squeeky tachometer

[Cees Klumper]

Regarding squeeky tachometers in colder weather, Frank Mallory said: I have a theory why this happens: the tach and speedo cables contract and shorten slightly. When they shorten, if they are snug in the instrument head, they pull the rotating drum inside the instrument, against the inside back of the instrument case. There is normally no lubricant there, so this makes it squeel & causes the needle to jump around. The solution is not to lubricate the instrument, which would be hard to do; rather, fix the end of the cable so that it doesn't bind & pull. Dress it down with a file, then lubricate it with CLP or some other kind of low-temperature oil (e.g. gun oil).

Will Samples added: I have had several cars made in the same era as the 113 and all of them suffer from either squealing tach or speedo. All I do is have the instrument serviced. I assume they take it apart and refresh the lube inside. (A squeeky) noise in the speedo is usually inside the speedo, not in the cable. It is especially noisy in cooler temps. The fix is to have the speedo serviced. Also, do not reset the trip meter when the car is moving.

Cees: when my tach started to screech from time to time, I simply replaced the cable. It not only has stopped screeching completely, but also the needle is now rock-steady, where it used to bounce a little bit around certain RPM's. The cable was inexpensive and fairly easy to replace.


'69 white 280 SL

[supergrobi]

hey cees -

i had the same thing happening to my '70 280sl - brutally annoying tach squeaking... i had it serviced for around $100 and it cured all problems. according to the specialists' company that did this tach service, some lubricants inside the tach simply age and dry out over the years. in most cases, serviceing tach/ speedometers is the only way - which by the way you will have to have done by a specialists due to the special chrom ring that surrounf the instruments.

regards from hamburg
jens

[Cees Klumper]

This is going to really raise some hairs - but I was succesful in removing and re-applying the chrome ring on my tachometer. The glass had become extremely foggy on the inside and one day I just could not stand it anymore. It came off surprisingly easy (pried the back loose at some length with a small screwdriver), I cleaned the glass, put the ring back on and, using pliers, carefully closed it again. From the front there is no visible sign anything happened. Obviously from the back there is, but this is hidden. I figured that, if I would botch the job, I could always take it to the experts and have a new ring fitted, which they would do anyway if I took it to them to clean. Now the glass is crystal clear again. Most Pagoda's I see have this fog inside the instrument glasses.

Cees

'69 white 280 SL

[supergrobi]

cees - that's right!

that encourages me to get down on my middle combo instrument that shows some signs of fog, as well. for simple "fog removal", your technique is perfect - and cheap!    for fine-mechanical repairs such as serviceing the tricky intestines of a speedo there probably is no way around "leaving it to the experts..."    

thinking of undoing the combo instrument again keeps me worried - i am afaid of breaking the fine oil pressure gauge. does anyone have a tip for successfully disassembling the middle combo instrument without turning yor interior into an oil field?

regards from hamburg!


-----------------------
"if all else fails, read the f***ing manual"

280SL 1969, steelblue metallic, Euro 4sp shifter, hard/ softtop,
Becker Grand Prix Cassette Full Stereo, rear jump seat, light grey leather, luckily no headrests...

[n/a]

I did this today!
  While reassembling my dash I noticed that the glass on my center cluster was filthy on the inside,so just like Cees, I pried gently with a small screwdriver and Voila! clean glass. I had to do it, it would have drove me CRAZY!!! Reassembled just fine
   Don't be afraid, Be careful.
         Slugger66
        66 230 euro