4 replies to this topic

[the.stroker]

sicnce shifty and i replaced the dash the speedometer no longer works and is permanantly stuck on 18 mph,the cable is firmly in place however after looking at the gauge itself its lost its spring as if you turn it to max it will only return to 18.mph,the needle was replaced in the same location upon re - assembly
anyone got any idea,am i looking at a new gauge??

Edited by the.stroker, 20 January 2009 - 08:51 PM.

[the.stroker]

bumpety,bump

[Shifty]

Can't you just remount the needle so it reads zero?

[the.stroker]

could do mate but nothing is ever simple with my cooper,think im gonna have to take it out again and have a proper look,fun and games pulling the dash to bits lol

[dklawson]

You will not like this answer because it is not simple to do.

Ideally, remove the speedo from the car and open it up again. Remove the needle. Hook a broken piece of speedo cable to a variable speed DC motor and drive it at the RPM corresponding to the TMP (turns per mile) number that should appear somewhere on the gauge. Running the DC motor at this speed it will correspond to the speedo reading 60 MPH. Put the needle on while the motor is running, position the needle so it's pointing at 60 MPH. Again, this requires you to have a nice variable speed DC motor and a drive to control it. I use a small table top lathe for this.

OK, so you don't have a table top lathe? Get a friend with a known good speedo OR use a GPS that can give you an accurate indication of your driving speed. Drive at exactly 60 MPH (as indicated by your friend's speedometer or the GPS) and note exactly where your speedo needle points. Return home, remove the spedo and open it up. With the speedo opened up you should have access to the aluminum drag cup that is attached to the spindle that the needle is on. Turn the drag cup by hand until the needle points at the exact position you noticed while driving at 60 MPH. Now hold the drag cup securely so it won't move. Pull the needle off and place it back on pointing to 60 MPH.

If one of these methods does not fix your problem, take the speedo into a repair shop for proper re-calibration.

That looks like one of the Japanese speedos so I can't offer more specific information. On Smiths speedos and tachs I make it a point to place a permanent ink mark on the drag cup and speedo frame so I can reposition the needle correctly when I need to remove and replace it.