Frozen Speedo problem-need advice - PeachParts Mercedes-Benz Forum

showme · #1 01-31-2010, 03:35 PM

We bought my wife's 81 300D 3 years ago with a non-functioning speedometer. The PO told us it worked for his wife until a severely cold morning, and quit working when she took off for work one morning. I bought a new cable, and finally installed it last winter, and it's worked great until a few weeks ago. On another frigid morning, my wife went somewhere, and the speedo\odo is not functioning again, so I'm readying myself to install a new cable. Here's my question...
Last time I installed the new cable, I noticed there was a rubber boot "cup" that installs over the connection at the tranny. I surmised that the boot got water in it, froze solid and the cable broke when the car started to move, with the ice filled tranny rubber being the culprit. Is there anyone who has figured out how to stop this freezing of trapped water (or whatever it is) at that point? Would drilling weep holes in the boot help\hurt? Would leaving the boot off altogether be a bad idea? Or is there some sort of non freezing substance that I could fill it with? Thanks for any suggestions. I don't want to have to replace a $47 cable every year when the temps get cold.

Aquaticedge · #2 01-31-2010, 03:51 PM

could be the grease in the cable got stiff enough depending on how cold it got. Stranger things have happend

okyoureabeast · #3 01-31-2010, 03:54 PM

My car makes this weird noise from under the dash when the car is cold. I figured it had something to do with the spedo cable's lubrication getting hard in the cold.

Would dripping some ATF or gear oil down the line fix the issue?

showme · #4 01-31-2010, 08:44 PM

Not sure. But the cable was an OEM part, and the old, broken one I took off the first time was a clean break at the transmission connection. I would have thought that the rubber is there to keep everything out, including water that might freeze. The sad part is that the cable had a two year warranty- and I waited a year and a half to put it on.

Anyway, if anybody knows of some sort of non-freezing lube that I can put on there, let me know.

Why did I wait that long?? I didn't want to put it on and find out it was something more expensive. It's one of those "just-in-case" quirks that I posess. I could have kicked myself after I finally did. One of the easiest repairs I've ever done, and we drove all that time with a Garmin Forerunner strapped to the steering wheel to know the mph. Anyway...

bustedbenz · #5 01-31-2010, 08:53 PM

You may have a perfectly good cable but a slipped gear, etc, in the speedometer itself.

showme · #6 01-31-2010, 09:43 PM

Ahhh. Hmmm. It seems like I'd hear lots of clattering upstairs if that were the case, but you never know! (At least I won't be surprised if I find that, now). But, knowing the history of the first break, and seeing how the circumstances are akin to the second break, I'm afraid it's back under the beast, anyhow. But thank you. I will remember this when I find out that you're right!

bustedbenz · #7 01-31-2010, 09:46 PM

Quote:

Originally Posted by showme

Ahhh. Hmmm. It seems like I'd hear lots of clattering upstairs if that were the case, but you never know! (At least I won't be surprised if I find that, now). But, knowing the history of the first break, and seeing how the circumstances are akin to the second break, I'm afraid it's back under the beast, anyhow. But thank you. I will remember this when I find out that you're right!

I may be wrong, but when I got our 240D, neither the speedometer nor the odometer worked. After a new speedometer cable, the speedo worked but the odometer was still slipping. Did the dieselgiant odometer fix, and it worked. I'm just thinking maybe it's something like this.

However, it may be that there are no other linkages between the cable and the speedometer gauge part of the unit. If that's true, then mine was an invalid guess. It may be worth dismantling and taking a look, though.