If you have aux hydraulic lines simply hook into here. Adjust the pressure then activate the aux hydraulics and see what it reads, back it off or increase as needed. Your entire hydraulic circuit is linked, so the pressure change will effect lift, tilt, aux.
Note this problem could also be caused by a wore out hydraulic pump. If adjusting the relief screw on the hydraulic valve will not raise the pressure, then be sure to return the screw to the original position b4 installing a new pump or you can burst components in the hydaulic system which could result in injury and will result in damage
My 371 never had aux hydraulics with the quick couplers on the boom.
Instead I "T" ed into the hose for the lift of the main boom (hose attached to rean end of boom cylinder) then observed the max pressure the guage would reach when the boom hit the top and adjusted it to 1400 psi.
Note this problem could also be caused by a wore out hydraulic pump. If adjusting the relief screw on the hydraulic valve will not raise the pressure, then be sure to return the screw to the original position b4 installing a new pump .
The relief is about a 9/16" wrench size cap threaded over a 3/8 or so thread protruding from the valve. Remove the cap, the thread will have a screwdrive or allen slot on the end as there is no place to put a wrench. Where the screw meets the valve it will have a jamb nut to hold the screw in the corect position.
Hold the screw stationary, losen the jamb nut and turn the screw clockwise to increase the pressure, 1/2 a turn at a time, then check the pressure to see if it rises. If a full turn of the screw does not make a noticable difference in pressure something else it wrong and you need to find out what. (ie broken spring on relief valve, or defective hyd pump)
A 300 psi or more diffrence in max hyd pressure at low engine rpm verses hi engine rpm is often a indicator or a worn hyd pump.
Go to bobcat.com, historical specs and look up the 371, I believe 1400 psi is correct but please check
Also please send some pics of your repower and we will put them up in the repower section
Ken