speedometer.

Hi Guys Happy new year to all, not a good start I know! But can anyone help? I recently helped to change the swvel housings, brake discs etc on my mates 1988 range rover and now the speedo has gone crazy and the needle has permanently gone around the clock clockwise, then when you turn on the ignition it moves a further centimetre until it is resting on the pin, I have check the sender near the transfer box and that has power but I was wondering if the abs sensors have anything to do with the speedo as that is the only relevant part we have disturbed that I can think of, thanks in anticipation Nigel.