Yes Bill I built my own. No I didn't notch the stem and cap. Donald did that as he continued to use the modified cap for daily use. I picked up a cap at the salvage yard and made it a permanent part of the bleeder. I believe the cap would only need to be vented for use while driving. The tubing just slips over the valve stem, the important part about the valve stem on the cap is to be sure and remove the valve so you only have the stem. The valve stem on the pressure tank retains the valve. You can either apply pressure from a compressor or manually pump the handle and read the pressure at the stem with a tire gauge. Very simple, only took about 15 minutes to build, worked great.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.