Just finished replacing the starter motor on my '89 240 (329,000 mi). I did a search on starter motor replacement and decided to try the long extension,universal and socket method from underneath. Tried everything including a breaker bar with a pipe and finally a 1/2" drive impact gun. The bolt would not break free. I gave up and decided to approach it from the top. The bolt head is 18mm but I didn't want to modify my "snap on" brand wrench. I took an inexpensive 3/4" combination box end wrench and cut off the open end. Then I was able to slide a piece of pipe over the wrench and get some leverage. There's not much room to swing the wrench but I was able to break the bolt free with one quick pull on the pipe. I backed the bolt out completely using a flex head combination "gear wrench". These "gear wrench" fine tooth box end ratcheting wrenches are a great tool to have in your roll-away. You can get them on sale at Sears now and then. The entire job took less than an hour. I did remove the entire snorkle from the air box to the throttle body to get better access to the solenoid wiring.