The Glasair Technical Support Desk was recently contacted by the builder of a flying Glasair II who had a hydraulic fluid leak around the shaft on the nose gear hydraulic retract actuating cylinder. Before sending him the rebuild kit for the actuator I suggested he check the Hydraulic Actuator Washer (this washer retains the hydraulic actuator poly-pak seal) to verify if it was flat or “bulged out”. The builder confirmed the washer was bulged out and this was the cause of the leaking seal.
The Hydraulic Actuator Washer currently installed in all Glasair Hydraulic Actuators is fabricated from stainless steel. Some earlier model Glasairs were supplied with Hydraulic Actuators which had an aluminum washer installed. The aluminum washer is adequate for normal operation but when subject to higher than normal operating pressures (such as thermal expansion and landing accidents) it has the tendency to “bulge out” in the area of the seal it is retaining.
It is highly recommended that all aluminum washers be replaced with the stronger stainless steel washers. Builders and operators of Glasair RG aircraft should inspect each hydraulic actuator to verify that rod seal retaining washer is made of stainless steel. Any washers that are found to be aluminum should be replaced with the appropriate stainless steel washer. Probably one of the easiest ways to confirm whether the washer is aluminum or stainless steel is to use a sharp pointed scribe and attempt to scratch the washer. An aluminum washer will be much softer and will scratch easily.