I have "finished" my truck, just making some adjustments and little
additions. One of those adjustments is the speedometer...
If I go take the truck out right now and go down the road at 45, the
speedometer will read 50. No big deal, I can live with that.
If I drive for about 10 to 15 minutes, and I'm still doing 45, it will
read about 40.
A few more minutes and it will read 35... if I'm out for 20 minutes or so,
it will start to bounce between 25 and 30, or just hover somewhere between
If I'm driving for 45 minutes or more, it will just read 0 while the truck
is still doing about 45 down the road.
Now, if I let off the gas, it will immediately pop up to 50, then go down
as the truck slows down. If I push in the clutch, it will go back down,
sometimes between 15 and 20, and just sit there until I am almost stopped,
then go down all the way. This is very well defined and happens every
time, there does seem to be some direct connection.
At first I thought maybe the pedals were hitting on the speedometer cable,
so I tried moving it around to various different places, clipping it to
things, etc. Nothing helps.
I pulled the cable out and looked at it, it's lubed good, pulls out and
turns very easily, and fits snug into the back of the speedometer. There
doesn't seem to be any frey on it. It *has* been replaced, it's not the
original cable. Seems to be long enough, though.
I tried unhooking the cable and just letting it hang while I drive down
the road with somebody to watch the cable. It doesn't seem to pull in or
push out or anything.
I tried another speedometer and it does exactly the same thing, but this
doesn't sound like the speedometer itself. Nor does the cable seem to be
such an obvious thing, since it reads 0 after a while. If the gear is
turning, the cable has to be turning, it would seem. Unless something on
the cable gets hot and prevents it from turning properly. I know the end
that goes into the speedometer is plastic. That makes me wonder...
By the way, there don't seem to be any noises involved. No grinding,
I'm not sure what else to do or what it can be. Anybody have any ideas?
By the way, if you want to see the truck, I have a picture up:
1950 Chevy 3100
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