It may have been just the age of our 280 (75) but removing the tank outlet hose, so we could remove and clean the tank, proved to be a major project. First tried a crowfoot on an extension and the impact wrench and got nowhere. Ended up cutting the hose off so a deep socket on the impact could be used. Seriously thought the bottom of the tank was going to be damaged.The hose fitting and the tank fitting were dissimilar metals. Guess MBz never heard of anti-sieze compounds. Anyway, POR-15 makes products that turn tank cleaning and sealing into a DIY project, which is what I had planned to post, not whinening.