Upper dishwasher control arm wobbling and hitting roof

Dishwasher Repair
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1

During the normal wash/rinse cycle the upper control arm of my Maytag MDB6000AWW dishwasher has recently started wobbling as it spins, hitting the roof of the dishwasher and causing a thumping sound.

Question is -

  1. Can it be adjusted in place?
  2. If not, does the arm need to be removed and a plastic seal replaced?
  3. Any other possible explanation?
2

Here are the parts: AP6015216AP6013632 AP4009409. You have to pull the dishwasher out ti order to replace them.