Stripped Bolt

[SkyPirate]

I've had to weld a bolt with a hex head to some allen head bolts to get them out,.which puts heat to the bolt in the aluminum at the same time but gives you a more solid bolt head to turn,..like Slyfox said as well ..smacking the head of the bolt that's stuck sometimes jars things enough to losen the bolt too,.. just use a punch tool to avoid smacking the casing ..cast aluminum can snap pretty easily if a other then designed load is applied..
I'd re install a couple bolts to hold the housing from moving until I got the bad bolt out.

Chase

[Slyfox]

some more tricks I've used, after heating up the bolt, very important, I have used a chizel and angle it and hit it in the direction to loosen, Also if you can get a small pair of locking plyers on the head, that works also. Sometimes you can grab either the allen head either in metric or standard in a slightly bigger size and hammer it into the hole. You can also take a torx head and try putting it in there. I work on transmission and there are times that I run into the same thing and the only way to remove the bolt is to heat it up and than remove.

When you first try to remove the bolt if it's in there tough, that's the time to head up the bolt before stripping it out. I love my oxy tanks for that stuff. Oh and don't use the cutting torch, use the smallest tip you have, the one I like has a 0 on it. The 5 is a little to big and adjust for the smallest flame.

[Paul Z]

I would recommend heating the bolt up, then tighten it to break the loctite bond, and to prevent stripping the hex in the loosening direction, then loosen the screw. Be cautious not to overtighten especially in aluminum.

[Slyfox]

I found that a 6mm hex head socket is the right one, the 1/4 size is a little bit bigger, you might be able to hammer the 1/4 hex socket in there to get it out. If not find an easy out. But heat it first.

[Av8r3400]

A T-40 torx bit is .260" from point to point.

A 1/4" (.250" flat to flat, .289" from point to point)

A 6mm (.236" flat to flat, .272" from point to point).

This makes a t-40 an excellent tool to tap into a stripped 6mm socket head cap screw. The torx bit will hold much more torque than a hex shaped socket.

Give it a try and see.

Some heat is good to release locktite, but heating the aluminum is dangerous. It may damage the case if too much heat is applied. Never use a torch on this application. Heating the screw itself will only make it expand and get tighter.

Heat the whole area with a heat gun.

[Slyfox]

sorry i disagree totally on this. I been doing transmissions for 30 years and have been using my techniques for as many. You must be going on theory on what you say. If you are careful and use a very small tip you can heat up the head of the bolt and it will come out. I can prove it through having to do it. Sorry guy.

Now this is my theory, you heat up the head with a torch, you concentrate the heat right at the head. Sure the bolt will expand, but, what I think is important here is the head releases itself from being a clamping force on the parts. So now you have just the bolt to turn out. I don't remember the bolts having locktite on them when I did my gearcase on the 912ul, but that might have changed. With my procedure that to will be taken care of because it doesn't take much heat to release the locktite. So tell me, did the bolts you did take out have locktite? It should be a white look and caked up on the threads, not only that the bolt will come out tight all the way out.

If you are skepticle just put small amounts of heat at a time to the bolt and try unscrewing it, if it doesn't work, add a little more heat. Years ago I thought like you and fought with removing bolts that stripped the heads, than I grabbed the torch and started getting them out.

steve

[Av8r3400]

Do as you like. Personally I wouldn't get anywhere near my $20k motor's gear case with a torch, but that's just me.

In 30 years of tranny work, I'm very surprised you haven't used the torx bit trick. That's not theory; it works very well. (Almost 20 years of being a machinist.)