View Single Post
Old 02-07-2012, 07:25 AM
Pat Hatch's Avatar
Pat Hatch Pat Hatch is offline
Join Date: Jun 2006
Location: Vero Beach, FL
Posts: 915
Default Gear Box O-ring

Gary, did you happen to find the little O-ring that goes into the recess or counterbore in the gearbox? You can see this recess in your 6th picture down. I recently did this and was careful to re-insert the O-ring into this recess upon re-assembly. I think this O-ring is what is supposed to seal the grease and prevent it from getting slung out of the gearbox. I doubt if it does much in the way of preventing the grease from migrating through the motor bearing all the way to the commutator.

For what it's worth, I found no grease contamination in my motor, just the brush carbon tracks on the commutator that I cleaned up as you described. My flap motor operation has been flawless, I just did this cleaning as preventative maintenance during my last condition inspection. Just for background, Van's switched from the Motion System motors to the Pittman motors in 2002, and according to Van's newsletter about this problem, it was thought that the last of the Motion System motors were the culprits. I have one of these and mine appears to be fine; besides, the Pittman motors appear to be the exact same motor. I just think it was a change of ownership and not a change in the motor design. The blame has also been attributed to over-servicing the gearbox with grease in isolated instances. This grease contamination remains a mystery as far as I'm concerned.
Pat Hatch
RV-4 (Gone to RV heaven)
RV-6 (N44PH - Flying)
RV-7 (Sold)
RV-8 (Builder & Avionics Installer) Trim Relay Boards/Flap Actuators (Photography)
Track Me
Reply With Quote