Spare Drive Shaft Build aka My Total Hack Job

A while back I broke the rear leaf springs on my rig and needed to replace them. I happened to notice after the new springs were installed that my rear drive shaft looked a bit short. It has a ton of compression available, but it only has about 2-3" of extension before it will pull apart. It was already like this (I didn't lift the truck any more than it was already) but somehow I never noticed it being too short.

I decided I needed a spare shaft in case I break the current one. I've gone through a few in the last couple years, so there's no doubt that this one will get beat at some point.
Here's the beater with the new 3" rear springs installed:


So, on to building the spare...

A dude broke his at last year's East Coast 4Runner Jamboree, so I gave him my old spare and brought home his broken one:


Then I cut out the really bent/twisted/broken section:


I did some measuring (cruising around Lowes with my digital caliper) and found that the ID of my shaft was just a freakin' hair bigger than the OD of 2" rigid conduit, so I picked up 10' of conduit for like $34:


I decided how long I needed my shaft to be and I cut the conduit to length, and slipped it in:




The broken shaft is about .050" wall, and the conduit is about .150" (kinda hard to tell the real difference 'cause I didn't file the conduit clean inside after cutting it with the chop saw). Where the new shaft is sleeved, it's nearly .25" thick:


I drilled some holes so that I could plug weld the sleeves together:




Since the conduit is galvanized, I ground it all off in the weld area:


Then I clamped it up in a homemade jig, using my bed rail and some 3/16" angle iron, so I could align the yokes/u-joints as closely as possible:




Once clamped up and as straight as possible, I tacked it in place, checked it again, and fully welded it. Sure it's not balanced, but it'll get me off the trail and/or get me home. I didn't get a fully welded pic, but it pretty much looks like this...

Might want to "spin" that thing and see how it is balanced. You could get one heck of a vibration going.

From my experience, you should have at least lined up the two yokes to try and get them in phase. Other than that, if it gets you out of the middle of the woods, nice job. I usually like to find little stuff like this to keep me busy on the weekends.

WVU Tuba Dale said:

From my experience, you should have at least lined up the two yokes to try and get them in phase.

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Yep, they're lined up. Look at the pic of it clamped to my bed rail. In that pic they look just a bit off, but they are lined up. I think shadows/dirt/grease on the right side make that one look crooked. The bottom pic they're not lined up, but that's before I welded it.

Yeah, I'm sure it will wobble pretty good, but it's just an emergency spare. The one I have in the truck right now is a bit bent already, but doesn't wobble too bad.

You can take it to an electric motor repair shop, they have the ability and equipment to balance it. Only takes a few minutes, I used to do it all the time for people bringing in drive shafts for machinery and trucks. Just a thought. If it is only a spare to get you out if yours breaks that is fine, I have seen them made out of square stock for that purpose as well.

did pretty much the same thing for a friends lifted jeep on 35's with 400+ HP smallblock with a bent front driveshaft, used some black pipe we had laying around, welded it all up 3 years ago, it's street driven, pulls hay wagons with it on the farm and wheels it. he has no idea that the shaft aint balanced, ir that it's a piece of black pipe, he's never complained about any vibration

I know lots of people who made front driveshafts, no balance issues lower speeds, I dind't ask if they had driven in 4wd at higher speeds.

Jared said:

I know lots of people who made front driveshafts, no balance issues lower speeds, I dind't ask if they had driven in 4wd at higher speeds.

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friend of mine has black pipe for both driveshafts, after he twisted his last good shaft in his amc360 powered jeep, he built a set out of pipe.
next time out he submerged it, and bent 3 rods before he got it shut off.

back to the drawing board, he dropped in a 4 cyl toyota diesel ( from a forklift) added propane injection, plumbed in a turbo from a volvo. the thing rattles and smokes, he takes him everywhere he wants to go

zer01 said:

I have seen them made out of square stock for that purpose as well.

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Yep, you can't really tell from the pictures, but my front is made of square receiver hitch tubing.

Jared said:

I know lots of people who made front driveshafts, no balance issues lower speeds, I dind't ask if they had driven in 4wd at higher speeds.

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My pile of **** never sees more than about 20 mph in 4wd, so my square, unbalanced, sloppy front drive shaft doesn't really cause any problems.


When there's a bad winter storm forecast around here, all my coworkers are like, "I know you'll be here, you have that truck you can drive." It's hard to explain to them that I can't really drive it in 4wd above about 15 or 20 MPH so, despite 37" tires, I probably won't drive it to work if storms.

I've done it. If they're fairly straight, you can "balance" them on your own. I just ziptie a washer stack to the driveshaft, take it out in 4wd and try it. Keep moving it until it gets the best, then weld a few washers to it. Keep adding weld/washers until it smooths out the best.

Sure it's ghetto, but I've had them where you can run down the highway in 4wd with no vibration.

nissan_crawler said:

I've done it. If they're fairly straight, you can "balance" them on your own. I just ziptie a washer stack to the driveshaft, take it out in 4wd and try it. Keep moving it until it gets the best, then weld a few washers to it. Keep adding weld/washers until it smooths out the best.

Sure it's ghetto, but I've had them where you can run down the highway in 4wd with no vibration.

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hose clamps work well for this, just the weight of the screw can balance it.

Don't make the driveshaft too strong. When in a stress situation something got to snap. A cheap part is best.

Nive work. But I would be afraid of the conduit twisting very easily. Is it seamed conduit or extruded? I'm thinking it is seamed which will allow for a weak area. I understand that it is an "emergency driveshaft, but you may want to make up a few out of DOM tubing instead.

My minute understanding of driveshafts is that they(the yokes) must be 90 degrees out to cancel vibration of other end ( in addition to the balance portion.) In order words, one set of yokes at 12/6 O'clock, and other end at 9/3 O'clock to cancel (or allow) flex.

scopx said:

My minute understanding of driveshafts is that they(the yokes) must be 90 degrees out to cancel vibration of other end ( in addition to the balance portion.) In order words, one set of yokes at 12/6 O'clock, and other end at 9/3 O'clock to cancel (or allow) flex.

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Uh.... nope. They need to be "in phase"....

ausome job........as long it spinns the wheels an mud flies its all good

i love how your not all worried about how it looks

nolatoolguy said:

i love how your not all worried about how it looks

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Well, you know, look at the truck I was putting it in.


Perfect timing that you bumped this thread. As noted above, drive shaft I had in the truck was too short (it was built for a friend's truck, but since both our trucks are hacked up our wheelbases are slightly different). So there wasn't enough spline engagement on the shaft I was running and I had a ton of wobble/vibration coming from it.

I swapped in this cobbled-together hack job last Saturday and the truck rolls down the road WAAAAAYYYYYY smoother than before. I'll keep the short one as a spare and run my home made one.

Beater said:

Well, you know, look at the truck I was putting it in.


Perfect timing that you bumped this thread. As noted above, drive shaft I had in the truck was too short (it was built for a friend's truck, but since both our trucks are hacked up our wheelbases are slightly different). So there wasn't enough spline engagement on the shaft I was running and I had a ton of wobble/vibration coming from it.

I swapped in this cobbled-together hack job last Saturday and the truck rolls down the road WAAAAAYYYYYY smoother than before. I'll keep the short one as a spare and run my home made one.

Click to expand...

i know i'm gonna have to build a front shaft for my s-10 blazer, i'm in the middle of doing a solid axle/leaf spring swap, and ( inadvertently) lengthened my wheelbase by a couple inches.
plus the trans xmember is in the way now, along with the exhaust on that side
and so on
and so on
and scooby dooby dooby