Another speedo thread! I did the odometer fix but now the speedometer needle bounces like crazy till I get up around 35 MPH then is fine. I had removed the screws on the face (dont ask why) and am wondering if the face rotated 360 degrees in my frustration and relieved some of the "spring load" on the needle. Any thoughts.
Speedometer, not odometer issue
- Thread starter bavbob
- Start date
Honolulu
Well-Known Member
I don't recall the face has any effect on the needle.
A jumping needle suggests that the wire driving the speedo is hanging up in the housing somewhere. I'm sure you don't want to remove the speedo (again) so.... review the install to ensure that it is correctly done and not binding.
A jumping needle suggests that the wire driving the speedo is hanging up in the housing somewhere. I'm sure you don't want to remove the speedo (again) so.... review the install to ensure that it is correctly done and not binding.
The needle has some spring loading (if it is on your bench top and you manually rotate it, it comes back to zero) and rests on the stop pin at 0mph. If you undo the face, if the face rotates counterclockwise a full 360, the needle may rotate with it and affect the spring loading. That's my logical thought since it bounces till 30 MPH upon which I think the needle clockwise rotation is enough to put it back under some tension and stop the bounce. Make any sense?
Before you remove the face ( which you have to do to repair the odometer)
you carefully lift the speed needle over the stop pin at the bottom.
The needle will naturally come to rest over a scale under it's point. Reference that spot so when you put the needle back and lift it back over the stop pin you will hopefully be close to the right position for accurate speed reading. The face has no effect on the speedo or the spring.
As far as jumping goes it is usually the cable. You can disconnected the cable at the trans and hook a drill to it and observe it turning behind the instruments, that is if you took them out.
Mine was erratic but not jumping. My cable was ok. It is now at Hollywood Speedometer to get recalibrated.
you carefully lift the speed needle over the stop pin at the bottom.
The needle will naturally come to rest over a scale under it's point. Reference that spot so when you put the needle back and lift it back over the stop pin you will hopefully be close to the right position for accurate speed reading. The face has no effect on the speedo or the spring.
As far as jumping goes it is usually the cable. You can disconnected the cable at the trans and hook a drill to it and observe it turning behind the instruments, that is if you took them out.
Mine was erratic but not jumping. My cable was ok. It is now at Hollywood Speedometer to get recalibrated.
I have another speedo with a non-functional odometer and the needle is rock steady so the problem is the speedo.
The face does not effect it but the pin on the face holds the need at 0mph. if you remove the pin and the needle is under spring tension, it my rotate freely and if it does this for 360 degrees, when you put the face back and set the needle back in front of the pin and fail to rotate it back, the tension is less. I am going to rotate the needle one revolution and see what I get.
I have surgical tools, in particular a small "Kelly clamp". if you remove the screws on the face, you can pivot the face , use the Kelly and remove the screws holding the speed together. No need to remove the needle.
The face does not effect it but the pin on the face holds the need at 0mph. if you remove the pin and the needle is under spring tension, it my rotate freely and if it does this for 360 degrees, when you put the face back and set the needle back in front of the pin and fail to rotate it back, the tension is less. I am going to rotate the needle one revolution and see what I get.
I have surgical tools, in particular a small "Kelly clamp". if you remove the screws on the face, you can pivot the face , use the Kelly and remove the screws holding the speed together. No need to remove the needle.
Face removal
My question is, how do you remove the speedometer lens? The chrome ring that holds the lens on appears to be crimped in place.
My question is, how do you remove the speedometer lens? The chrome ring that holds the lens on appears to be crimped in place.
Sorry, to clarify, I have an E3 so a cluster rather than seperate components. No ring to deal with.
restart
Well-Known Member
So here is the answer. The speedo needle is spring loaded and the spring is calibrated to the RPM's of the speedo cable to accurate reflect the MPH. With the speedometer/needle at zero, if the spring is even slightly to tight, the needle does not move till you are at 10-15mph and underestimates your speed. If too loose, it accurate reflects your speed but bounces (like mine did) till you reach enough speed so the spring has enough tension to dissipate the bounce. Bottom line,when working on a speedometer, ensure the needle stays fixed so the spring tension is not altered.