How do I use this bicycle pump?
 

Here is the pump: Imgur: The most awesome images on the Internet

Which way does the gray switch go? Down or Up? I tried it with a presta valve and it seems both ways leak air no matter what I do.

Are you opening the valve to inflate it? Have a look .

You could take the Pump head apart and see what the lever does?

that is what I would do without the internet , see what the mechanism does ..

I'd Guess Up is gripping so its releasing as you push the lever down ..

+1, open the PV lock Nut and burp the check valve.





'/,

Turn the head so you're looking straight into the hole. The lever will make it larger or smaller. I assume you can take it from there.

Start with the grey lever down. place it over the stem then lock it into place by lifting the lever up.

Only makes sense because the lever has to be down while being transported on the bike holder.

Looking at the image, it seems there may be two holes at the underside. One for presta and one for schrader. Are you sure you are using the correct hole?

We had the wheel out. and stem at 12:00 , and sort of hung the wheel by the stem from the Pump

This was frame fit pumps with Campag Pump heads , 1 hand gripping the pump with a thumb over the tire..
he other pushing the Plunger ..




:50:

Tried the pump again on an empty tube, when i pump the presta valve, some air leaks out of the shrader valve. the tube still fills with air though, but i can't imagine getting a high psi or volume if some air keeps coming out during pumping.

is this normal for these kinds of mini pumps?

The pump employs a slide valve that rides the air flow to the open port and closes it. Sometimes it can be sticky, and it's less effective at lower pressures. But once there's some resistance form the tube, the increased pressure closes the slide valve completely

If yours isn't working right, either it's a bit sticky and needs to be worked a bit, or you simply don't have enough back pressure to close it completely. You might test the valve by trying to pump against a screw or other plug of the PV port.

Well, I tried it on a shrader valve, this time the tire was on the wheel, and the pump does work. I didn't pump up the tire all the way, it was taking way too many pumps and i felt I was going to break the valve eventually if i kept it up. I was using one of the spokes and my hand to brace the pump but it was still unpleasant to pump up the tire