89 Ford 4x4 rear end

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  #1  
Old 09-10-08, 05:53 PM
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89 Ford 4x4 rear end

I need help for a friend who's not Internet savvy.
I will do my best to describe the problem, and I have to admit I never saw this happen before.

The Third member or chunk ...I've heard some call it... came loose from the tube (axle cover) only way I know to describe it...allowing the third member to tilt upward to the point it crack the u-joints. This happen while he was pulling a heavy load up a hill.

Now. It appears that Ford used a plug weld to fasten the third member to the tube. The plugs on the driver side came out, but the plugs on the passenger side still remain in the plug hole but are no longer fastened to the axle tube. My friend has a new Dodge and they did not use the same method (plug weld) my term... they use what looks to be some type of pin to keep the chunk from spinning on the tube.

How would be the best way to fix this? My friend wants to weld the outer flange on the chunk to the tube. That might work but not know how thick the tube is, I have second thoughts about doing that.

Your Ideas would be greatly appreciated
Billy
 
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Old 09-10-08, 07:20 PM
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The remnants of the old weld should be taken out and the tube aligned to its original position and rewelded through the plug hole you have mentioned.

Do not do a circumference weld around the tube to the differential casing( what you're calling the chunk). That type of weld can over heat the material in the tube and weaken it to the point of breaking under load.
 
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Old 09-10-08, 07:37 PM
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you can do a circumferential weld but you have to weld a short piece at a time to avoid overheating. that was a factory repair for dodge differential leaks in 1977,

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Old 09-11-08, 05:32 AM
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Originally Posted by marbobj View Post
The remnants of the old weld should be taken out and the tube aligned to its original position and rewelded through the plug hole you have mentioned.

Do not do a circumference weld around the tube to the differential casing( what you're calling the chunk). That type of weld can over heat the material in the tube and weaken it to the point of breaking under load.
Marbob, Thanks for your reply. The term chunk in the south by some old shade tree machanics meant the rear end.

Any ideas on how to properly align the defferential? At the moment the front is tilted upward a bit.
 
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Old 09-11-08, 06:19 AM
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Originally Posted by Speedwrench View Post
you can do a circumferential weld but you have to weld a short piece at a time to avoid overheating. that was a factory repair for dodge differential leaks in 1977,

life begins when the kids leave home and the dog dies

Thanks Speedwrench for your input.

I was thinking of doing 1/2" welds, maybe three of them on each side.
 
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Old 09-11-08, 06:22 AM
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The circumference weld to avoid weakening the tube is a more technical type of welding with controlled heat application as well as material used. There are a number of variables that would have to be considered and isn't for someone not well versed in that type of repair. One of those variables is amount of metal mass in the differential casing verses the metal mass in the tubing with a common weld.

I would advise not using that method.

As far as alignment, there should be some signs of the previous alignment on the axle where the tube mates to the differential. I would take the easy way out and return the parts to those. If there isn't anything evident you could remove the axle and lay straight edges on the spring saddles.The straight edges would have to fall into the same plane on either end of the axle.

The complication is positioning the center line of the pinion casing relative to that line. Because of the drive shaft line coming to the differential that differential may have a slight incline to give better u joint performance. For lack of a better way to do this from scratch, I would level the pinion parallel to the spring saddles and weld it in.
 
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Old 09-11-08, 10:17 AM
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Originally Posted by marbobj View Post
The circumference weld to avoid weakening the tube is a more technical type of welding with controlled heat application as well as material used. There are a number of variables that would have to be considered and isn't for someone not well versed in that type of repair. One of those variables is amount of metal mass in the differential casing verses the metal mass in the tubing with a common weld.

I would advise not using that method.

As far as alignment, there should be some signs of the previous alignment on the axle where the tube mates to the differential. I would take the easy way out and return the parts to those. If there isn't anything evident you could remove the axle and lay straight edges on the spring saddles.The straight edges would have to fall into the same plane on either end of the axle.

The complication is positioning the center line of the pinion casing relative to that line. Because of the drive shaft line coming to the differential that differential may have a slight incline to give better u joint performance. For lack of a better way to do this from scratch, I would level the pinion parallel to the spring saddles and weld it in.

Thanks Marbob, I think I have a handle on it. I really appreciate it,
 
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