Toro sprinklerhead not retracting.

[ls3c6]

I have several 570Z PRX spray heads and 800 SUPER rotors that fail to retract after a cycle, i've kicked them, wiped them, disassembled them, swore at them... should I lube with WD40 as i've seen on the web or will that make it worse? Really not interested in replacing all of them.

 

[CountryBumkin]

The internal spring is what causes the popup head to retract when the water pressure goes to zero. Have you checked the springs to be sure they are not broken?