I'm not talking about my crack! I need to weld shock mounting brackets on my rear end. My question: if I weld it as is, is there a danger of heating the grease, etc. inside to the point of a fire or explosion? Is it even an issue? Naturally, i'll remove the gas tank before I start this, but I want to make sure I'm not igniting a grenade. Here's a couple of pics:
if your not doing a whole lot of welding you can leave the grease in it. there is a chance that it could coke up on the inside but if your careful not ot overheat the area you should be ok. there is always a chance of fire though, especially if the grease is old and god-knows-what has settled in it.. but witha simple shock mount you should be ok. here is a post i did on welding on a rear.. Hope it helps although it may be overkill for just a shock mount: http://www.jalopyjournal.com/forum/showthread.php?t=105268
Thanks! The wet rags are a good idea. I'm like you, I think if I take it slow, and in small stages, it should go fine. Maybe tack one side while the other cools, etc.
exactly... it really works well... i've done two rears this way with no distortion.. alot of people will tell you that you don't need so many precautions but i have seen housings warp. that's why i'm so careful.
id be terrified id ruin my bearings and gears. as the current flows through the axle it will go through any conductor. seeing how bearings and gears are made of steel, id be afraid of molecular adhesion welding those tiny contact surfaces. sure it may brake loose as soon as you rotate them, but by then the damage will be done, causing premature bearing wear from spalling or brinneling. seems to me the safe bet would be to tack up what you need and remove all internals to finish weld.
The safest way, in my opinion, to keep the bearings and whatnot free, is to weld it while it's moving. I'll drive
the beauty of electricity, it takes the path of least resistance. that will mean if you put your ground clamp on the housing near where you are welding, the current has a short easy path to follow, no significant current will be travelling through the bearings etc. it'd be a different story if some moron put the ground clamp on an axle shaft and welded on the housing.
Good info. I'd like to add that you should confirm that the axle housing vent is clear to allow for air expansion due to heat.
I have modified many rearends by adding spring pads, panhard mounts, shock mounts, etcetera, and never had a problem. I do not drain the oil from the rearend, although you may find that if you don't, and you are rotating the rearend on a stand to give access to all the "weld" areas that the grease will run out the vent hole and make a great big mess. I always design my brackets so that they are full 360 degree brackets, then split them to fit them over the axles tubes (that way you don't have to disassemble the axle tube ends to slide them over.) The fact that weld is applied all the way around the bracket keeps from building up stresses on one side of the housing only, which could conceivably warp the housing. I have never removed the axles, bearings, or gears while modifying a rearend, and yes, definately hook the ground clamp to the rearend housing itself, not the axle ends, nor anything else that would flow electricity through the bearings.
The Jalopy Journal
