So like I said I bought two check valves from yall awhile back and when I order them I read the part number off the existing Parker check valves I have on my Hydraulic system and when I got them in there smaller in size there not as long f as the existing ones I have on my system well I was waiting for a new pump head to arrive to test the system out and I blew the new check valves off twice before I went back to the old ones and I'm not sure why that happened this is the first time I've experienced anything like that out of my Hydraulic system with that being said maybe you can shed some light on what I need to do if not I have 2 brand new check valves that are worthless to me!! I can share pictures of my set up if you need me to and you can see how there ran and how I'm using them plus I can show you the difference between the two!! Please get back to me asap so I can figure out what to do with the new ones?? Sincerely Shaun Whyte