Ryan---What your speedo repair shop said about the "long" square drive
has also been said by others who should know. West Valley Instruments,
for another, recommends that the square drive be no longer that 1/4
inch where it protrudes in the speedo. Interestingly, every replacement
cable I've seen has this measurement between 3/8 and 7/16 inches.
When the cable internals are the reason for the bouncing, it is usually
because of a momentary 'windup' inside the cable sheath. When the
tension releases, it can make the speedo needle bounce. Lack of
lubrication, too tight of a corner, or a worn sheath are the usual
suspects. Since you have a complete new set, look for a sharp corner for
the cable to turn. Reduce the square drive to the recommended length if
there's nothing else found, if ony to put this idea to rest.
I keep a short length of speedo cable handy to test speedos on the
bench. . A drill motor supplies the turning.
Dick
Ryan wrote: guys,
i had a bouncing speedo needle, tended to get worse the higher the
speed. i replaced it with a grey repro one from TRF, and it's still
bouncing. so i took the speedo out and brought it down to palo alto
speedo. he tested it and it wasn't bouncing. the only things he could
think of that could be causing the bouncing would be from a bad angle
drive (which is not present on my car), or that the square cable input
shaft is a little too long - so that when the attachment nut is
tightened to the speedo, it causes the input shaft to push too hard on
the internals. i haven't had a check that out yet, probably not until
this weekend. anything else i should try if that doesn't seem to be the
problem?
ryan
'71 imperial blue (sapphire)
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