SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I've cleaned up some of them, and they do work beautifully.
Zone One has 4 pop ups.
All four pop ups leak, they are brass. The local hardware store only had 3 of the 1/2" female 90 degree threaded connectors which these older kind use to attach to the PVC pipe.
Guess my question is : do these older Brass rainbird half circle pop-ups outperform the newer plastic type? Am I missing some rubber gaskets on these, causing them to leak and sputter?
These appear to be only 35-50% of performance.
This repair project is going to be time consuming, since its not my
main occupation, and as a Do-It-Yourself my efforts so far have been successful. All 9 zones discovered, installed the control and lines.
Zone 2 is okay, but has some still "low" pop-ups, and 1 or 2 "leakers"
Zone 3 is better but configured only for misting - all with brass rainbird sprinklers with small nozzles.
Zone 4 : installed a large sprinkler *new from store*
to replace a defective brass one which I guess lost the cover and so forth... Have not activated beyond zone 5, since another Leak burst open today. Geez, this is work!