Exhaust Slip Joints Need Lubrication!
Sealless exhaust slip joints are not permanently lubricated. RAM recommends lubricating sealless exhaust slip joints during the Annual Inspection of the aircraft, and anytime they are removed for other engine work. Lubricate them immediately if they are suspected of binding.
Essentially maintenance free when compared to the older style slip joints, sealless slip joints still need lubrication. Lubricating a few sealless slip joints is still a bargain when compared to the expense of re-packing the carbon type seals or replacing the bellows units.
When sealless exhaust slip joints are left unattended, the consequence can be binding. Binding leads to increased engine vibration being transferred throughout the airframe. Always inspect the slip joint units for freedom of movement and no distortion.
To lubricate properly, separate the two halves and clean them thoroughly. Coat both sealing surfaces with Never-Seez compound, or an equivalent anti-seize compound. Never-Seez compound contains fine particles of nickel, graphite and other additives.
Never-Seez is manufactured by:
Bostik in Middleton, MA 01949.
Bostik Catalog number is NSN165.
It is sold in a 1 lb. can.
Never-Seez is also sold by RAM at: Never-Seez