thanks for your help. I looked it up and yes I have MW pump.
I am starting to understand. I did not realize I could remove the valves without removing the two bolts. You have saved me from causing uneeded damage and expense.
So it is safe to unscrew the delivery valves. Will it help to soak these in a solution? I will look and see if the plunger is working. Do I need to torque these valves when reinstalling?