I probably broke because the line is plastic and gets very brittle. The right way to fix it is to buy the fitting and the plastic line from a dealer. You need to pull the instrument cluster out to attach the line to the gauge. I had to do this on an SL and it was around $120 for the parts.

You can try a compression fitting, but I suggest one with a sleeve that fits up into the line to reinforce it from breaking again. The trouble is, the plastic line is so stiff and hard from heat and age that it won't compress to allow the fitting to seal.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe