speedo issue

dan.2cv · Post by **dan.2cv** » 10 Mar 2005, 00:29

hi guys, this is for a speedo on an old Golf, but I'm sure most cars are the same:
The speedo was suddenly stuck at 20mph with the car stationary and wasn't moving. I disconnected the cable at the box, squirted some wd40 down it and worked it in. Connected to a drill, the speedo winds up to 40MPH (probably the 'speed' of the drill) and just stays there. putting the drill in reverse makes it go back to 0 MPH. It won't go back unless I reverse the drill.
So is it the cable or the clock?
I've got the day off tomorrow and getting the clock out isn't hard, but im sure it will be near impossible to test the clock without a cable attached.
I thought the speedo rested at 0 MPH and only wound up due to spinning magnets. When the magnets stopped it just returned to rest, meaning the clock is Donald. Am I wrong?

jeremy · Post by **jeremy** » 10 Mar 2005, 01:27

Its the clock - after all if it is functioning perfectly the needle goes to zero whenever the cable stops moving - its not dependant on cable position.
With the clock off you only need to jam a screwdriver or something similar into the squared socket to enable it to be rotated to test it. The pointer should move smoothly and drop to zero on its own when rotation stops. same with drill - don't go too fast!
jeremy

NiSk · Post by **NiSk** » 10 Mar 2005, 17:21

Sounds like the return spring has become dislodged inside the speedo (or its just plain sticky).
//NiSk

dan.2cv · Post by **dan.2cv** » 14 Mar 2005, 17:15

Well guys it turns out to be the cable. On the bench, clock and cable connected it all works fine. Clocks work fine on their own. Back on the car it all goes sticky again. The cable has chaffed through at a grommet and gone nice and rusty and swollen, and I think routing the cable throught the engine bay puts a strain on the weak bit.
At £27 from VW I can't be arsed.
ps,the top speed of my battery drill is 43 MPH!!