Trip odometer/Speedometer issue

[Jamiez]

I did a quick search but didn't find anything right on point (and a search for speedometer returns a lot of results). The 150mph speedometer/Odometer in my 1974 has the following issues:

1) The speedometer needle "wiggles" up and down over a 5-10 mph range. At higher speeds this seems to stabilize 
2) The speedometer seems to read a little high.  When the car is going around 60 it reads between 65-70. 
3) The trip odometer does not seem to read at all.  It did have miles on it but ever since I've reset it he's been sitting at 0.  The regular odometer appears to work fine

The posts I read about similar issues mentioned things like stripped gears, the wrong size gear and the speedometer cable.  I'm really just looking for a good place to start

[CHL2T]

Lubricate the speedo, odo and trip meter.  Get the proper size speedo pinion....... 

[Grec]

For MPH accuracy... yeah. Verify that you have the right speedo gear. If it's wrong for the diameter tires you're running in the rear, it will be off.

Make sure the speedo cable is lubricated inside as mentioned and in good condition.

As to trip odometer... try pulling out / pushing in the reset knob. I always have to do that when I reset mine to get it to re-engage and start rolling over again. If I just push it in to reset, it doesn't re-engage. Might be as simple as that.

[cwestra]

Does anyone know what the proper lubrication is for the speedo cable?

[Chryco Psycho]

the best is silicone Grease , not available when the cars were built but it will not harden over time like white lithium can

[cwestra]

the best is silicone Grease , not available when the cars were built but it will not harden over time like white lithium can

Great.  Thanks.

[mopar jack]

Red line gauge recommends to clean cable with wd 40 and lube with wheel bearing grease.

[burdar]

When you said the needle bounces, the first thing I thought of was a dry/dirty speedo cable.  However, when you said the trip odometer wasn't working and the speedo is reading high, that tells me the speedo head needs to be rebuilt.  Time to send the speedo out for a rebuild.

[Jamiez]

This thread came back from the grave.

My speedo problems were two fold:

1) Burnt/melted cable.  This caused all the wiggle.  The wiggle was so erratic that the trip odometer was working, but so inaccurately it was hard to tell
2) Wrong sized speedo gear.  Big rear tires and the stock gear.  It was off by 2 or 3 sizes.

Now that that is fixed everything is working normally.  The speedo is a still a bit high but the next size down makes it read too slow.  Just have to pick one or other other.  I like to pretend I'm going fast