Hey duodeluxe the letters are mc and the problem is exactly what you said after sitting over the weekend the brakes have no pressure, we have tried bleeding the brakes and after we do that they work fine but if the truck sits the pedal goes away. I talked with some old clark guys and they said if we are going to do the brakes we might as well do the trans also, I hear that you can use compressed air to help bleed the system but to me this sound crazy since it is air I am trying to eleminate. Any way I agree clark brakes are the worst, any advice I would appreciate.