BENT MAIN DRIVE SHAFT; OK TO RUN IN FRONT WHEEL DRIVE ONLY?

[Eagleearl]

The parking brake "popped" this morning and the car went over a rock ledge, picked up a couple hundred pound rock on the way and carried it another hundred feet till the rock caught on another rock.  The drive shaft damage/bend is about 1/3 back from front u-joint.
[/quote]from HANNAJACK

FROM EARLIER POST

[txjeeptx]

Wow, Eagle took itself on a joy ride. Good luck with straightening the driveshaft enough to drive into town. Amazing the driveshaft was all that got bent.

[hanajack]

All good stuff. 

I removed the drive shaft. 

My concern about the backyard straightening is that there are two rather deep 5" to 8" long gouges/dents in the shaft as well as the bend. 

My other concern is that reading MR 251, there is great emphasis on balancing.  Hard to imagine that a machine shop, let alone a welder, could come up with a means of balancing a re-tubed shaft. 

There used to be an Eagle Limited in the wrecking yard on the other side.  Would any 4x4 Eagle have the same shaft?

[mudkicker715]

A 4dr sedan would be the same as a wagon.

[hanajack]

Any year?

[mudkicker715]

Any year

[HappyPappy]

Man, don't heat that drive shaft to much. I had one explode that was left in a car, set on fire, went out through the roof and raped around an oak tree. Had to use a torch to get it off the tree.

 If you cut the drive shaft with a pipe cuter that will give you two nice beveled ends to work with. Cut out the bad section and put in a new piece of pipe, tree limb, sticks and stones or what ever.  LOL  Drive shafts are made out of tubing, find the right size will be the hardest part. Do you have any bone yards near you? May find something there.  Good luck

[carnuck]

Balance is for higher speeds (above 30 mph). Alignment of the Ujoints (they have to be mirror imaged at each end so the yokes have to be correctly mounted) is far more important. I used to do driveshafts with a pipe lathe (it had a 6" through head) and a stick welder. Most were so good they didn't even need balancing when checked. When you weld the yokes on, you need to be sure the old weld is removed enough from the yoke that the alignment step will fit inside the new tube tightly. I do a slight bevel inside the new tube to help the yoke slip in with just the tap of a hammer.
   Start a spot weld on one side of the yoke and spin it in the lathe to ensure it's not wobbling then start to weld on the far side from the spot right up to the spot and around to where you started in one pass if you can or leave a puddle on either side to keep it balanced.

[hanajack]

Carnuck,  That is some really good detailed advise.

I  marked the alignment and removed the drive shaft at the "spiders"; it is all still intact.  Actually, the drive shaft front spline/slip fit didn't want to come all the way out of the front yoke.   So, with the yoke on the axle end of the shaft and the spline on the front end, do you suggest that spline and front yoke remain intact when doing the cutting and welding?

Do you know what the ID of a new tube should be?
Also, the the minimum wall thickness acceptable?

[carnuck]

Sorry, I don't know what the current driveshaft diameter is. I do leave the ends on when i cut them as it makes it much easier to realign and check for wobble when done. Some of the first ones I did with a cut off saw and they turned out horribly wobbly. Tape the ujoint caps or use a piece of motorcycle (or small diameter car) inner tube to keep them from falling apart.

[txjeeptx]

If you do decide to take the splined slip(collapsable part) of the driveshaft apart, then you need to mark it for realignment. The crosses of the universal joints must remain in phase with each other, in ither words, the crosses line up with each other at each end. The "spiders" you are referring to are probably the universal joint crosses. The parts that stay on the transfer case and axle are called yokes.

The driveshaft tubing needs to be actual tubing, NOT water pipe or fence pipe or exhaust pipe. If you can find a junk driveshaft form some other vehicle that has similar size tubing and is longer than the section of the shaft that needs replaced, then that tubing will do the job for replacing yours. You'll need to find someone who can weld, and has a decent knowledge of how to measure and can cut square. I'd recommend using a chop saw, rather than anything else(grinder or torch), to get the cuts square. I have used a piece of angle steel to lay the pieces of driveshaft in to hold them square to each other before welding them together(remember to make sure the u-joints are in phase!). This was for a low-speed off-road only driveshaft that didn't need balancing. Only a machine shop has the tools necessary to balance a driveshaft for high speed use.

The best thing to do is to have the tubing replaced by a professional with the specialty tools that allow them to get the ends on straight, in phase, they'll have the correct kind of tubing to do the job, and they'll balance it for use on the highway. Generally, a new driveshaft costs me around $200 here in TX. You will probably have to take it to a machine shop in Kahului. Google "drive shaft repair" or "machine shop". Seki's, maybe? Call em.

[hanajack]

Thanks for the correction on my use of the term yokes.  Think I got the "spider"[u-joint] term from the manual.

Yes, Seki's would be the place, but don't know if Roy Seki is still active.

If necessary, what would be the source of a new drive shaft of which you speak?

[txjeeptx]

The machine shop would build a new(or a re-tubed) driveshaft either using parts from your old one(re-tubing), with the bent tubing cut out, or they could order(or might stock) the parts("stub and slip" collapsible part, and the u-joint yokes for the driveshaft-side of the joints),  from Spicer (the manufacturer). They should have a fixture to hold the parts together for welding, and lathe that allows them to spin the driveshaft at high speed to watch it for wobble, and a strobe light to help them locate where to put a balance weight. I've had driveshafts for my Jeeps retubed for a little as $150 when all the parts of the driveshaft were good and useable, but the old stub and slip can wear out to the point where the machine shop can't balance a re-tubed shaft. Then they either require me to buy new parts or they won't warranty the shaft and won't balance it, or they might refuse to use the old parts. I usually bring the driveshafts in to a machine shop cleaned of all grease, sanded off most rust and paint, and removed u-joints, so they don't have to do a bunch of cleanup work first.

The machine shop may need you to measure the distance between the rear transfer case output yoke and the differential pinion yoke, if the old driveshaft is too severly bent to measure from, and if the car is lifted/ otherwise modified from stock. That is the reason I usually have driveshafts redone - lifting changes the length needed for the driveshaft.

My wife wishes I could arrange to deliver you a replacement driveshaft and take her with me. I told her where you live. Wishful thinking.

[hanajack]

     Just found out that the Eagle in the wrecking yard was crushed.  My ace in the hole was a joker.  Regarding my stub and slip, it was/is packed with grease and has 81k miles on it - should think it's OK.

     Meanwhile, there are tons of Jeeps on the island.  Would there be any will-fit, cross over Jeep shafts?  I would prefer to try to get another shaft rather than re-tube mine.

[carnuck]

Measuring is the only way to go. If there are any FSJs (Grand Wagoneer, Jtruck) the front shaft may be the correct size (I vaguely recall having one side by side with an Eagle shaft) Just recall that none of the slip yoke shafts will work, so XJs are not on the donor list.