chrisch
Contributor
On the Hollis 500SE, adjusting the cracking pressure (indeed, all servicing if you do your own) is extremely simple. Also, the service manual is available for download on-line.
here: http://www.hollis.com/media/wysiwyg/HO/manuals/500SE_12-4095_r04_11-25-14.pdf
Cracking is a single screw adjustment (shown in manual as 1/4 turn primary, 1/2 turn octo) between lever and diaphragm.