Everyone on here says to pump the primer a few extra times AFTER closing the bleeder screw (until it gets firm) and I do the same thing. I've noticed though that after I drive it for a while, if I check it again, it's gone "soft" and I can almost always get a pump or two out of it before it gets firm again. Truck runs fine... no symptoms of air in the system or anything. Is this normal or is my primer pump defective/going bad? Do these things ever fail? (I'd hate to find out when I really needed it)

Thanks in advance,
Eric