6890N GC w/ 5977A MSD air leak

6890N GC w/ 5977A MSD turned on for first time in 6 years. Can’t stop/find source of air leak. Someone suggested changing the MS door seal? What is that part number of proper terminology so I can look it up to order.

  • The part you are looking for is a side plate o-ring 0905-1442. 

  • Carefully remove the old O ring. There's a spot in the lower right hand edge that has an opening where you can very carefully pry it out. Do not scratch the aluminum manifold.

    Use a solvent-dipped cotton-tipped swab to wipe out the entire O ring channel. Use a solvent-dipped lint-free cloth to wipe the sealing surface on the side plate/analyzer door.

    To install the O ring, hold it in your hands pulling it equidistant between them, then follow this diagram.  You can't put it in one spot and then work your way around as it stretches it just enough so you end up with a big excess.

    This O ring should be replaced once in a while, at least every three or four years.

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