Skywagon 185
Flight Crew Private
Flight Crew Last 90 Days 25; Flight Crew Total 500; Flight Crew Type 200
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Returned To Departure Airport; Flight Crew Regained Aircraft Control; General Flight Cancelled / Delayed
Aircraft
Cessna 185 on amphibious floats. While taking off from seaplane base; at approximately 30 knots; the right landing gear hydraulic system failed dropping the right wheel(s) into the water pulling the plane hard to the right. I pulled power and applied full backpressure on the yoke when I felt the issue begin. The takeoff was aborted. The plane did not sink or take on water. I was able to taxi the aircraft under its own power out of the lake and back to the seaplane ramp. The electric gear activation no longer worked; but I was able to use the manual landing gear pump to lower both left and right gear fully before driving up the seaplane ramp.No injuries and no obvious damage to the aircraft. No other boats or planes were in the area. I was the only person in the aircraft. I had flown earlier in the day [for] a 40-minute flight; had lunch at FA1; and was planning to return to my departure airport when the failure on takeoff occurred. I had not consumed alcohol and I am not taking any medication. I attempted to contact several mechanics to see if the issue could be repaired; but there were no mechanics available. The aircraft will be parked on the  plane/boat ramp until sometime after; when I can get a mechanic to look at it and determine the cause of the failure. However; during the previous week while the aircraft was hangered; the aircraft was covered with dirt and debris from an asphalt-cutting project that occurred 10-20 feet directly in front of an open hangar where the aircraft was parked. I will have to wait for a mechanic to determine the cause; but it could be that dust or debris from the asphalt cutting contaminated the landing gear hydraulics either causing or contributing to the failure.
C185 pilot floatplane reported while on waterway takeoff; the right wheel dropped; due to hydraulic system failure.