[byrd]

Repop or oem gauge? If oem take out the three 1/4" screw that hold the vac and oil pressure gauge in the dash and remove the two gauges from the dash. Then get some PB blaster(penetrating oil) or similiar product and spray a small amount on the internals of the vac gauge( Do not get it on the face of the gauge) after spraying working the inners GENTLY a little by hand to get the PB all in where is should be and let it set for a while or till the next day. Then spray or apply a small amount of Lithium grease to the inners of the gauge and put it back in and see what it does, if it works which I'm about 90% sure it will then you are out nada,but if it doesn't work then you tried, and you are still out nothing. Most of the gauges I see and that has been a truckload have some rust issuses with the inner mechanicals of the gauge itself and this info has worked sucessfully for me numersous times and most likely will work for you too. Good luck and let us know how it turns out..Randy