Need to replace the solenoid but home depot doesn’t have one with a long enough thread. Any help to find one that works?
old one in pictures.
Have you tried replacement Orbit solenoid?
https://www.homedepot.com/p/100013771
Thread length is not as important, the active part is the spring loaded plunger. As such solenoid can adjust to a wide variety of valves, with threads being there just to hold it in place.
It made a difference because I couldn’t get a seal.
Looks like your old solenoid is attached to some sort of adapter, rain bird from the looks of it, can you take a picture of your old valve to confirm?
If you already have a replacement orbit solenoid, you could try unscrewing the adapter from the old solenoid to use with the new. Specifically, this is the part that looks like an adapter:
Hold on to it, and turn the solenoid counter clockwise to separate the two.
Otherwise try the rain bird solenoid:
https://www.homedepot.com/p/100563755