Hot water crossing over into cold on 2 handle 2011 Pfister kitchen faucet, it has no diverter

[qkcam]

I have a 2011 Model LF 035-3THS pfister. Hot water is crossing over into the cold side. I tried changes cartridges and also changed the little seat springs and screws. I still have cross over.

I got curious a while back and took it apart to try and understand why the water is crossing over. the only thing I found inside are 2 little o'rings that attach to each side of the little piplet thing (sorry I dont know the name)..

since the new cartridges didn't help , could it be I needed pfister specific rather than generic from hardware store? could it be the little o'rings that are on the "piplets" that are on both sides?

its the old cartridges in the photos

is it just time for a new faucet? It would be great to learn and understand why this is happening.
I realize the best option considering the age is to replace.. yet still curious since there isn't a diverter and replacing the cartridges didnt work.. what else could it ? Unless the generic ace hardware cartridges for some reason aren't the right fit, although they fit. ?
I noticed those little black O'rings look pretty spent. not sure if that would cause crossflow. it was pretty fun to take apart.

thank you

 

[qkcam]

sorry i dont know how to delete this reply