Posted by David Sherman on Thursday, June 28, 2007 at 13:49:49 :
In Reply to: Re: M-37 gas gauge question posted by Robert N. on Thursday, June 28, 2007 at 09:28:27 :
No, I mean that I add a flexible coiled wire to provide a positive electrical connection between the arm and the mounting bracket, through that wire. I'm not sure exactly what kind of sender an M37 has in it, since mine didn't have the original tank, but on other rigs the way it works is the terminal on top of the tank goes to one end of a resistive element and the wiper which moves against the resistive element goes to ground via the wiper arm, the pivot point, the mounting flange, the tank, and the chassis. Out of this whole circuit, the least reliable connection is the pivot point between the wiper arm and the bracket since it's just basically one piece of metal laying lightly against another. After decades of corrosion, build-up of varnish and lead, and so on, the connection ends up being not so good. Rather than keep messing with cleaning it or swapping out senders that work for a while and then get flaky, I've solved the problem permanently by soldering the flexible wire between the arm and the bracket. I'm not sure why they didn't make that part of the original design. The point of coiling it is so that no part of it bends very much, so that it's less likely to eventually break due to fatigue. The point of soldering it on at both ends, of course, is to make sure that there's absolutely positively a permanently good electrical connection.