I have a Topeak MMB 2 Mini Master Blaster that does not seem to work right. It will pump a little air but not well. When pulling it open (intake stroke) there is quite a bit of resistance like it can not breath in. It only seems to "inhale" for the first two inches of the stroke and not for the remaining 4 inches. I pulled it apart and did not find anything obviously wrong. The Topeak support web site mentions a "check valve" but I do not see anything that looks like a check valve. Any suggestions?

The check valve is a one-way valve that lets the pump "inhale" outside air but closes so the pump must force that air into the tube and prevents the air in the tube from flowing back into the pump. It is normally a small metal ball (looks like a ball bearing) located near where the hose connects to the pump base.

This pump does not have a hose. It is the small type that mounts on the bike frame and has a "grabber head" that connects to the schrader valve. The head looks pinned together. Should I try to press out the pins? Thanks