Today, my Cessna 177RG's electric hydraulic pump failed. Upon departure, I selected gear up, and the gear failed to go all the way up, and the "pump running" light remained illuminated.
So, after exiting the traffic pattern, I selected gear down, which did nothing, of course. I shut off the master switch, as that shuts off the pump motor (the breaker is not pull-able) . I then pumped the gear down using the manual hand pump. Having done this many times during annual inspection, I knew instantly that it was working properly, by pump handle feel, the way it unlocks the nose gear and then gets easy. I watched the gear extend and lock into place. That was extremely satisfying!
I then selected the electrical master switch on and I was greeted by 2 green lights (normal, my airplane does not have 3 green lights) and, of course, I was very happy.
So, after an uneventful landing, I decided to take the motor apart and determine what the problem was. It seems one of the brushes had completely failed.
I found that interesting, as the brushes were both in good shape 2 years and about 80 hours ago. It seems to simply have disintegrated. Maybe it was arcing while in use. Don't know. After a bit of cleanup on the lathe, the armature looks to be in good condition and the brushes are easy enough to replace.
I am glad I took the time to re-seal the emergency hand pump and ensure that it worked perfectly. As it was in pretty poor shape originally.
So, after exiting the traffic pattern, I selected gear down, which did nothing, of course. I shut off the master switch, as that shuts off the pump motor (the breaker is not pull-able) . I then pumped the gear down using the manual hand pump. Having done this many times during annual inspection, I knew instantly that it was working properly, by pump handle feel, the way it unlocks the nose gear and then gets easy. I watched the gear extend and lock into place. That was extremely satisfying!
I then selected the electrical master switch on and I was greeted by 2 green lights (normal, my airplane does not have 3 green lights) and, of course, I was very happy.
So, after an uneventful landing, I decided to take the motor apart and determine what the problem was. It seems one of the brushes had completely failed.
I found that interesting, as the brushes were both in good shape 2 years and about 80 hours ago. It seems to simply have disintegrated. Maybe it was arcing while in use. Don't know. After a bit of cleanup on the lathe, the armature looks to be in good condition and the brushes are easy enough to replace.
I am glad I took the time to re-seal the emergency hand pump and ensure that it worked perfectly. As it was in pretty poor shape originally.
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