One of the control arm brackets has rusted and broken off the rear axle housing of my car. I can make up a new bracket, but then need to weld it to the axle housing.. The axle runs inside of this in oil-from the differential. Can I weld to it without starting a fire? Any advice
thanks, Scott
Drain the oil.
Pull the diff cover. pull the axle, wipe out the tube with rags, weld, reassemble, relube.
Carl
You could probably do it without pulling the axle but my recommendation would be to pull the axle first. Depending on what kind of car it's usually not that difficult. that way you can drain the oil (change it while your at it) and you will be able to see into the axle housing to make sure nothing has happened.
Jim
I recommended pulling the axle as a way to allow wiping out the tube. The gear oil is thick enough that a coating will remain in the tube and there is still a chance of fire even if you drian the differential. Pulling the axle is not that hard.
Carl
On Wed, 27 Aug 2008 18:33:28 -0400, with neither quill nor qualm, "Carl Boyd" quickly quoth:
Or maybe just clean & unscrew the vent then charge the housing with argon before welding. No fire could happen despite the presence of the oil.
-- Smokey the Bear's rules for fire safety should apply to government: Keep it small, keep it in a confined area, and keep an eye on it. --John Stossel in _Myths, Lies, and Downright Stupidity_
I agree Carl. One would hope that the welding won't build up that kind of heat. Another consideration is VENTILATION. Even if it doesn't catch fire, the Diff oil will SMOKE and you don't want to be breathing that stuff. Make sure you are outdoors or have a very good fan pulling fresh air in and exhausting the smokey crap. When I was racing mini-stocks we welded the bearing to the flange so that if an axle should break it wouldn't become a vaulting pole. I never had any trouble with fire but there's always the chance.
Jim
I can't recommend it because of the potential hazard, but I had a Dana
70 dually rear from a rescue wagon that I installed in a 3/4 ton pickup a different distance between the springs. I ground off the old welds holding the original spring perches to the axle tubes, and MIG welded new perches on, without opening the rear or pulling the axles. I just let the axle tubes cool a bit between passes with the MIG. I guess there was not enough air in the housing to sustain much of a fire, or the oil never lit off. Each of the four weld beads was about 3-4 inches long. In any case I've put 200K miles on the rear since without issue.What's that Lassie? You say that SCOTT fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Tue, 26 Aug 2008 22:50:42 -0400:
Jack up one side of the axle so the oil runs to the other side.
Or maybe jack the other side so the oli cools the weld area. If there is only residual oil it may smoke & catch fire? Is there enuff O2 inside a smoke filled diff housing to sustain a fire anyway??
Straighten the housing after welding.
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