23) Filling the Landing Gear Hydraulic System

(Early model 337’s and 0-2’s)

There are numerous places on your aircraft where small hydraulic fluid leaks can occur. Many early model Skymaster landing gear problems are caused by low hydraulic fluid levels in the power pack. The only way to be sure the system is full of hydraulic fluid is when fluid drains out the overboard tube at the belly. Even with the sight glass, it is difficult to determine the fluid level. Because of this, we recommend that the system be manually filled with hydraulic fluid often.

Learn how to fill the hydraulic system on your own aircraft. Remove the screw and bleeder type fitting and place the end of the plastic tube inside the hole. Use a plastic squirt bottle or squirt can with small plastic hose. Pump hydraulic fluid until it starts to drain out the drain tube on the belly. You will learn that you need to hold the tube inside the fitting tight with a rag or paper towel to keep from getting hydraulic all over. Do this often to keep your hydraulic reservoir full. How often, maybe every 2 weeks to start with, hydraulic fluid is cheap compared to landing gear problems. We have noticed while using a hydraulic power cart to conduct retraction tests, sometimes the cart seems to keep hydraulic fluid and the aircraft system will need to be refilled. On late model Skymasters, the hydraulic fluid level is checked and filled at the dipstick, and we recommend it be checked and filled often.