replying to Bob, DaveRepair wrote:
My tubo88 also had an erratic reduced flush because the black washer below the
blue one did not always expose the air leak holes because its bore was too
large for the thicker section of the piston rod. The simple solution was to
swap the black and blue washers around as the blue plastic washer will catch
on the thicker section. Dudley should provide a black rubber washer with the
correct bore or made of a rubber that doesnt expand after a few years

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