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Tips
Tips

Removing broken stud from Aluminum

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M

mk2sprite

Jedi Hopeful
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I guess this is basically a metalurgy question. I broke one of the small bolts that hold the OD Solonoid to the aluminum transmission body. Can I heat this to try to remove it? There is a tiny bit of the stud still protruding. Can't remember if heating alum to remove a steel bolt is a no no?
Thanks
Mike
 
Light heat with a propane torch is OK.

Obviously, watch for an oil fire.
You could also try some PB Blaster spray to loosen it
(but don't apply while you have an open flame nearby!)

My preference for removing these (and I've removed many broken studs), is to use a left-handed drill bit.
Center punch the broken stud with a good center mark and drill into it with the LH drill. Since the electric hand drill will need to be turning backwards, it will tend to try to twist the broken piece out. Often, when you're about 1/2 way down into the stud, all the twisting and vibration will cause the stud to unscrew.

And for the record, I dislike Eze-Outs. They tend to "wedge" the stud tighter and then break off, leaving a hard, un-drillable piece of steel in place.
 
Good piece of adivise buy the previous post. I prefer to use an over size nut and weld it to the broken stud. The heat from welding will make an easy job of it. I only utilise drilling as a last resort, as the alli case is softer than the metal stub if you miss.
Cheers,
David.
 
If The stub left sticking out is sufficient to get a grip on it with vice grips, then the first try should be with heat, but with a something extra. Heat the stud and surrounding aluminum as hot as you can get it, then touch some paraffin wax (candle wax) to the joint and let everything cool a bit. As it cools, the wax will be drawn down along the threads and will usually make it so you can back the stud right out. I am with David, unless the stud is 1/4" or larger, using a drill can become a disaster real fast unless you are real good with a hand held drill.
Cheers,
 
I'm with you guys on the drilling which I only want to use as a last resort. I do only use left hand bits for this type job but the stub that is left is very small. I can't even get a good grip with vise grips but I have a set of dykes that will grip it but it won't turn. The wax sounds like a good idea and I will give it a go
 
Try a 50/50 'slurry' of ATF and acetone as a penetrant. Heating it will expand the aluminum more than the steel, actually compressing around the broken stud more tightly, BTW.

Time and penetrating solution may be the better way.
 
Well after furthur review it looks like my only option is to drill it out.
It is such a small stud and there is just not enough left protruding to get a grip on it. I may wait for help from someone with decent eyesight before attempting this one... never easy
Thanks
Mike
 
If the transmission is out of the car it may be worth the bucks to take it to a machine shop, they'll be able to set it up and mill out the old stud without risking damage to the OD case. I'm always cautious about using heat around aluminum, if you get it too hot it gets brittle depending on the alloy so be careful there. I did that trying to anneal some aluminum tubing for an intake manifold I was bulding, had one piece just crumble when I tried to form it later.
 
Good advice from Bill. I am always very leery of trying to drill small studs out of aluminum as my usual luck is to wind up with a hole that drifts off the stud and makes a large hole in the aluminum, next to the stud. If this happens it doesn't take much to wind up with a hole that is too large to install a helicoil in and the whole project snowballing into a real expensive venture.
Cheers,
 
Often I will use a grinder to flatten off the top of the broken bolt so that I can get the drill bit (usually preceded by a center punch) in the center of the stud. Before it is ground smooth it is hard to find the center of the rough top.
BillM
 
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