I finally removed half of the interior and the tunnel cover to trouble shoot the speedometer, which has a tick/jump throughout the speed range. The tick remained with an electric drill on the transmission end of the cable. I then verified that it was the speedometer by attaching a spare speedometer to a spare cable to the right angle drive…the spare unit worked fine laying on the seat in the car. So now I need a specialist.
I’d like to retain the original case (moified with LED strip lighting), face, and odometer which displays the original mileage. I guess an option is to turn back the odometer on the spare unit and then transfer all of the mechanicals into the original case…?
Anyone have a contact for a good speedometer specialist?
Thanks. I forgot to mention that I used two different (one new, both freshly graphite lubed) cables on the original speedo (on the road and with the electric drill) before substituting the spare speedo. It’s for sure the speedometer.
Well, that’s exactly the problem I had, and it was the small gear driving the odometer that had a small crack in it, just enough to resist turning so the magnets would release and regrab with a tick in the speedometer. You can easily check that by taking the speedo apart, removing that gear and then spinning the speedo with a drill to make sure it’s OK. Then, you can replace the gear with the one from your spare speedo. There are so many assumptions in what I just said it’s ridiculous, but hey, it worked for me. Or just take the spare speedo apart, turn the odometer to where it needs to be and use that one.
I’ve decided to use innards from the spare speedometer in the original case, which is modified with LED lighting. The spare functions properly, but the odometer reads about 15,000 miles more than the original. So I want to roll back the spare to make it “correct” for the restoration. Anybody know how that is done? Is it a speedometer shop secret? Maybe swap the odometer wheel mechanism? I guess I could put it on a drill and run it forward for a couple of weeks…months?
No secret. Remove the glass then push each number wheel slightly to the side to disengage it and turn til you have your desired number.
Can even be done on the dash. Back in the day it frequently was, certainly over this side of the pond.
Would not make much difference to many cars (mine) as it has already gone round twice. Mileage after Monday’s little jaunt 213,800. The 2 doesn’t show, of course
And while the Speedo is out, lubricate the milometer mechanism, especially the tenths ratchet. This was the cause of my jumpy needle and accompanying tick.
I just tried this on the spare speedometer. A word of caution. The number drums can indeed be turned back, but they cannot be turned forward. And they also can easily catch an adjacent drum and turn back both numbers. I did exactly that and undershot one of the target big end numbers. So I decided I’d just keep backing up and approach my target number from the other direction. Wrong! Once the drums hit zero, they are blocked from rotating in either direction except via the normal gear mechanism. By the time I got through jacking with it, I ended up with a zero’d out odometer…definitely not my objective.
Now, you can use the little gear at the end of the number drum as a thumb wheel and advance the total one mile at a time. In my case that meant 64,322 revolutions of the little gear…or hook it up to a drill and spin it back up mile by mile (about 1200 hours on the drill as it will only make 45 mph in reverse). That would cost me a couple of electric drills, a worn out speedometer cable and burned out gears in the speedo head. My new approach is my old approach…send the original unit to a pro and tell them to fix the tick. (Well, maybe I’ll trying lubing the original odometer drums and gears first…let’s see if I can muck that up…)
