Skip to main content

Reply to "odometer needle"

Think of your speedo drive cable as a very long flexible screw thread. Over the years rubbing on the the middle layer of plastic, things wear. The inner cable is spring steel so it tends wears the liner & outer steel jacket at the center of bends where the pressure is highest. Nice, attractive, tight bends wear fastest. Once the plastic low-friction liner is worn thru, the drive cable can catch worn edges of the liner or steel jacket and cause the needle to jerk. Eventually, it breaks. This is why replacing only the broken inner cable usually results in quickly breaking the new one.

New cable assemblies are built with better materials than 45+ yrs ago and come in two lengths depending on what's in your car now. Remember, unless you are an original owner, you have no idea what's been kludged together by POs. Lubing a worn cable is a very temporary fix at best- if it does anything besides make a mess.

The way your right-angle drive ass'y is attached to the ZF influences smoothness as well. The left/right-threaded nut on the assembly should be adjusted ALL THE WAY UP, so when applied to the threaded adapter sleeve, the drive tongue inside is all the way DOWN into the visible forked end of the ZF drive gear. On some cars, you will have to play around with the position of the right-angle assembly to get the drive fork down far enough. This alone smooths out speedo action and extends the life of the whole drive unit. The tightness of the big left/right nut has no effect on leaks- those come from a broken o-ring inside the drive assembly. Pliers-tight is good enough.

When I fix broken right angle units (up to about 50 now), I add a zerk fitting so the poor thing can be lubed occasionally. It was not designed for service but with difficulty, it can be modified. Mangusta right angle drives are built differently and wear the gears & thrust surfaces (which are irreplaceable so far), rather than breaking the fork-&-tongue drives. A Pantera assembly of the proper cable thread size can be substituted. New OEMs are no longer available as far as I know.
×
×
×
×