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MG MGB Technical - speedo problems

Hi Folks, my speedo is not at steady speed, when driving it will search between aprox speed I'm going, eg: 30-50 0r 40-60 would you think it's the cable or the insrument?

Cheers Jack

ps: is the cable easy to replace?
Jack New Forest

There's a good chance that is your cable and removing it is fairly simple. You can disconnect it, at the rear or the transmission, and pull out the inner core that drives the speedometer. Clean and lightly lubricate it, with white grease, before re-installing it. Take your car out for a test drive and see if there is any improvement. If not, the speedometer itself will probably require servicing, unless the cable is in extremely poor condition. RAY
rjm RAY

I had the same problem. Cable clean and lube didn't fix it. Removed, dismantled, carefully, the speedo and cleaned and lubed all bearings and problem went away.
Herb
Herb Adler

Does the speed of the "flicker" depend on the speed you are travelling? Once with mine, it flicked each time the "tenth" wheel on the odometer moved - 4 or 5 times per tenth of a mile (I think).
Geoff Ev

Just an idle thought, are modern speedos all electronic? Mike
J.M. Doust

Sometimes they get dry, but usually it's the outer that's worn. If you clean and lubricate, just wipe off the lubricant from the 6" at the clock end, otherwise it can finish up clogging the internals and making matters worse.
Allan Reeling

Ditto Geoff. If it flicks with each movement of the odometer it is the speedo. If it flicks much faster than that it is the cable. Mine was the speedo, and a drop of light oil on the end of the input shaft cured it in my case.
PaulH Solihull

Mike, just about every car being produced today has an electronic speedometer. Keeping all the computer's input signals electronic simplifies things and takes a mechanical fault out of the equation when troubleshooting. RAY
rjm RAY

This thread was discussed between 31/01/2012 and 02/02/2012

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