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Rudder bushing kit for 1946 140

Posted: Mon Mar 16, 2020 10:03 am
by 6352
My 140 (serial 11097) needs new rudder bushings as there is some play in the rudder hinges, more than in several other 140s and 120s I have checked. Looking on aircraft spruce, there are quite a few rudder bushing kits with different prices and all describe themselves as appropriate for the 140. Does anyone know which kit is really the one to get?

Re: Rudder bushing kit for 1946 140

Posted: Mon Mar 16, 2020 12:22 pm
by 6643
First, you need to make sure you understand what your problem is. My experience is that many, if not most, issues are really due to enlarged holes in the hinge sections attached to the rudder itself. The lower hinge is part of the bellcrank, and also is the thrust surface carrying the weight of the rudder. It tends to wear through on the upper section.

There's a a pair of AN3 bolts that go through each hinge. They have steel bushings, 1/4" OD, that are clamped between the top and bottom rudder hinges, to prevent movement of the bolt and wear of the hinges. If the bolts are not tight the holes wear.

The steel bushings run in bronze bushings that are pressed into the hinge sections attached to the stabilizer, and should be the only part that wears. The steel bushings are unobtanium expensive. The bellcrank is available from Univair. Not sure about the upper hinges.

Not an answer to your question, but a place to start.

Re: Rudder bushing kit for 1946 140

Posted: Mon Mar 16, 2020 6:15 pm
by 6352
Thank you John, By pushing on the aft edge of the rudder, there appears to be play in the top hinge only, and I had assumed that was due to the bronze bushing wear there. But will look closer look and wiggle more tomorrow. Thanks for the advice.

Re: Rudder bushing kit for 1946 140

Posted: Mon Mar 16, 2020 6:23 pm
by 6643
Put your finger on the bolt head where it meets the hinge and rock the rudder, If there's movement between the bolt an hinge the holes are enlarged. Otherwise, it''s easy enough to take the rudder off and check the fit between the steel bushing and the bronze one.

Re: Rudder bushing kit for 1946 140

Posted: Mon Mar 16, 2020 10:06 pm
by 6352
Thanks again John. I really appreciate your advice on the forum. Stay healthy!