Friday, September 28, 2012

Sporting My Speedo (speedometer, duh)

Let me make it very clear before continuing will not see me in a speedo.  With that said, I'm sure I will lose a couple of readers, but for the rest, here is what little bit I did to the speedometer.
The speedo that was in this MB's dash is a wartime correct Motometer speedometer.  I know this because it said "Motometer" on the backside.  Wartime correct because it has the trip meter and 60 MPH max.
When I pulled it from the dash, I could reset the trip meter without any issues.  That was a good sign.  However, the negative part is that it appears that somewhere inside, something is hindering the the gears from spinning.  The overall condition looks good, so I'm hoping there is just some hardened gunk jamming the clock-like gears.
It all begins with prying the bezel away from the canister and then removing a few token screws and such from the rear.
As is like the day I pulled it out.

Using a paint can opener to begin prying the lip away from the canister.
Patience and a few rotations around the loop will make it nice and neat.

The backside.  When removing it from the dash, I broke the upper part of the mounting screw off. 
That was an upsetting moment.  (broken mount at the 8:00 position)

This is the order that the small parts go for the trip meter reset switch.

Bezel and glass have popped right off.  Note: be weary of the needle and the 10 and 20 marks...
...they are painted with some sort of radium so they will glow at night.

The number dials look great, as do all of the internal gears.

Nothing particular, just pictures to help me remember where things go...if I need to disassemble further!
Check out the small brass plug at 3:00 o'clock on the large threaded shaft at the bottom of the mechanism. 
This is the oil hole and will come back into play in a few moments!

I wonder what the "L" was for?

Internally, it looks very clean.

Watch makers hand puller in place to remove the needle.
Originally, I had grandiose thoughts of removing the needle and then taking the entire mechanism apart for a deep, thorough cleaning beyond the magnetic housing.  I could not get the needle to budge and I had read too many horror stories of needles snapping off the shaft.  I didn't have the courage to do anything that I felt was excess force to remove it.  I stood down.  I hope Aramis in Croatia isn't too disappointed in my lack of courage.
Instead, I removed the brass plug on the rear side and was able to spray a little carb cleaner in there and pull out (with a dentist's pick) little bits of dried greasy gunk.  This is the oil hole and it was supposed to have a wick in it.  I did not see a wick anywhere and it wasn't like there was a whole lot of room for anything to hide down there.  I could now use my thumb and forefinger to spin the mechanism that controls the needle.  I let a few drops of 3 in 1 oil go down the hole and the gauge began to spin without any resistance.  I then inserted the end of a broken speedo cable into the rear hole and could spin the needle with ease.  I'm hoping all it really needed was some fresh oil.
The gauge was then carefully reassembled.  I cut the shank off of another screw and welded it onto the broken wing nut stud and filed it down so it could be used again.  The gauge was then fitted with the speedo cable and secured in the dash.  Before attaching the other end of the cable to the transfer case, I spun it for good measure and watched the gauge reach 50 MPH.  Sweet. 
And do not fret; the cable was thoroughly cleaned after picking it up off of the road from the other day (the lost jeep part) and graphite powder was reapplied before running it though the sheath.
The dashboard with all original working gauges!
Well, at least 3 out 4 work...I don't have a gas sending unit to check the fuel gauge.

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