[Loosenut]

I recently had and still have issues with my mastercylinder on my 2000 EC300. I learned a trick. You will need a large syringe to back bleed the system. I was able to get an instant firm clutch by removing the snap ring that secures the piston in the MC bore and pulling it out just enough to allow fluid to easily flow. I forced plenty of fluid through to ensure no bubbles and a huge puddle in the pan on the floor. I then pressed the piston into place and installed the snap ring. I closed the bleed valve and I had a firm clutch with no pumping. It's more effort than the nomal methods, but it worked great.