I have the small Jet 1-A retracts in my Grumania F-100 with just over 20 flights on them.
These are air up, spring down units.

The problem that has occurred is that the main units are not lowering with consistency when I release the air pressure.

Has anyone had a simialr issue and what was your resolve to this problem?

I sent an email to Digitech and he has my issue resolved.

Thanks,
Bob

If Digitech has the problem resolved,what was the resolution to your sticking retracts???

Most of the time is is due to a Locking oleo or any other obstruction.
since the spring does the most work , it only needs a bit to go down.
so if you have any issues a good way to check is to when the retract stays up.
press against it , and if it clicks and releases , it is a sticky oleo , or a bend pin.
99% of all cases this is the problem..