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post #1 of 6 Old 09-19-2002, 04:22 PM Thread Starter
rustyCJ
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cracked pumpkin

I have a crack in my axle pumpkin where the axle tube enters it on my front 30. the crack is on the top and I can tell that the weight of the jeep will slowly spread it open. the crack is on the short tube side and the spring U-bolt wraps over it. heres the question, can i weld the pumpkin/axle tube or when I'm driving down the road will the axle snap in two? Anyone done this to an axle before?

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post #2 of 6 Old 09-19-2002, 09:56 PM
dana60cj
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No, I have not done this before first off.

Welds make the original metal stronger so they say. They must be the welders union.

If it is near that u-bolt who knows how far it goes into the pumpkin? A weld should hold for a while. If you do weld it make sure the areas that are cracked are flush. Just jack up the jeep by the pumpkin and the weight from the rest of the other end of the axle will make them flush.

Geeeeeesh did You do this? Time for a Dana 44 or a 60?
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post #3 of 6 Old 09-19-2002, 10:05 PM
only in a jeep cj
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I'm sure someone will disagree with this, but if it were me, I would replace the housing as the Dana 30 is a common unit. I'm surprised it cracked on the short side as they are more common to crack on the long side. Yes, you could weld it, but what else is bent/damaged that caused the crack or is a result of the crack? If you have high miles on yours and find a good used one, swap it straight up if your gears match, OR rebuid it and have a solid axle when done.

Ed
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post #4 of 6 Old 09-19-2002, 10:22 PM
CSP
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Welds don't necessarily make the original metal stronger. Usually the weld itself is stronger than the metal around it.

No matter what the case is there's no way I would try this. The problem is the pumpkin is cast iron. It is not steel and becomes very brittle when you weld it. Brittle means it will crack even worse than before the "repair". It's possible to weld cast, but there is a very precise procedure (preheating and slow cooling) that must be taken and the proper kind of rod must be used. Also, since the axle tube has already made the crack wider you no doubt already have a tube that's out of alignment. The tubes are a press fit into the center section and you'll never get the tight tolerances needed for seal life, gear wear, wheel alignment, etc..

Dana 30's are a dime a dozen if you look in the right places. You should be able to find one fairly cheaply from someone upgrading their old axles. An upgrade to a Dana 44 is an even better idea.

Last edited by CSP; 09-20-2002 at 11:21 AM.
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post #5 of 6 Old 09-20-2002, 09:36 AM
4wheeler4CJ
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Thumbs up

If you have a Narrow Trac, I have 4 Dana 30 Front Axle Units for sale for $150/ea. Some have disc brake setups, some have the 11" drum setup.

Should you decide to replace it, you can email me at ericnmish@yahoo.com. All have 3.54 gears.

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post #6 of 6 Old 09-21-2002, 07:34 AM
werewolf7111
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its best you DON'T attempt repair

CSP gave you some sound advice. I dont generally respond to posts but I have decades of designing machines and "upgrading" jeeps and I am going to tell you the caveats of what you may be thinking and as an engineer, why its not best you attempt it.

pumpkin- this is an investment casting( a coarse grain) which is NOT designed for axial load in an X and Y plane( up/down, back/forth)- due to the extremely low carbon content and high molecular clearance of a casting by design, if you apply heat, you will definitely alter the grain structure and cause further down range problems

shaft tube- this is cold rolled drawn tubing- the problem here is 2 different metals and a different coeffecient of thermal expansion- plus you "see" this crack but you DONT see the runners( only ultrasonic testing can find these) so you will just end up "moving" the "crack" ( in engineer speak- a "crack" is molecular in nature and has yet to break the surface- when it has, its referred to as a fissure)

alignment- assuming you wanted to proceed- you would need to have the unit cryogenically stress relieved- then jigged and lasered to find true alignment-then uniformly heated- then welded- then cryoed again- it aint worth it
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