Speedo bounces When Coasting under 20 mph

[erickmarciano]

speedo bouncing when I am coasting under 20 mph what can this be?
thanks

1971 280sl
1962 VW
1954 Allstate vespa
1958 gs150 vespa
1962 gs160 vespa

[JimVillers]

Replace your speedometer cable.  "Bouncing speed" is almost always a cable problem.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[Malc]

Suggest before you replace it you try/check the following

Make sure all the connections ie to the gearbox and the back of the speedo are tight.

There are no kinks or very tight curves in the cable.

Sometimes you can extract the centre core, clean it up and add alittle fresh grease (Graphite) which helps it run alot smoother. If it's old it could of "dried" out.

Worth a try
Malc

[Richard Madison]

Can find more info here by a seach of "speedometer" or "speedo" including the joys of replacing the cable...

The three basic solutions I have read about:

Remove the cable and drop oil down the inside of the cable. I never tried this.

Replace the cable. Step by step instructions are in one of the messages in this forum. A replacement cable is about $25. An original cable from MB is about $60. I compared both and went for the MB cable.

Last option: remove the speedo and have it rebuilt (about $100) and also replace the cable.

My speedo was not only bouncing but was also screaming. I had the speedo rebuilt and relaced the cable. It cured the problem.

Once you are in the dash area for the speedo, might want to check out the tach cable, clean instrument glasses, etc. Info about this is on this forum. Use the search with various words.

Richard M