flexin91xj

Im rebuilding a rear dana 44 and the the brake junction box(T junction) was origanally mounted to the dif case but it needs to be near the drivers side brake backig plate as that is where it is on the dana 35 on my 91 cherokee. The junction box has a hole in it where a longer dif cover bolt was mounted though it to keep it secure on the dif. I wanna weld an upside down bolt on my axle tube so I can mount it closer to the drivers side.
My question is, can I weld any type of bolt to the axle or do I have to use grade 8 hardware?

5-90

Any carbon steel (SAE- or ISO-graded) screw can be welded, once you've chewed the zinc plating off (SAE5 are straight zinc, SAE8 are zinc chromate. ISO screws are all straight zinc.)

flexin91xj

Sweet! Thanks. So I could use one of the stock dif cover bolts and it would weld up just fine? As long as I clean it up and prep it up really well.(as in anything you would weld)

5-90

Yawp. Only difference there is you'd be removing a black oxide coat, instead of zinc electroplate. Different method, same result (nasty weld if you don't remove it.)

The zinc will boil off and you'll have blowholes in your weld - and breathing zinc fumes isn't so good for you. The black oxide will just kill your penetration.

Apart from that, once you've clean up the metal you're working on, go ahead and melt it! Just make sure you clean the end and at least some of the sides of the head off so you can get good penetration, that's all...

Ed. - If you were brazing or soldering, the zinc wouldn't get in your way at all, although I'd still burn the black oxide off. I've brazed/soldered galvanised hardware together before. If you can get yourself a good clean surface on the axle (no paint,) brazing might be easier. You don't need that much strength. Drilling and tapping a hole in the tube is also a possibility, then just run the screw down through the T-block instead of dropping it on and running a nut down on top of it. If the tube is at least 1/4" thick, that should not be a problem...