On cars equipped with a trip odometer, the speedometer and trip
odometer are prone to jerky operation. That is, the speedometer
will bounce wildly and the trip odometer will not roll over evenly.
This is not only annoying, but will prevent use of cruise control if
the car is so equipped.
Before you disassemble the entire speedo cluster and/or crawl under
the car to pull a presumably kinked cable, check the trip odometer
reset cable. It can bind in its housing, which will prevent the
pawl on the end from completely retracting from the odometer
mechanism. You may be able free it by simply pulling down on the knob
under the dash. For a more permanent solution, look under the
dash to see how the cable is routed. There is a hole in one of
the dash support brackets (behind the dash) immediately above the
reset knob mounting hole. If the cable is run through this hole,
it is a much straighter run from the odometer to the knob, and less of
a chance that the cable will bind. Many of these cables are
routed behind this dash bracket, which results in two very sharp bends
in the cable.
If you need a new rubber knob for the end of cable, you can get one
from Buick Specialists ((253) 842-0584, part # RK-465, $2.95) or
Clark's Corvair (www.clarkscorvair.com,
part # C19, $3.45).