Jumping Speedo Needles.

[WGB]

Both my 116's have started out with jumpy speedo needles.

My 450 was particularly bad and could oscillate over about a 40km segment at low speed. I purchased a new cable about 3 years ago for about $75 and the needle on that car now is rock steady.

My 6.9 has had a little flutter of the needle and when I went to order a new cable  9 months ago I was told it was 6.9 specific (which I find hard to believe) and that they wanted in excess of $200 for it (Probably dearer now).

The wobble wasn't that bad so I did nothing and at the last M-B Car Club of WA was talking to somebody who suggested shortening the inner cable.

I did this last weekend and removed about 2 mm of the inner cable at the speedo head end - voila - an almost (but not quite) rock steady needle.

Seems a worthwhile improvement and if I don't like it I can always buy a new cable - as I probably will at some time in the future.

Bill

[koan]

My 6.9 has had a little flutter of the needle and when I went to order a new cable  9 months ago I was told it was 6.9 specific (which I find hard to believe) and that they wanted in excess of $200 for it .

The cable could be different because the 6.9 transmission case is about 50 mm longer than the 450.

koan

[Big_Richard]

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[koan]

Is it the bell housing that makes up the extra length?

I read somewhere the body of the transmission is slightly longer to accommodate extra plates in the clutch packs and wider bands. A quick look at my books mentions the clutches and bands but not the body change.

I looked at the EPC awhile ago about this, the 450 and 6.9 bodies are a different part number but that could be anything.  Maybe need to measure them.

The tailshaft might just be stronger to take the extra torque.

koan

[s class]

Thanks Bill,

Related to that- I know you have played with speedos - how does one remove the needle (in order to remove the face plate) without damaging anything.  Similarly, I need to remove the needles from a combination guage. 

[koan]

I'd like to know the secret too.

Managed to wreck one needle getting at the face for painting.

koan

[WGB]

Thanks Bill,

Related to that- I know you have played with speedos - how does one remove the needle (in order to remove the face plate) without damaging anything.  Similarly, I need to remove the needles from a combination guage. 

I have pulled my needles off using my thumb and middle finger nails. My nails are strong and I usually let them grow a week or two longer than normal before I pull off hands. (I also fiddle with old clocks and it's all the same principle).

The problem with the speedo needle is that there is a separate "hub cap" over the centre of the needle which will pull off if you go over a certain amount of force but it should be easy enough to use a dab of glue or whatever to stick it back down - it is only decorative.

Failing that I have a "Chip puller" made from stainless steel which I purchased for working on my first computer (An Apple 11) in 1982 which is like a pair of tweezers but with right angled slim tips that fit under the centre of the needle.

They all come off with a strong enough pull (as the Actress said to the Bishop) and I've never been beaten yet, nor have I ever done terminal damage to any needle or clock hand - just be careful to get adequate grip and pull exactly vertical to the line of the shaft.

The problem begins when you put it back on as it is this initial position which calibrates the instrument.

I know with my 450 speedo that I removed it about 5 times and re-positioned it until I was happy with the calibration.

Unless you put the needle back on with excess force the initial removal is always the hardest as in all likelihood the needle has been affixed there for 30 years.

Bill

[TJ 450]

I have read this thread with great interest, as I will have to correct this problem on both my 116s at some point in the future.

Tim

[s class]

The shaft that passes through the face-  does that come out with the needle, or does it remain affixed to the guts behind?

[koan]

The problem begins when you put it back on as it is this initial position which calibrates the instrument.

Around the outside edge of the speedo face are a several small white markings that are normally not seen when the speedo is mounted in the cluster.

One of them is just anti-clockwise of the 0 kmh stop pin. I was told years ago that this shows the rest position of the needle when the speedo is held at its installed orientation. Gently lift the needle over the stop pin and it should point to the mark.

On the speedos I have here it does seem to be correct give or take a few degrees.

Before removing the needle ease it over the pin and check its rest position. If it points to the mark all is well, if not make a small pencil mark. The needle can be re-installed in the same position and eased back over the stop pin.

The speedo must be held at the installed angle for this to work.

koan

[WGB]

The shaft that passes through the face-  does that come out with the needle, or does it remain affixed to the guts behind?

The shaft stays where it is and the needle is a press fit over it Ryan.

The problem begins when you put it back on as it is this initial position which calibrates the instrument.

Around the outside edge of the speedo face are a several small white markings that are normally not seen when the speedo is mounted in the cluster.

One of them is just anti-clockwise of the 0 kmh stop pin. I was told years ago that this shows the rest position of the needle when the speedo is held at its installed orientation. Gently lift the needle over the stop pin and it should point to the mark.

Didn't know that - thanks for that info.

Bill