Narrative:

I recently purchased this supercub on wip 2100 amphibious floats. It has roughly 35 hrs and 2 months since annual and complete service. Floats have roughly 300 hours of total use; and were new in 1998. After making several landings on the a river; and parking on the river bank for several minutes in an estimated 7 mph current; I flew back to [my home field] to land at the airport (something I have done on at least 5 other times). Upon selecting the gear to the down position; my gear extended except that the right main extended only halfway. I selected the gear up; and the right main stayed half extended. I then tried the manual hand pump procedure with the same result. I [advised ATC]; burned off gas/weight mostly on the right side for an hour; and with no grass runway available; opted to land on [a paved] runway with a slight right crosswind. I was aware of a grass runway within the area; but without any assistance; and approaching thunderstorms; I chose to stick with [my home airport]. After a fly-by tower confirmed that my gear was extended below the float bottom; but was not fully extended. I knew it was not down and locked; but it had some hydraulic pressure holding it below the float bottom. I suspected that with weight on it; it would press back into the wheel well. I landed on the three extended wheels; and used my left brake to slow; keeping the weight off my right main. As the aircraft settled onto the right main; it slowly pushed the right main tire back into the wheel well. I was almost completely stopped before the heavy duty keel skid contacted the hard surface. The heavy duty keel skid is designed to protect the floats; so there was no damage to the floats; and no needed repair to the keel skid as it served its purpose and lost little or no surface.it was discovered that grease from servicing had gotten into the trunnion track where only dry teflon lubricant should be. Sand/silt that I had seen being whipped by the current past and into my wheel well found a place to sit; dry; and blow around in the gear to mix with the grease and block the gear rollers. There was also a leak discovered on the right actuator; there had been no sign of a leak prior. I have also discovered that there was a service letter issued by the manufacturer that applies to my floats; issued in 2002; (not required to be done but was free at the time of issuance) that changes the gear design to prevent clogging. Today this modification would cost about $6000. An expensive modification if I were to choose to do it. I am relatively new to floats; and it is my fault for not catching this during the prebuy/annual; or knowing that it was a danger. Had I known this was the case; I would have changed the purchase. In the meantime; I will have to prevent the clogging on my own by cleaning and inspecting.

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Original NASA ASRS Text

Title: PA-18 pilot operating an amphibious float-equipped aircraft reported the right main gear failed to fully extend. Later inspection revealed the gear rollers were fouled with grease and dirt.

Narrative: I recently purchased this Supercub on Wip 2100 amphibious floats. It has roughly 35 hrs and 2 months since annual and complete service. Floats have roughly 300 hours of total use; and were new in 1998. After making several landings on the a river; and parking on the river bank for several minutes in an estimated 7 mph current; I flew back to [my home field] to land at the airport (something I have done on at least 5 other times). Upon selecting the gear to the down position; my gear extended except that the right main extended only halfway. I selected the gear up; and the right main stayed half extended. I then tried the manual hand pump procedure with the same result. I [advised ATC]; burned off gas/weight mostly on the right side for an hour; and with no grass runway available; opted to land on [a paved] runway with a slight right crosswind. I was aware of a grass runway within the area; but without any assistance; and approaching thunderstorms; I chose to stick with [my home airport]. After a fly-by Tower confirmed that my gear was extended below the float bottom; but was not fully extended. I knew it was not down and locked; but it had some hydraulic pressure holding it below the float bottom. I suspected that with weight on it; it would press back into the wheel well. I landed on the three extended wheels; and used my left brake to slow; keeping the weight off my right main. As the aircraft settled onto the right main; it slowly pushed the right main tire back into the wheel well. I was almost completely stopped before the heavy duty keel skid contacted the hard surface. The heavy duty keel skid is designed to protect the floats; so there was no damage to the floats; and no needed repair to the keel skid as it served its purpose and lost little or no surface.It was discovered that grease from servicing had gotten into the trunnion track where only dry Teflon lubricant should be. Sand/silt that I had seen being whipped by the current past and into my wheel well found a place to sit; dry; and blow around in the gear to mix with the grease and block the gear rollers. There was also a leak discovered on the right actuator; there had been no sign of a leak prior. I have also discovered that there was a service letter issued by the manufacturer that applies to my floats; issued in 2002; (not required to be done but was free at the time of issuance) that changes the gear design to prevent clogging. Today this modification would cost about $6000. An expensive modification if I were to choose to do it. I am relatively new to floats; and it is my fault for not catching this during the prebuy/annual; or knowing that it was a danger. Had I known this was the case; I would have changed the purchase. In the meantime; I will have to prevent the clogging on my own by cleaning and inspecting.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.