PT20J

There are two pertinent Mooney Service Bulletins: M20-264 (AD98-24-11) to replace aileron control links with gusseted parts. This was done on my airplane in 1998 by installing the Mooney factory kit. M20-289A to change spacers in the links to prevent interference with the landing gear bellcrank. This was done on my airplane in 2005. Since I recently purchased the airplane, I have no way of knowing how long this rubbing has been going on. It occurs at wing station 133.0, and looking more carefully at the IPC, I see that the tube is actually called AILERON CONTROL TUBE ASSY at that point rather than a CONTROL LINK (the control tube bolts to, and is an outboard extension of, the control link). I've attached a picture of the rub point with most of the grease wiped off. Next thing to check is that the spacers are correctly installed per M20-289A. The Service Manual calls for using MIL-G-23827 grease on the guide blocks. Traditionally this was Aeroshell Grease 7. This grease spec. has been superseded by MIL-PRF-23827C which specifies Type I (metallic soap thickener) and Type II (clay thickener) greases. The two types are not compatible. Aeroshell 7 is Type II. I found evidence of at least three different greases having been used on my guide blocks. I cleaned it all off with Stoddard solvent and regreased with Aeroshell 7. It only requires a thin coat. There really isn't any way to hold a lot of grease around the thin phenolic blocks, and forcing a lot of grease in there just makes a mess that collects dirt. Skip

During annual inspection, I noticed a rubbing noise emanating from within the left wing during the last inch or so of the left aileron travel in the up direction. Some investigation revealed that the sound comes from the aileron control link rubbing on the aft side of the phenolic guide block at wing station 133.0. The paint on the tube is rubbed off, but the tube appears undamaged and there is no metal-to-metal contact. I cleaned all the wing guide blocks and regreased with Aeroshell 7 to no effect. The right aileron does the same thing to a lesser extend, but I haven't opened up the right wing yet to verify that it's the same guide block. I'm wondering if anyone else has experienced this and found a way to correct it.

I removed the trim wheel and gearbox assembly from the airplane to examine it. The steel trim wheel shaft runs through a hardened brass bushing. In my case, both parts were worn causing the wobble. The service manual doesn't mention lubricating this part -- probably because there really isn't a good way to lubricate the bushing without removing the chain, driving the roll pin out of the sprocket and removing the trim wheel/shaft and applying grease. A better design would have been to use a standard size oilite (oil impregnated sintered bronze) bushing. I ordered a new shaft and bushing and plan to drill a small hole in the top of the bushing. That way, at annual I can remove the plastic chain cover and pump some grease in with a grease needle. Skip

I've noticed a bit of wobble in the trim wheel on my M20J. It wobbles maybe a quarter inch left to right when the wheel is grasped at the top or front. Anyone know how much wobble in the bushing is normal?