Corroded NLG actuator rod caused loss of hydraulic fluid

[scottrsellers]

Abrasion damage to o rings from corrosion on the NLG actuator rod caused all hydraulic fluid to drain onto the hangar floor while parked. See rod pictures below.

IMG_4183.jpg (8.62 KiB) Viewed 78 times

IMG_4181.jpg (6.47 KiB) Viewed 78 times

IMG_4182.jpg (7.46 KiB) Viewed 78 times

[jelecroy]

I had to replace our NG actuator a few years ago. The actuator does not have a scraper to keep dirt away from the seal o-ring, so any dirt or dust that collects on the oily shaft gets deposited on the first obstruction it comes to, which is the outer o-ring. The abrasive dirt then works on the shaft when it wiggles a little under normal fore and aft loads in taxi. Eventually that cuts a groove into the actuator rod. Unfortunately, the actuator piston/rod is just soft stainless steel, not hard chrome plated like a real hydraulic cylinder would be, so the abrasion can happen faster than I might like.
My advice is to take the actuator cap off every couple years, clean the area around the shaft exit, and install a new clean o-ring. It's a nuisance, but if you do that and don't operate off unpaved strips the actuator piston will likely last decades.