rear cowl flap motor issue

[Don Nieser]

We carry new, repaired and as removed cowl flap motors for all 337 aircraft. Please call Don for pricing. We try to beat any other price. 405-503-4686 or e-mail; nieser.02.337parts@juno.com.

[B2C2]

The plane is in for annual now. After the general inspection we will have a look at the wiring to the motor. I took a look at this once I had it back in the hanger and there is one wire that is loose and has about 1/2inch of clear plastic sleeving that is over the tefzel wire that is missing, and the tefzel wire in that section seems kind of flimsy to me, so perhaps a broken connection internally. this should be easy to see by wiggling the wire while turning on the motor switch. That is a two man job however so I will do this with the mechanic once we are ready to dig into it in a week or so. thanks for all the suggestions on repair of the motor should it come to that. One of the folks is right down the road form me. I also have the STC for cable actuation of the front flaps already, so thankfully only one motor to worry about.

Ben

[B2C2]

Well, extensive wire wiggling failed to produce a hiccup in the motor behavior, so I have asked my mechanic to pull the motor and we will send it to Georges Electrical in Sacramento. He uses them a lot so was comfortable with this path. They are right down the road as well so that's nice. Its still possible its something else but since the plane is out of commission anyway I figured I would do this to rule out a motor problem in the future in case it shows up again.

[B2C2]

So this issue has been resolved. It turns out that there is a connection to the brake on the rear flap motor right where the wires enter the motor case. the wires themselves (Red, Black and White for the brake) are wrapped in a braided shield that is tied to ground. It looks like there was originally some sort of insulation applied to the connection, but this wore off over time, allowing the shield to occasionally contact the exposed terminal and actuating the brake. We found this when after reassembly the mechanism was still intermittent. We pulled the motor out and while we had it connected but not tied to the mechanism we wiggled the lead entering the motor and it made the motor start and stop. Inspection found the exposed terminal issue. We applied some high temp silicone to the exposed connection and put everything back together and it works properly. So if you see this problem, try wiggling the leads where they enter the motor case and see if this causes it to be intermittent. This lead is typically tied to the motor case with a zip tie or clamp for strain relief, so it normally doesn't move much but apparently enough to create the problem.

[hharney]

Thanks for the report and glad to hear you chased down the issue. This is a good thread for those others trying to troubleshoot the CF motors