Odomoter works only part time
 

For the last few (dont know exactly how many) miles, the odomoter works some of the time, sometimes not. The speedo works fine, I know how fast I'm going, just not how far. Is there something inside the gauge to prevent worse damage, or is it time to replace the gauge?? 231,000 miles on car/gauge. I have another (a few) gauge(s) I can replace it with. How much hassle/is it possible to reset replacement gauge 'miles' to old ones readings? (I can figure 25 (mpg) times gallons purchased to figure how many miles approxametly since odo quit on me, , , ,

-c-

speedo
 

You need to check out information on the pot gear in the speedo that needs fixing to the spindle .The drive is ok to the head, but miles are not working .This is afer the trip button is pushed in while the car is on the move ,never do this it damages the gears in side .I did mine last year you will have to pull out the console .Remove the speedo head and fix the gear with glue so its rigid on the shaft . Google it the tutorial i used was from Diesel Giant site. Someone on the forum will put you in the right direction for information step by step .I am sure it is on here thats the place i had my information from..Take a look up top of the page at TECH INFO ^

Optimusprime is right, its most likely the gear.

What happens here is that metal gear on the right of the odometer section looses its grip on the odometer shaft.

Pics here are specific to W123, W124 is similar but a lot easier to do.

http://i.imgur.com/qPShQyWl.jpg

I would strongly recommend replacing the gear with a new one. They can be had for $25 or so.

Personally I would not resort to gluing it. I have not had a lot of luck with glues over the years.

The glue may fail at some point in time and you'll be here all over again. Why not fix it right while you have it out? The near gear will outlast the car pretty much!

http://i.imgur.com/VdgdDm0l.jpg

I use to buy my gears at www.carradio.com

These go wrong after the trip counter button is pushed in while the car is in motion and the gears mis match in side .I used a drill to hold the gears and number drums in place plus tape across all the numbers .If they move it takes ages to get them right again , this is the one main part to remember . Push the drill in [the same size as spindle] I then put groves in the spindle and super glue.to secure it .And be very carefull lift the pointer off .Take pictures of it, if you can , and make sure numbers are the same when your finished. I was very lucky , a friend sent me an old speedo to operate on .So i knew the ins and out of the job when i started to work on it if you want help it is all on this site .in tech info above...

Yesterday I finally found the box of speedo/tach/gauges. Have 2 speedos, one is marked 116, the 123 marked unit is very close (total mileage) to whats in the car, and, the numbers are much easier to read, I might just swap 'em out. There is a shaft above the numbers's shaft, with indexing (?) gears on it, can this be removed to reset the actual numbers read??

This would certainly simplify things, , , ,

-c-

Check this job at DIESELGIANT . Its for a w123 but close enough .When you remove the speed pointer lift it over the stop and mark the dial where the pointer stops and put it back in the same place or speed will be out .See pic next post

Be vigilant with the snail spring on refit ..Take pictures of it before you start.And you will be able to check it and see that all the numbers line up to your picture.. Sorry once again picture failed to load up.

Its the shaft that moves out of the green pot gear.You have to push in a drill bit the same diameter as the shaft to hold all the numbers on it together. As the shaft comes out you rough it up with a smal file so the super glue will stick to it in the pot gear. If you do opt out, and feel the need to fit another speedo head ,you will need one with the same number on the speedo face. Numbers --------VDO make.

The 123 marked gauge is from an '82 300d, my car is an '83 300cd (both turbo)

On the 116 marked one it appears the only diff is the bezel (plus some tabs for mounting it)
The innards appear to be the same. Dont know about #'s of teeth on gears. (different ratios)

-c-

Easy to check with your old one take it out and count the gears .

Well, yesterday I finally removed the inst panel, thought I was gonna break something removing the steering wheel mounting screw. The whole 'bezel' on the panel came off while removing the panel, for starters. Took the tach & gauges units out & put them in the older panel, as its bezel was intact. Last screw I installed was to a broken off post in the panel body. Superglued the bezel back to orig panel. Put everything back in orig. Now, I have not moved more than 2-3 feet since starting. Lost one of the (8) mounting screws holding gauges in. Cleared bench, not. Swept floor, not. Magnet everywhere, not.
Found a sheet metal screw same (+-) size to replace it. Plus washer. (2 screws have funky washers, lost one of them 'natch). Moved the 'bad' panel out of the way, rattle, oh there it is/was! All back together.

In the car, I thought: I wonder if the speedo cable is the problem? Jacked up one rear tire & started motor. Thought: no inst panel. Thought NO OIL PRESSURE GAUGE CONNECTED!! Thought: OH ****. Turned off key. Realized cars vacuum has bled off. Thought: OH ****!
Here comes the oil. On my legs, on steering column, on carpet. Thought OH ****ing ****!
Held my thumb over oil line. Built up enough vacuum to finally shut off engine. Cleaned up mess. Cleaned up myself. Installed panel. Everything works.

This morning I went to the gym, well not everything works after all, panel/inst lites do not work, none of 'em.

Also, I sat on my vintage 'RayBan' new prescription sunglasses & broke off both temples, biggest bummer of all.

I'm gonna be driving my Blazer for a while, , , , ,

(Oh, yes, got the steering wheel couple 'uh grooves off, , ,)

Things have been going so well, till yesterday.)

-c-

Repaired my trip meter 3 years back now with super glue still working strong .The shaft wants roughing up with a file ,tp make a good bond.

I thought I was 'all taken care of' with the repaired odo.
Filled up with the deez' & checked the mpg.
Numbers show about 10% lower mpg since the fix.
The speedo seems to be about 10% off also. <- I know I am going faster than the speedo says, same driving speed but fewer cars passing me!

The replacement odo part was marked as "123 *****" but I have had it sitting around for a few years, dont know if it was out of 240 or 300, auto or manual. Dont know diff ratio.
How is speedo/odo compensated for (gear ratios), a gear in the trans or in the odo unit?

Everything works, just 'off', , ,

-c-

(not pulling it to check #'s) (not yet)

There are at least two different 125 mph speedometers for a w123 300D. The difference is in the speedometer head, not the transmission. The speedometer for a 1985 model 300D, CD or TD ends in the number 57.