Crud inside screen - how come?

[Davec]

I will also add my 3 hapence worth here....mainly for E61 manual lever group owners.

If you backflush daily with cleaner, you will wear the cam followers on the upper and lower valves (the inlet and preinfusion valve)....the cam being bronze not brass (or a harder alloy of brass), does not wear as much as the pins....but still wears a tad. Coffee oil really is not that effective a lubricating agent...I used to think it was, but experience has taught me this is not the case. You do need to lubricate regularly with the right product. Common signs of these cam followers on the valves wearing is some or all of.

• 1. Lever drops down on it's own sometimes when pulling a shot (top valve follower worn)
  
  2. Lever rises on it's own from resting position, sometimes a lot (bottom follower worn)
  
  3. When lowering lever to depressurise group, sometimes residual pressure (small amount is left in group, or group doesn't depressurise very violently, or lever has to be pushed home harder than usual. (bottom follower worn)
  
  4. Lever action is "notchy" (one or both pins worn)

Have a look for yourself...both pins are worn, the bottom much worse that the top. Now I know you don't have an E61, but the principles of requiring lubrication is a sound one.

Coffee oils didn't help, this machine was backflushed with cleaner every 3-4 weeks, but NOT lubricated with a proper lubricant...the wear on the bottom pin is obvious and the top is quite worn as well...machine 2.5 years old


By davec_coffeetime

New Valves pins...(cam followers) shown below


By davec_coffeetime