RE: STOP! Re: odometer not odometering either

[Matthew Caprio <cap29100@flash.net>]

Well, there are TWO failure mode as I have already explained.. One does NOT
require faceplate removal, and one DOES.  The latter mode is where the
metal end gear (not the worm set-- this is the one inside the mechanism)
begins to slip on the main lay shaft.  The only way to repair this one is
to remove the assembly and peen the main gear and/or spline the shaft for a
tighter interference fit.  This, when done properly, will not fail again.

With regard to the calibration-- the rest position is not the only factor
involved in the speedometer adjustment..  Over time the preload spring
usually weakens, and thus the speedo is wrong when you take it apart-- even
if you put it back in the same place, it would still be wrong.  SO, the
repair of the gear problem is also an opportune time to calibrate it as
well.  This is done by inputing a known rpm into the speedo, and reading
the speed.  Each model has a different ratio, so you have know the specs of
the one you're working on in order to calibrate.  You also have to have a
very accurate speed source (like a synchronous motor).  This, is how the
professionals do it.

Therefore, I STILL recommend that you don't repair these yourselves.  And,
I wouldn't take it somewhere where they fix it and it brakes again... I
wouldn't call that a "great job". 

IMHO,BTDT,TIA,HTH,M2CW,MTC,AWEPS,BLAHBLAHBLAH

Matt

At 11:57 AM 11/15/99 -0800, you wrote:
>... IME, you can repair the odo without even removing the faceplate at all.
>This would be on the ur-q/older 4k, so YMMV.  In any event you will very
>likely find that if you allow the speedo needle to pass the stop pin it will
>rest at a location where there is a line in the silkscreen of the speedo
>face.  How do you think that the "professionals" do it?  If you can't seem
>to find a mark on your speedo face you can put a piece of masking tape on
>there and mark it for yourself.  Just reinstall the needle in the same
>position and you'll be good to go.  
>
>For those who are feint at heart and live in the San Francisco Bay area
>there os another place to have the work done called Palo Alto Speedometer.
>I took the speedo from the ur-q there the first time it failed and they did
>a great job.  Once it failed again I figured that $65+ was a bit too much to
>pay for a temporary fix.  
>
>HTH!
>Steve Buchholz
>San Jose, CA (USA)
>
>> -----Original Message-----
>> WAIT!
>> 
>> Of course this can be done, but DON'T DO IT!  There is a rotary spring
>> preload on the needle that keeps it resting against the stop 
>> pin.  If you
>> take the needle off to fix the shaft, then, you have no idea how much
>> preload to put on the shaft when you put the needle back on.  
>> So, the end
>> result is that your odometer works, but your speedo has a significant
>> error.  I have done this before, and it is no fun.  There are ways of
>> trying to calibrate this yourself, but I assure you it's just 
>> not worth it...
>> 
>> Leave it to the professionals.
>> 
>> I used "Overseas Speedometer" in austin, tx.  
>> www.speedometer.com  Cost is
>> about $65, but it is totally worth the two hours you would 
>> spend monkeying
>> with it, only to scratch the face plate, end up with your 
>> speedo being 17.5
>> mph off, and then, have your odo repair fail again after 
>> about 2 weeks.
>> (this has happened to me, and I'm pretty good at instrument repair).
>> 
>> Matthew Caprio
>> 
>> 
>> >Does anyone know how to remove the needle (so I can take 
>> >the face plate off) w/o rendering the spedo usless?  I looked in the 
>> 
>
>