Every time I loosen a drain plug from a Mercedes transmission oil pan or torque converter, I have a sickening fear of camming-out the 5mm female hex. I haven't had it happen yet, but did have a case where the hex bit turned about 20 or 25 degrees before the plug loosened. The other day, a local indie had a drain plug cam-out completely. He had to weld a nut to the plug to remove it. Fortunately, it was the oil pan plug, so he could do the welding off the car. The Mercedes transmission drain plug is a DIN 908 with M10 x 1mm thread.
Maryland Metrics carries a DIN 910 plug. It is same dimensions as the DIN 908 plug, except that it has a hex head which is 6mm high and 10mm across wrenching flats. I am thinking seriously at installing DIN 910 plugs when I service the transmission fluid and filter in my 123 body. I plan to put a lump of modeling clay on the torque converter plug and turn the engine one revolution to be sure there is clearance for the extra 6mm plug height. I am also considering using the DIN 910 plugs when servicing customer transmissions.
What are the pros and cons of using the DIN 910 plug instead of the DIN 908 plug? Have any of our forum members made this substitution? Comments? Precautions to observe? What is a good method for removing cammed-out drain plugs that doesn't involve welding?
The DIN 910 plugs are $ 1.51 each. Maryland Metrics also has 10mm ID by 14mm OD by 1mm thick seal rings for 12 cents each.
If you want to see a dimensional drawing of the DIN 910 plug, go to http://www.wiberger.se/templates/din910.htm The M10 x 1 plug is the first item in the table. You can look at the DIN 908 plug by changing the address from 910 to 908 and resending. Thanks.