2 Odometer problems/questions - NOT typical shaft slipping - 450sl

[supercanuck]

Last night I started taking apart my odometer b/c it was finally at the point where it would not longer work.

I used Diesel Giants tutorial and went through with no problems, and when I finally got it open I realized that there was no bushing/collar that was holding the number shaft on. After looking at some of the pictures on his tutorial, it also appeared to me that the shaft in my odometer may be too short, as it barely pokes through the other side of the odometer and doesn't look like there is enough sticking out to even put a bushing/collar on. When I measured the shaft, it was 55mm starting at the very bottom of the brass gear, where the shaft goes into the gear.

So, question #1: Does anyone a) know how long the shaft is supposed to be, b) is it possible to buy a replacement shaft if mine is too short, and c) is it possible to buy a replacement collar/bushing?

I then noticed that the numbers were turning fine, until the trip odometer hit the .9 mark, when it would get very tough to turn. I assume this is what was causing my problem...when it got to this point and couldn't turn by itself, then the gear on the main odometer started slipping, as well.

Question #2: Does anyone know what may be causing this 1/10 mile wheel to be getting stuck? How can I fix this?

Thanks!

[gsbaxter]

colder outside. Stops at .9 also.

[Mike Freeman]

Your odometer dosn't have the brass bushing;the first gear on the right on the upper row is Pot-metal, The shaft is supposed to be a press fit into this gear.
When a digit is about to roll over to 0 it is also turning the next digit by 1 which requires more power through the already slipping gear, When it's cold the metal contracts a little and allows more power through the gear.
Mike

[bpaz_ph]

When I did mine I just crimped the shaft end with my long nose plier before pushing it in the bushing.

[gsbaxter]

So do I just crimp it, or glue it as in the spelled out repair guide on here?

[bpaz_ph]

Your choice. More like knurl than crimp. Squeezing the shaft end produces sharp edges that when forced in the bushing should be strong enough to last for a while. The problem is, I don't think i'd be able to slide off the number wheels anymore.

I'd recommend glue since if you have to take it apart again all you have to do is clean it off. Just have a strong enough glue to hold the parts together. And if it doesn't hold, you still have the knurling option.

[ichbineinekrous]

Ive been having this exact issue with my odometer, every time 9 tenths of a mile rolls around there is excessive resistance. I've had the cluster out and apart 3 times now and I havn't glued the brass gear to the shaft because I have always been unable to get it to slip when holding the speedo in my hands. I used what I consider to be an amount of force much greater than what the plastic worm gear could apply, and the trip odo gear is very solidly attached to its shaft.
I did seem to have fixed it for a couple hundred miles the last time by slightly tightening the slotted brass bolt at the left end of the trip meter readout, but yesterday it was stuck again at 216.9. The reason I tightened said screw was that the slippage seemed to be occuring between the tenths and ones digits and tightening that screw does bring the digit wheels closer together. Anyone reading this old thread with additional info or a similar problem would be greatly appreciated. Thanks.

[ctaylor738]

Me too. I put 74 miles on the odometer while experimenting last night.

This is on a 1977 450SL that sat for six years. The .9 comes up on the trip odometer and sticks, and the odometer stops turning. I turned the black gear that drives the trip odometer with a small screwdriver, and I can force it past the .9, but it takes quite a bit of force relative to what it takes to turn the gear normally. You can feel it go past the .9. This happens maybe one out of three times, the other two, the transition past the .9 is quite smooth.

So I think something is hanging up, rather than the gear just slipping on the shaft.

Any ideas?

[supercanuck]

...I think I finally got mine fixed a while back, and I tried something I hadn't read about in the form, which seemed to help. I got the point, like you said, where the shaft wasn't slipping, and it was turning fine, but when I put it back together, it would get caught on the .9.

When looking a little closer, it looked like there was too much pressure from the spring on the trip reset meter, which was causing it to stop when it got to the .9. I took my dremel and cut a little bit of the spring off, enough that it still worked but not too much so that it was pressing too hard when assembled.
Seems to work fine now.