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I have a school report about the lubrication on the shock strut and I was wondering if there is a specific type of lubrication they apply it on.

This is for Cessna 150-152

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  • $\begingroup$ cessna 150-152. $\endgroup$ – Todd Baker Feb 25 '19 at 10:08
  • $\begingroup$ What do you mean by lubrication? Greasing fittings? Or applying something to the strut chrome? $\endgroup$ – John K Feb 25 '19 at 14:51
  • $\begingroup$ I heard that they apply something on the outside part of the shock strut or some kind of a fluid? $\endgroup$ – Todd Baker Feb 26 '19 at 10:27
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Oleo struts and brakes used on light aircraft use MIL-H-5606H hydraulic fluid (the red stuff) as the internal damping agent/lubricant (be sure to check the manual anyway). It's a normal practice to clean the exposed chrome of the shock strut (it should be done with the tail held down to extend the strut all the way) with a clean cloth, then wiping it with a cloth with a little bit of 5606 to leave just a very light film to help lube the scraper and seals the next time the strut compresses (once that's done there is the film of internal fluid left behind by the seals).

The biggest enemy of oleo struts is silica particles (which are very hard) from outdoor dust which sticks to the chrome surface because of the fluid film left behind by the internal seals. The silica collects in the seal cartridge and acts like lapping compound, accelerating wear (this is why desert operations are the toughest environment overall on any airplane).

As the strut ages and the seals wear and slowly start to leave behind more fluid each time the strut extends, dust collects faster and the whole process speeds up, so the strut should be kept clean as much as possible depending on how dusty the local environment is.

If it's your own plane, you should learn to do the published procedure yourself, because nobody else is going to do it between annuals. If you're renting the plane, that's the owner's problem, and you just do your normal walkaround inspection.

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By law, the FAA requires the POH to provide basic servicing instructions and approved lubricant. The exact information provided depends on the year of aircraft, older aircraft having less information (the FAA became stricter over time). See: C150 POH Manual

For the C150-152 the Pilots Operating Manual (POH) provides all necessary basic maintenance information in two places - "Servicing Intervals" and "Servicing Requirements" (I'll leave it upto you to see if the nose strut is applicable).

There is a fundamental rule all teachers and instructors tell new or potential pilots, "... READ THE MANUAL!"

I am an A&P and Pilot. By FAA law the POH must provide the proper servicing lubricant type - READ THE MANUAL. The information is located on the next to last page of the manual I cited! It is against the law to use any lubricant not approved by the mfg or FAA. Motor oil is commonly wiped on the strut but unless there is a SB (service bulletin) from the mfg that is not legal.

The FAA prohibits the unauthorized mixing of dissimilar brands or types of lubricant except for motor oil (By law, motor oil must be able to be mixed). In this case the POH provides the authorized lubricant to be used on the strut.

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    $\begingroup$ The Manual only discusses checking the strut for proper inflation. Otherwise, it refers one to the Maintenance Manual for "complete servicing, inspection, and test requirements" which are "available from your Local Cessna Service Station". $\endgroup$ – CrossRoads Feb 25 '19 at 14:06
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    $\begingroup$ The approved lubricant for the strut is located on the next to last page of the manual I cited. READ THE MANUAL! $\endgroup$ – jwzumwalt Feb 26 '19 at 8:49

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