If a little grease is good, more grease is better- right? Well it ain’t necessarily so!
The owner of a MGB decided to lubricate his new speedo cable, something which isn’t really necessary but after a period of time he noticed that the speedo needle would slowly move to the proper speed but would not return to zero when the car stopped.
Finally the speedo was removed from the car where on examination it could be seen that the rotation of the cable had forced the grease through the drive gears and into the magnetic cup. This completely fouled the unit.
It took quite a bit of cleaning with a spirit degreaser to remove all the grease plus removing the inner drive cable to try to remove the excessive grease, after which the speedo was soon returned to normal working.
A new speedo cable should not require any additional grease however if you do decide to add grease a little bit will not hurt – but please not to much! Also remember that a cable driven speedo rarely fails and if the needle is wavering to any degree it is almost always that you will find the inner cable dry, the cable possibly kinked, the outer casing has been crushed somewhere or it is making too tight a curve.