 and the give the joint 4 tacks and weld it up . Sometimes the factory will use cardboard mailing tube material inside the tube to dampen noise , so tapping the OD isn't always an indicator of thickness. Even our largest trucks use only 4.5 x .234 wall and some of the 3.5" intermediate shafts are .134 wall .

 

[68 Broncoholic]

I have both a vee block and dial indicator. I'm going to get some DOM and not use the cheap seamed tube I have if I'm going to all this trouble. Only need 12" so it shouldn't cost much. A new yoke end to fit the new DOM tube is $30. Machine the spline end I have off now to fit the tube $20 and I do the rest.
Cheaper than the $200 I was quoted to have a driveline shop do it. I walked and he droped his price to $150 %) no way.

 

[blackbeauty]

Wow, $200 to shorten a driveshaft. I bought an all new cv driveshaft with long splined slip yoke for $200, delivered.
http://cgi.ebay.com/ebaymotors/JEEP...ewItemQQcategoryZ33738QQitemZ8032082494QQrdZ1