Here are some useful links regarding hydraulic system repairs.
Hyd jack repair
Keystone Montana RV Owners Group
By Ken Anderson August 26 2019
https://www.facebook.com/groups/2740...2921538431587/
Hydraulic
Plug and cap Size for the JIC37 fittings ...
3404C-04 Cap
2408-04 Plug
Size is 1/4 Inch for cap and plug
Hydraulic pump/ram repair
https://www.montanaowners.com/forums...ad.php?t=82140
https://www.rvupgradestore.com/16757...045-167576.htm