I've come to realize that pumps are a consumable item. They go out of production after a while and and you can't get parts.
I spent $60 on a Silca pump a few years back. I bought it because I thought it would be the last one I'd ever buy and would simply replace parts as they wore out. The first one was defective. Money wasted on postaqe back and forth. The second one lasted about a year and then would only pump small amounts of air at the end of a stroke. I took it apart and for the life of me couldn't get it to work. It went in the trash after I bent it in half and drove the car over it.
Get $20 pumps on sale and plan on getting a few years out of them. It's all crap made in China.