Since my checkvalve was leaking there was very little pressure on the system as the car had been sitting overnight since it was started. I do not know the correct procedure for venting a pressurized fuel system but I would wrap a rag around one of the clamped hoses and loosen it a little to relieve the pressure and catch the fuel.
88 300E 225K Sold
2000 C230K Totaled @103K
2003 ML320 140K Granddaughters Limo
2009 E350 4Matic Sport 37K Sold
2011 ML350 44K