Ford 9" housing crack

[knightfire83]

(Ford 9" on a 1975 F-100 4x4)

During my conversion to 4wd I replaced the pinion seal in the rear end and refilled the gear oil.

The next day I saw a mid sized puddle of oil under the rear end. Closer examination of the leak revealed that there is a long tiny crack on the rear end housing causing this.

The crack is located on the weld on the opposite side of the carrier assembly. (facing the rear bumper) It is pretty close to a hairline crack on the inside of the weld.

So I have two questions:

Can I take the truck when it is finished to a welding shop to just quickly have this welded up, or do I need to get a new rear end housing?

If the crack can be welded up, will I have to remove and disassemble the housing to have it welded? I would think the gear oil inside would contaminate a good weld, or at least be a fire hazard.

This seems to be the only big problem I have ran in to so far during this conversion, I'd be very interested on the best / easiest way to fix this problem.

I'll attach a pic I found on the web for reference. The arrows are pointing to the outside of the weld, but the crack is on the inside.

Thank You

[Wes]

I would think it could be welded. Yes the gear oil will need to be removed, and the repair area clean very well.

[convincor]

I would be concerned with why it's cracked. You know the history of the housing? Where'd it come from? Is the crack a result of a accident? Housing may be bent?
There's tons of housings out there and think you could get another for next to nothing. I'd swap it out.

[convincor]

exampes- http://cgi.ebay.com/ebaymotors/Ford-9-i ... enameZWDVW
http://cgi.ebay.com/ebaymotors/FORD-9-I ... enameZWDVW

[AlleyCat]

I'd get your welder to vee the crack and weld it up.Drain the lube so it doesn't cause a problem and wash the are with spray brake cleaner just before welding.

[knightfire83]

Thank you all for the replies, I really don't know the history on the donor truck. It never crossed my mind for some reason, that it may have been in an accident. I think I may just look for another housing to be safe.

[FORDification]

If you want to take an hour drive up northward, I've got a bare housing that I'll give you for free. PM me if you're interested.

[knightfire83]

That is a very generous offer Keith, would the spring perches be in the correct place for a '75?

I'll see if I can arrange transportation. Thank You very much.

[FORDification]

WHOOPS! Sorry, I didn't catch the part about it being for a '75. No, this is a bumpside-era housing.

[knightfire83]

Thats cool, thanks for the offer.

[knightfire83]

Thank you all for the information. I have a lead on a bare 9" housing off a '79 ford 1/2 ton 4x4 for $25.

I imagine all the parts off my cracked '75 differential will bolt into this housing and match up to the springs..... Is this correct?

Would there be any problems do ya' think?

[fordman]

i think you are going to be alright with the 79 housing.

[AlleyCat]

Thank you all for the information. I have a lead on a bare 9" housing off a '79 ford 1/2 ton 4x4 for $25.

I imagine all the parts off my cracked '75 differential will bolt into this housing and match up to the springs..... Is this correct?

Would there be any problems do ya' think?

It all bolts right together.

[68swb]

and the price seems right, good luck on the swap should no be difficult. let us know how it goes.

[knightfire83]

You bet, I picked it up tonight. Looks to be the same housing.

It may be a while before I get to the rear end fix. Gotta put the engine in, electrical, and align the box to the frame yet.

Thanks to all !!!!