chet

Well, I am attempting to replace my a/c expansion valve, and I have the firewall out and was struggling with the two hex socket head screws that attach the expansion valve. I got one off, but it now appears that I have stripped the other. Anybody have any suggestions on how to remove it now that I've stripped the hex socket?

jimq

I did the same on the fan belt hex heads. Dremel a slot for a regular screw driver bit if you can get one in there. I ended up hitting the slot at an angle to break the bolt loose.

BobbyT

I stripped one while removing my seats. I gave it a shot of Wurth Rost-Off, then a couple of stout taps with a chisel/hammer at the angle to loosen it, and it came right out.

MN993

Try this. Works great if you have the space.
http://www.irwin.com/irwin/consumer/...rwinProd100512

chet

On the expansion valve, those screws are seated down in a recess. I think I may have to drill it out, but I've never done anything like that before. The expansion valve is going to be replaced, so I don't have to worry about that, and I'll be wanting to replace the screw (hope the dealer has it on hand). I'm just not sure whether any of the drill bits I have will drill into the metal screw. The only thing I've ever tried to drill through is wood.

oliverjamesthomas

My advice would be to use a KLANN stud extractor. It's the best piece of equipment I've ever seen over here in England for doing this type of job. You boys over the pond might have something similar or better though....!

The beauty is that it really gets hold of a bolt or stud and actually tightens as you turn.

Here's a link:

http://www.toolweb.com/irep-supplies...rtno=kla0181-3

Regards

Oliver

Garth S

As it is in a recess, select a drill just slightly larger than the allan key and behead it - the threaded shaft left behind will likely spin out with finger pressure. A drop of heavy oil on the drill tip will help drilling and containing the chips.
If in doubt, practice on a couple of old bolts or metal plate ( this leads to the discovery of why flat metal surfaces are center punched prior to drill contact ).

Ron

You are correct. It's very easy. I've had this problem before on some of the older Mercedes vehicles I work on.

All you have to do it drill the hex head off and the expansion valve will slide right off. The part of the hex head screw that remains will then most probably screw right out, by hand, of the little metal plate that it goes into with out any problem.

To drill the hex head off I use a right angle drill, also called a close quarter drill.

OCBen

It's a great product. Thanks for the suggestion.

Worked like a charm today.

Black993

Yep. Just get the head off and it will reduce the pressure on the threaded part of the bolt and you can undo it by hand.

Had to cut the head off one of my valve cover gasket bolts.