Replaced the worn out pump head on my Zefal floor pump. I chose the Lezyne dual pump head because I have had great success with thier other products. My problem is that the Presta side of the head does not slide down far enough to engage the valve stem. I can still pump up the tire by just over pressurizing the valve but the gauge on the Zefal floor pump will not show the tire pressure but rather the residual pressure in the pump hose. I am now just pumping up the tire to a ball park figure then checking the pressure with a Presta Tire pressure gauge.

Is this going to be a regular method or will the head loosen up to the point the presta valve gets depressed allowing for a better reading on the floor pump gauge? Or is there something I am missing in its application?



SOLVED: As suggested I applied some silicone grease to a Presta Stem and the inner O ring. I still had the problem and could not get the stem down into the head far enough to actuate the valve. I then took a round wooden skewer just large enough to fit into the head and closed the head with the lever around it . At removal and examination hole in the head was now larger. The head now slides onto the Presta stems normally. I suspect that the O ring in the head was not seated properly and after closing around the skewer it is now in place where needed.