Beck TD, Part 17: A Speedometer That Actually Meters Speed

Here's a little side trip from the recent brake work - getting the speedometer to work. Beck TD came with a cable sheath, with no cable inside, that I presume was the original stock MG part. It would connect to the speedometer, but not the transmission. On the Volvo Engined MGs group on Yahoo, Charlie Baldwin posted that he had found a company in British Columbia, Vintage British Cables, that could make a custom cable to mate the Volvo transmission to the MG speedometer. Charlie ordered one, and I did too. Mine was 68.5" long to match the MG cable I had.

Of course, with Beck TD it's never straightforward - the connection point for the cable on the transmission was mangled, looking like this:

It turns out that connection is part of the speedometer gear. I asked Volvo parts guru Joe Lazenby if he had one, and he sent one complete with housing. Unfortunately, the gear itself was different, with 13 teeth instead of 16 like mine, and the teeth "leaned" the other direction.

However, you can see on Joe's gear on the right how that connection should look. I looked further on the web, and found what looked like the right gear at the Volvo Parts Store online, but wasn't willing to spend 80 bucks to buy it and have it shipped. I resolved to try to fix my old gear shaft.

While pondering both my gear and the one Joe sent, the light bulb finally came on and I thought, "Swap the gears." I made a little brass mandrel to press the yellow gear off my damaged shaft, and used a benchtop arbor press to remove it:

Worked fine, so I did the same process on Joe's gear. Now I had a good gear and a good shaft, and needed to press them together. But I already knew that the fragile end could be damaged! I didn't want to push on that, so I drilled the same mandrel to have a 1/4" hole deep enough to seat the mandrel on the solid shoulder of the gear.

Here's the fragile end I was protecting (left) and the mandrel seated over it (right):

One more push on the press, and I had a good looking gear:

I put everything back together, refilled the transmission with gear oil, and gave it a try. It works! That is satisfying...

Continue on to Part 18...