VDO speedometers, like others of its ilk, are fairly delicate little buggers. I treat 'em like they are a big watch, and have built a number of special tools to EASE 'em apart and EASE 'em back together again. I use the dial indicator to get measurements BEFORE I take the speedo gubbins apart--I like to put them back together at the factory settings.[Ignore the pliers].
The red tools are the special ones. At the top, the press to press the main odometer shaft back into place after the bad odo gear on that shaft has been changed. Immediately below, to the left, the puller for the speedo needle. To its right, a puller for the wee brass gear on the main odo shaft. Two mount fixtures are below, and I use them to hold the speedo frame firmly in place while I change out the parts.
This is the back section of a Sonett III speedometer. The round "drum" in the center is a very small permanent magnet that makes the speedo needle operate. To the left of the drum are a set of plastic gears that operate the odometer assembly number wheels. I check all this stuff and replace bad parts, and then lube all the moving parts.
The pointer indicates the main odo shaft. On the table to the right is a new odo drive gear that I am about to install. This little sucker fits to the extreme right end of the TOP number register. I have already removed the bad gear.
This is the wee press that I built to press the main odo shaft back into place. I press the shaft into place so it has the same clearances on each end as it did before I took it apart. Note that the new odo drive gear [the white one on the right end of the register] is in place.
I've adjusted and lubed all the internals and its going back together. Note the use of one of the [red] stabilizing stands. Just a matter of putting it all into the case, cleaning the glass face, and snapping on the chrome retaining ring.
As I said in an earlier blog, VDO speedometers are no big mystery to me. If you have one that only "odo's" when it feels like it, it may be just like the one you see in these pictures. I can change the bad stuff inside, clean, lube and adjust the rest and PRESTO! A speedo good for another 100,000 miles. AND....I can do it for a whole lot less than the "regular" speedo shops charge. Give me a growl and lets talk!
City Car Design
7 years ago