A good rule of thumb is to clean as much of the corrosion as you can. I don't know about the length of the bell but as long as it clears everything it should be OK. I made new gaskets for my 38 horn using regular gasket material you can buy at any hardware store. The mechanical workings only work one way. It took me TOO long to find out mine wouldn't work because I turned one part around backard when reassembling it. It may be a little late since you've already got it apart but make sure to keep track of everything's position in relation to everything else as you disassemble. If you could post some pics it would help with specifics. Someone may post that knows more about your specific horn than I do. Good luck.

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