i am new at this and have been haveing trouble sucking a ball and with all the great help on here have fig out it is my wear parts on the rock valve i know the kidney seal is shot what eles should i look at changing i was thanking the pressure spring as well the plates all look good no big pits or nothing like that is noticeble is tha all the wear parts to look at  looking at the book i see a ring support by the pressure spring do i need to replace it as well  thank u for all your help it is greatly appreciated

Pressure spring, cutting ring and kidney seal for sure. Wear plate should be smooth with no big grooves. Small grooves are ok for awhile.

Last time I changed a cutting ring I didn't change the pressurespring. If it feels smooth and not dammaged we don't always change it.

Just a thought on PM,make certain you spray hopper oil and cycle 1-2 times at end of each washout,your kidny seal will love you.