Hey Linda: The corrosion that causes the trim to bind appears on the trim
wire AND on the flexible housing in the stabilizer/elevator. The housing
inside the fuselage is aluminum tube between the stabilizer (rear bulkhead)
and the baggage compartment and generally does not cause a problem. However,
the housing on each end of the aluminum tube is flexible and made from
steel. When the airplane sits outside (especially in the rain) the corrosion
gets started. More than likely there was significant corrosion from years
prior to your ownership. There are bulkhead fittings at the rear bulkhead and
baggage compartment areas to transition the trim housing from the aluminum
tube to the steel flex housing. I have found that the rear housing often
needs to be replaced. This requires removal of the stabilizer.
You can attempt to replace the wire first with copious lubrication (I
recommend grease). If you can get the old trim wire out. It can probably be
removed by disconnecting the elevator and using vise grips and a hammer to
get it moving, then pulling it all the way out. When putting the new wire
in place, make sure the end is ground or filed round so that no edges will
catch on the flexible housings or the bulk head fittings. Then push it
through the housing while lubricating it with grease. If it hangs up, try
twisting it to get it past the obstruction. If you are able to get the new wire
past the rear bulkhead fitting, it will probably work just fine. If you
cannot get it in that far, you will need to replace the flexible housing in
the
stabilizer.
I agree completely with what Syd recommended. (Having your regular
mechanic do the work)
Best regards (& Merry Christmas)
Lynn Nelsen
In a message dated 12/17/2009 9:18:59 P.M. Eastern Standard Time,
[email protected] writes:
When I took my plane to the painters (day before Thanksgiving) the
trim was working fine. When I picked my plane up from the painters
on Monday, the trim wasn't working. It felt stuck: the control
handle bounced back when I tried to move it into position to (e.g.)
trim nose down, instead of its normal movement.
I took it back to him today. He said that when they'd put the
control surfaces back on, he found the cable was stiff (rusty?) so
they lubed it and then it worked, but after they finished the
painting it rained for several days and (since I couldn't some get it
in the rain), they put the plane outside the hangar (the next
customer's plane had to go into the hangar for stripping). They
figured it had rusted up again and was binding.
So in front of me, the painter & his AI sprayed some lubricant on the
tail end of the wire, where it comes out of its sheathing, took off
the covering of the trim control handle at the other end, so the
handle mechanism was exposed, then kept trying to force it to work.
Long story short, they broke the trim wire right up near where it
attaches to the trim control handle. (I'd guess it broke from metal
fatigue of him repeatedly trying to force it loose using the control
handle.)
So of course they're saying, "The wire was old and rusty and you're
better off replacing it with a new one." Well, now I don't have any
choice but to do so! I ordered the wire itself from Skyport; it is
not expensive, but the labor looks to be. The painter's AI said only
"less than one day" to install it, and that "if it's less than 3
hours, [he] wouldn't believe it." The young mechanic who usually
helps me at my home field isn't available (away for the holidays),
and I haven't yet been able to reach the AI who usually does my
annual so I don't know if he's in town. IF I'm stuck with the
painter's AI doing this
(a) how long should the labor take, and
(b) is there anywhere in our online resources that shows
how? I've looked in the Service Manual and can't find anything.
(Hartmut: is there anything on this in your photo collection?)
Linda
N3437H (Sky Sprite)
L.A.
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