[urq] URQ Speedo

[urq]

The speedometers on most cars back in those days are loosely magnetically
coupled to the spinning of the speedo cable with a return spring that pushes
the needle back toward -0- (opposing the magnetic drive).  What I believe is
happening is that while the car sits the speedo shaft is forced against the
stop by the return spring and gets jammed into a position which the
magnetically coupled drive cannot overcome right away.  After the car begins
operating the magnetic drive, perhaps with the aid of the normal
shaking/vibration that goes with a moving car that knocks the needle loose.
There may be some sort of corrosion going on in the guts of your speedos and
that is why you have two that behave similarly.  

If I were in your shoes I'd open up the IC and remove the speedo mechanism.
I'd look to find the stop mechanism and see if I could determine why it is
sticking.  I suspect that a minor adjustment of the stop will repair your
speedo.  You can try pushing the speedo needle into the stop to make it
stick and then feel for the stickiness as you try to move the needle in the
positive direction.  This technique might help you find what is sticking.
The other thing I'm thinking is that whatever bearings the needle rides are
sticking.  If it is a jewel bearing it may be that it needs to be adjusted.


Steve Buchholz

-----Original Message-----
From: dgraber460
Sent: Wednesday, August 17, 2011 5:19 PM
Subject: [urq] URQ Speedo


 I have been having an issue with my speedometer (I have 2 and they both do
it), in that it will keep clicking off miles on the odometer (so I know the
cable is intact and spinning) but the needle wont register speed. Stays on
the peg, and then out of the blue will spring to life and work for the rest
of the trip. When it started, I took it to Denver Speedometer, a place I had
used in the past, and the guy just sort of blew me off and summarily said
"$300 to rebuild it", and then asked to see it. He took a small screwdriver,
stuck it in the back and turned it. The needle bounced and he handed back to
me said "its fine, there's nothing wrong with it". He said the needle is run
by a magnetic pick up, and not a possible electrical impulse or any other
"usual" suspect. The problem seems worse when its hot.
Any ideas or solutions?

 

Dennis 
Denver

_______________________________________________