Best bet is to replace the cable entirely. The cables are exact length, which will require you to route through the original locations as there is no extra slack. Replacing my cable cured the bouncy speedo on the 4.5.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.