Lifetime Premium Member
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Mentioned: 3 Post(s)
Quoted: 102 Post(s)
Yes there is an access panel in the trunk. In the middle of the trunk floor you will see a plastic disk maybe 4" across. Pry it out. Unplug the sender. take out the nuts and try to wiggle the sender out. It comes straight up and will be stuck in place fairly well.
The cork gasket will need to be replaced also.
Sending units generally are gunked up. You take them apart by removing the small plastic/metal nut on the very bottom, then the metal disk, then the plastic disk, then carefully pull the tube away from the top of the sending unit. You will find a float that slides along the center metal piece (the thing that the tiny nut was screwed onto) and the float also glides along two guide wires that provide the resistance to control what the gauge shows. Be careful, if you mess up the guide wires you need a new/used one.
If it's always reading full that means it isn't sliding down, hopefully a good cleaning (carb cleaner, contact cleaner) will remedy the situation.
Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...