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omne207 12-11-2007 01:07 PM

300d speedometer ?
i was diving to day to go get a cup of coffee when my speedometer/odometer stopped working.
i would assume i need a new speedometer cable can any one verify that i may be right.
iu am going now to see if i can order one at the parts store up the road as well as get a bolt i need and some wipers but it would be a big help if i knew for sure that that is the problem

KAdams4458 12-11-2007 01:34 PM

Without knowing specifically what model year your 300D is, no one can even tell you if the car is equipped with a speedometer cable. Please, what year is your car?

omne207 12-11-2007 02:30 PM

sorry it is a 79

KAdams4458 12-11-2007 03:01 PM

It's no big deal, but thank you for the info. I can answer this one. Your car does use a cable. Checking it is fairly simple, but can be a little frustrating for some people.

Usually, the cable insert is indeed the weak link. Frequently, one that is about to die will cause a jerking, unstable speedometer needle, as even a noise, frequently a clicking that increases with speed.

Honestly, the best way to check them is to slide them out of the sheath. but it's not always possible to do so easily. By pulling it out, a complete inspection can be made from tip to tip, and it's the only way to be sure there are no fraying strands or kinks anywhere.

On my 300D, I actually removed the cable from both the cluster and the transmission, removed the cable from the sheath, and cleaned both completely with brake cleaner before applying lube and reassembling them. (Preventative maintenance, and very possibly overkill.) At least now I know that it's in perfect working order.

I suspect there may be a thread or two on here with great instructions for accessing the cable from both ends, which is important should it be broken in the middle somewhere. My memory is a bit fuzzy, as I did it months ago, or I'd attempt to walk you through the process. I'll see if I can find a link or two.

omne207 12-11-2007 03:07 PM

thank you
i belive that would be the problem as it was doing that jerking thing i was not sure why i need to take apart the dash soon any way to install an acc upgrade kit. i was going to check all the fans and cables while i was doing all that.
then the speedometer quit. ahhh always something. but like you said at least you know everything works after that and properly.
thank you so much for the answers

KAdams4458 12-11-2007 03:14 PM

Here's a recent one with a good photo that shows roughly where the cable is located at beneath the car where it attaches to the transmission. Hopefully, yours doesn't look like this.

Here's a concept. Looking at the cable to see if it turns while driving... Brilliantly simple. Maybe worth a try.

Warning, it appears there may be more than one style of cable. I didn't know that until just now. :o

So, Maybe try out driving with the cable disconnected and seeing if it turns would be a good place to start. I've never tried it, so I can't say how difficult it is to watch the cable end and drive at the same time, but it seems like a decent, quick test.

fdanielson 12-11-2007 06:51 PM

Speedo test
If you do pull the instrument cluster you can stick a small screwdriver or square drive bit in the socket where the cable fits on the speedo. Turn counterclockwise and watch for the odometer to move. You can see the how the gears mesh and activate the odometer mechanism. It's not too hard to see if they are turning or not. If you have a speedo cable insert handy chuck it in your reversible drill and crank it up counter clockwise. Start slow and build speed just like in the real world.

omne207 12-11-2007 10:50 PM

sweet i was planning on taking it apart in the morning when the snow stops and it will be easier to keep things open i shall try driving it test and see if it helps out at all. if not i have to wait for a week to get the cable to replace it.

omne207 12-12-2007 03:27 PM

pix of cable
2 Attachment(s)
i pulled the speedo cable off from the reader and drove it like suggested didnt watch the cable as i was driving home but held on to the end to feel if it spun.
the cable itself still works to the best of my knowledge as it spun in accordance tpo my driving the car. the pin on the end that is removed is my question it looks like it may have broken at the top
the speedo does not move with a small screw driver in the hole the speedo came from

vstech 12-12-2007 03:53 PM

the first pic looks correct, the second pic is surely a broken end... is the other end still in your speedo? which end is which?

omne207 12-12-2007 04:02 PM

the other end apparently is stuck up in the dash part of the speedo.
both those flix are of the same end inside the car behind the dashboard

KAdams4458 12-12-2007 04:06 PM

Bad news. That part shouldn't break, as it's supposed to stay attached to the speedometer. What you need is a speedometer, which is obviously a lot more expensive than a cable. That's the part that was broken on the original speedometer from my car. Besides mine, yours is only the second one I've seen develop this problem. It's time to go salvage yard shopping. I'm sorry.

On the bright side, your speedometer has a few internal parts that I wouldn't mind having, so at least it's worth a little something to someone. I'm probably the only DIY'er brave enough to dive in to speedometers. Once you get set up with a fresh working one, I'd be happy to keep the original out of your nearest landfill.

omne207 12-12-2007 04:11 PM

damn i was afraid of that. well at least i know if you know of a salvage yard that would have one let me now i have called three or four different ones in nm and there is not a single mb diesel in there. i will gladly save the parts for you.
thank you for your help
well i take it back there is one guy but hes an ass i learned how to solder cause the dude broke my blinker when all i needed was a lens cover. i would not have been so mad if he had helped fix it but he just took off so he does not deserve my cash ever again.

KAdams4458 12-12-2007 04:41 PM

Well, I'm always hunting for bits and pieces. I know a few place around here have them, but the price is generally capable of producing knots in the gut, if you know what I mean. I can ask Benz Friendz when I call over there later. I've been meaning to ask him if I can get a slight discount for buying ten or fifteen injector cores instead of just five. :)

Sometimes, the chain of Pull a Part yards around here have Mercs. They're usually pretty crappy, and get picked over hard and fast by the natives, but they do sell speedometers for $6.50 plus tax. I managed to not only pull one for that price a while back, but also escaped the angry natives that felt they were more deserving of the parts because they had seen them the day before and had returned for them only to find me unbolting them.

I'm warning you, though. If I find you one and get shot over it, I'm charging you double what it cost me! :P

omne207 12-12-2007 04:54 PM

oh of course. i was soo hoping for it to be the cable much easier to find from my 20 minute search. cant even buy them new if you wanted to
thank you.
seems to be the weird luck o the irish. i must have pissed off a leprechaun in some life

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