Ameda Purely Yours?

klm42404

I have this pump and really like it, but the past few pumps I've noticed that the silicone diaphragm is not totally expanding after I have been using it for a few minutes. I have to keep taking the white top off. I called Ameda today and she wanted me to switch the parts out one at a time. The only common factor is the pump itself. I've tried new tubing, different size flanges, etc. I can't call back til tomorrow. Has anyone ever had this problem??