shower diverter valve is now hard to activate
 

. . . after I replaced the showerhead with a showerholder with a metal hose
and a handshower. I have one of those Delta tub faucets with a diverter
actuator handle at the end of the tap: pull it up for the shower - down for
the tub. With water at full pressure, it is now much harder (but still
possible) to pull the handle up for the shower. I also need to apply more
pressure to force it back into the tub position. With water at half the
pressure - no problem. I suspect because of my shower installation, it is
harder to force the water to shift from the tub to the shower position, but
I do not understand why.

I removed small o-ring mesh filter, check valve, and flow restricter from
the shower unit. I think it got a bit better but not by much. I still need
to see what happens if I disconnect the metal hose form the showerholder
base - it is a bit tricky and I am not up to this challenge at the moment.

I would appreciate an advice.

Thanks.

Dmitri