Speedometer strip-down
Another job I've been meaning to do. The speedometer didn't like the cold! In warmer weather or after the interior had warmed up a bit, no problem. The speedo had been reluctant to climb off zero otherwise. It was getting slowly worse, even a chilly night in summer would cause it to stay on the stop. Now the trip and odometer worked fine, so the cable was still rotating the instrument properly. I suspected oil or grease inside, from the cable, thickening up with low temperature.
While I had the dash off for wiring repairs, I disconnected the instrument pod (easy) and demounted it. There were just two screws, the speedo cable and the four multi-way connectors to the back edge. The connectors have a simple plastic clip to push off the back and then they pull off.
Note above, the stain around the two grommets, which again made me think the problem was going to be an oily cleanup to do.
Here's how it came apart:
Getting the actual speedo bit out was easy, just a couple of screws. The clock face had to come off so did the needle. I was concerned about getting the needle back in the same place. If I just pulled it off, the return spring would wind back past the bottom stop to who knows where? So. I lifted the needle carefully over the stop. It could then show me where ;o) It came to rest further down the dial and I marked the spot with a small pen mark. The needle then could be pulled off and the face removed; another pair of screws.
I made a careful note of the digit positions and put the bits down in a line with "which bit faced where" preserved. The number wheels and little gears stayed on their shafts! I also took these photos to help me reassemble the thing later.
So it wasn't oil contamination after all! The stains on the rear of the pod would have been from the black rubber. The brake cleaner spray I used to clean the assembly actually chilled it and demonstrated the problem rather well. Dismantling this part was scary. It was riveted shut using alloy stubs, part of the main casting. There was no way to pull it apart without drilling these off. Oh Boy was I careful...
Pressing down the top of the can gave the needle shaft a touch of end float which it did not have before. Next out came the careful drill again, and made a screw hole through the casting. There was a handy dent in the back of the casting to start my operation off. I tightened the screws and made sure the needle was still free, then undid them, applied threadlock compound and refitted the nuts..
The famous "reverse of the above" then followed. Getting the wheels and tumblers back in line took a couple of tries though..
One useful thing I found out, was how the bulbs are fitted. They are tiny wedge type and could likely be replaced via the steering column access panel under the wheel.
As an aside - new camera last January :o) it has a good close-up feature.
JUST after I put all of this back in its proper place, the
weather turned much colder, a chilly 10 degC drop. No sign of sticking yet 
(Nor 6 weeks later either, I think this one is cured.)
Aixam