'72 250C...VDO Instrument Cluster Squeal - PeachParts Mercedes-Benz Forum

curtis61387 · #1 02-01-2010, 08:03 PM

Hey all, I have a high pitched squeal coming from my instrument cluster. This just started out of no where the other day. It sounds mechanical and isolated to the speedo/odom area, as if maybe the mechanical gears in there are broken and spinning. The odom has been broken since I have had the car, the speedo works as it should, I pulled the the cluster out enough to detach the cable that runs into the back of the speedo/odom and that eliminated the squeal but I was left with an inop speedo. Not ideal, but better than listening to my dash squeal like a pig.

Any ideas of what the squeal is? Also, is the speedo reading produced mechanically or electrically? I Would like to at least have my speedo back with no squeal but ideally would like odom/speedo back up and running.

Thanks,

Curt

JiveTurkey · #2 02-01-2010, 08:10 PM

Lemme guess...
http://www.youtube.com/watch?v=F1ZhD6T0yVw

It comes from a dry bearing or something in the speedometer. I call it the Broken Blender Noise of Death. The speedometer has a cable coming out of the back, it's retained by a knurled nut that surrounds the cable.

JiveTurkey · #3 02-01-2010, 08:11 PM

Palo Alto speedometer can rebuild em I think.

curtis61387 · #4 02-02-2010, 01:36 AM

Somehow I knew you would know the answer to that question Jive. "Broken Blender Noise of Death" is exactly the right description for the noise. Still cant figure why it would all of a sudden start like that, it happen to be on the coldest night we've had down here, I drove it to work (no noise) and parked. Overnight it hit 20F and in the morning when I went to leave work there it was. Oddly enough, the next time I went to drive it there was no noise, but upon further investigation...the cable had become unbolted in the back of the speedo. How this happened...I'm not sure. I might try shooting some WD-40 up into the speedo where the cable attaches and see what that does. Does anyone know if these clusters are available new or refurbished somewhere?

Mike D · #5 02-02-2010, 06:56 AM

No WD40! It will make matters worse. Any goop in the bushing casing will get worked into the odometer gear cluster and really foul things up.

cadurning · #6 02-02-2010, 06:59 AM

Ebay is a source for a replacement speedo. WD40 is too light to be long lasting. I have used sewing machine oil to lube the shaft in the speedo with success. The wife will have a bottle od sewing machine oil that has a long needle. Using that applicator you can get the oil where it needs to go. While you're at it lube the speedo cable with a light aerosol grease like LPS. An aerosol grease can be sprayed between the cable & housing and it will wick down to the bowels of the cable.

mak · #7 02-02-2010, 09:47 AM

sewing machine oil seems perfect . somehow wd 40 dries up after a while .Wonder if there is a dedicated oil for blower motor bushes etc.?
mak

250 Coupe · #8 02-02-2010, 10:28 AM

I used to know right away when to keep an eye out for black ice in both the Coupe and the 450SEL.

I used an oil similar to sewing machine oil that is sold for use in Magnum 300 aquarium filter motors. They go on and on about how wonderful it is for the bushing motor in the pump. Silence for two years now.

Michael

JiveTurkey · #9 02-02-2010, 03:35 PM

Some dextron III (reccomended by some kind soul on here) shut mine up for a little while, but my speedometer had absolutely NO pattern as far as when it squeeled and when it didn't. I'd be able to drive for 100 km sometimes without a single squeek and then it would erupt with that spectacular noise.
It was so random it almost became comical. It would squeel on hot days and on cold, and on almost every combination of speed / odo count / trip odo known to man. Eventually I just put a little Dex III in there and it was silent until I started the Restoration at the beginning of this year.

curtis61387 · #10 02-02-2010, 07:40 PM

Yeah, mine just started and has already scared the piss out of me more times than I care to mention....I'll be driving down the road thinking that its fixed it self some how, as these old cars seem to do, only to have it start squealing randomly sending me through the roof! Where can I picked up this magical Dextron III or sewing maching oil?

JiveTurkey · #11 02-02-2010, 07:49 PM

Dex III is automatic transmission fluid, I used the Advance Autoparts store brand. I really hope it's a lasting fix for you. The squeel is one of the things that led to me taking my 250 completely apart for restoration. Funny how those things happen eh?

By the way, I TOTALLY know what you mean about thinking it has "Fixed itself" because mine stopped making noise all through the month of november when I enlisted her for daily driver duty. Does your change pitch at all? Mine (sometimes) would be silent, or very low and "growling" until about fifty kph when it would decide to really start making that high pitched noise from hell.

cadurning · #12 02-03-2010, 07:12 AM

Sewing machine oil and the applicator can be found anywhere sewing stiff is sold such as; Target, Walmart, Sears, Michaels, Bed, Bath, & Beyond, yardage stores, sewieing machine stores, small appliance repair shops, almost any place where women shop, and eBay.

http://cgi.ebay.com/4-OZ-SEWING-MACHINE-ZOOM-SPOUT-CLEAR-WHITE-OIL-OILER_W0QQitemZ250476345632QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a518db920

curtis61387 · #13 02-03-2010, 08:22 PM

Thanks for all the info guys, I'm going to try the Dex III first thing tomorrow and will post my results.

JiveTurkey · #14 02-03-2010, 08:49 PM

Best of luck Curtis!

curtis61387 · #15 02-10-2010, 01:02 AM

Good news, the odom squeal is gone! I actually found some oil around the house made to oil up the blades on a pair of hair clippers. I found this to be similar to the sewing machine oil and figured id try it first before making a trip to the auto/hobby store. Thanks for all the help, I can now ride in peace.