Die Hexe Motometer Repair

Die Hexe has been a bit jumpy lately. More specifically, her speedometer has been fluxuating at various speed making it next to impossible to get an accurate reading on speed. The go-to remedy from searching the past archives on this topic seems to be replacing the speedometer cable with a new one. After lubricating the existing one, and then buying a new one, the situation remained. The next step (at least in my head) is to take my motometer apart and see what there is to see.

Anyone thinking this repair should reconsider. Thee general concensus is to contact any of the fine folks listed on the 5united Speedometer repair site - in particular Terry Vrla. That said, I'm short on cash at the moment and as such, wondering how far down the rabbit hole I can go. Whatever Terry is charging can't be enough. This is a painful and time consuming proceedure and I still have no idea if this will work in the end. You've been warned!

The nest

Just in case I forget how to put this rats nest back together.

The take-apart

Just in case I forget how to put this all back together

The culprit

Broken pivot on motometer speedcup. Apparently this is a common problem.

The cleaning



The take-apart take-two

I eventually figured out how to remove the speedcup. Overall it was easier than I thought, but still a very difficult operation. Remove the needle by holding the speedcup and twisting (gently) the needle clockwise to loosen the friction fit. Carefully remove the brass pin which holds the hairline spring in place. Gently, slide the brass insert off the speedcup and now you have your speedcup free of the speedometer. Careful not to loose any the pin, spring, or teeny-tiny washer!

The solution?

I need to replace the 0.7mm pin that has been sheared off. To do this I need to drill this out for a new pin. To drill this out, I need to shear down the remaining pin to ensure an accurate drilling. My initial thought was to chuck this on my Vicmarc lathe and, with a flat diamond head, plane the speedcup's sheared pin down. While my Vicmarc is a fantastic mini-lathe for wood, it seems clear I'll need something far more precise to take this to the next step.

The solution, take-two

After trying to get a couple of local watch repair shops interested in helping me manufacture a pin, I resorted to looking for a speedcup replacement. Thankfully the folks at Re-Psycle BMW helped me out. Next steps - re-assemble!

Ready References

The following is a set of resources which I have found useful related to speedometer cable lubrications and / or replacement: