My husband is trying to do a "minor" tune up on our 1990 740GL wagon. We can't remember changing spark plugs or wires since at least 1992. Anyhow, he can't figure out exactly what he needs to get the distributor cap off. There is very little room to work. We saw somewhere on the Brickboard where you need an 8 mm wrench, I guess he needs a little more info than that. If anyone has a good description of what tool he should use, we would appreciate it. The car has 223,000 plus a few, miles on it. I guess it's a little overdue a tuneup. Thanks.