Car stats: 1987 260E

Hello all. So finally I have some free time to work on the clicking noise speedo. Basically, the trip odometer is stuck and no longer count. However, it makes a click sound every 100 meters or so. It drives me nuts, so I have ordered some gears off ebay and wanted to take a crack at it. I have removed and disassembled the unit and actually pried the needle off, and popped off the black plate with the miles-range label below that.

What I found after stumped me, there is this copper(or brass) coil like spring that sits just below the needle and it looks very fragile, I don't know how I can work beneath at the gears without removing this coil. I am pretty sure if I pop off this coil, I will never be able to put it back.

So how do people go about working on replacing the speedo gear on a W124 ?

I don't have a camera handy so I just found a similar photo off google, which refers to the same copper coil. Actually I think it's the same speedo.

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