sailor56

I have been trying to remove the fill plug on my 1987 911 with G50 transmission for about 3 weeks. The bottom plug came off with a breaker bar and I drained the oil before I tried to remove the fill plug. Whoever put the plug on last stripped out the 10mm hex head. I have used some heat on it (not too much as the fuel line is directly above), with only being able to use vice grips in a very limited position. As a last resort, I had a 15/16" nut welded to the top of the plug. The nut simply broke off of the weld. This is supose to be a fill plug that is easy to remove, not some rusted on exhaust bolt. At this point, all I can think of is removing the engine and transmission just to get this plug out. Does anyone have any experience with this problem? Thanks for any help.

JBO

Obviously you've learned the lesson of always loosening the fill plug first, so if you can't get it you can drive the car somewhere to have it done. I would probably bail at this point and have it towed to a shop. I've BTDT before on projects, and you don't want to do something that compounds the problem.

TMH

Also been there, but I had done a search before I tackled this job and had attempted to remove the fill plug first.

Eventually I was able to get the fill plug out, when I had already gotten a replacement. It was not pretty, but there is not a lot you can do within the space constraints. The fill plug has a pretty beefy flange which extends to the outer edge of the plug (larger than the hex portion of the plug). I used a standard chisel and hammer to "break" the plug free. Yes, it made a significant gouge in the flange of the plug, but I was going to replace it anyway. Once it "broke" loose, it was easy to virtually loosten and remove by hand. It was just an issue with overcoming the fact that it had "welded" itself into place after having not been removed for so long.

If you do a search you will find that others have gone so far as to have a piece welded onto the plug in order to remove it. Hopefully you won't have to go that far if my method works for you.

Good luck,
Tom

sailor56

Thanks for the quick reply you guys. I have learned my lession about taking out the fill plug first!! It is the "easy" jobs like this that catch you by suprise.

Tom, could you be more specific how you used the chisel and hammer to "break" the plug free? Did you just bang on the top of the flanged plug to loosen up any corrosion or did you use the chisel to actually break the plug apart. I have already tried to weld on a bolt as explained in my original post to no avail. I thought I might try heat, direct shock ato the top of the plug with a hammer and chisel, and have another nut welded onto the top of the plug. Thanks for your help.

Last resort is to have the car towed to a shop, however, I'm not sure they have any other approaches that I have not already tried to take care of this.

TMH

I did not use the chisel to break the plug apart. Since you have the most room from below, I placed the blade of the chisel at approximately the 3 o'clock position on the edge of the plug flange, and contacting the flange edge at about a 30 degree angle (the edge of the chisel is perpendicular to the edge of the flange). With this positioning, when you hammered on the chisel it would gouge into the edge of the plug flange, vibrate everything to loosten corrosion, and try to push the flange in a ccw (loostening) direction. As I say, after maybe only 5 minutes of this, it broke loose, and was able to be loosened the rest of the way by hand. I guess that the threads are not like "npt" threads because the seal is accomplished by the brass crush washer. Therefore, once the corrosion grip is broken, the plug came out easily.

Tom

P.S.: My problem was also on an '87 G50 transmission.

lostinatl

Leverage. I jack the car up and use an old fence post, three or four feet long, hook it to the breaker bar and hold it in place while I have one of my kids gently lift in the correct direction. Always works. Makes a nice pop when it comes out. I am the one who puts the plug back in and yet I always have to use this method to get it back out? The first time I tried to do this I could not, took it to a mech, who did just what I now do. Although he did not use a fence post, he used a pipe. I thought mine was cross threaded also. It was not. They seem to get tighter on their own.

scottb

It's interesting that the welded nut broke off. Would it make sense to have it re-welded (better this time) and then try again while applying heat? I've heard some people say you should try tightening it a bit before backing it out. I guess the theory is that once the corrosion is broken you can then loosen it. Rather than dropping the engine, can you do a partial engine drop and then apply heat without the danger of the fuel line?

Do a search here and on the 911 board at www.pelicanparts.com. While a pain in the butt, frozen transmission plugs are not uncommon. I'm sure you'll find a wealth of information.

Good luck. Let us know what happens.

redidrum

Man, was I warned about that hapening 10 times! Perhaps dry ice on the plug since it would shrink it slightly. Then try to remove it. I don't know how much access you have. Good Luck.