PT20J

Before changing anything, I’d have someone move the nose wheel with the tow bar while watching the mechanism to try to figure out what’s causing the coupling between the rudder and the brakes. I’d especially watch the pivot point at bolt 8. The brake bell crank and rudder torque tube both pivot at this point. That’s the only obvious source of coupling that I can see. Skip

The biggest problem I have with the A3B6 (which was never a problem with the A3B6D) is getting a wrench on the filter. I use a 1" racheting box end wrench which works fine. I tried all sorts of adapters to get my torque wrench on it (none of which worked) and finally just started tightening 3/4 turn like @jetdriven suggested - just like a car. @M20Doc, How do you torque the darned thing? BTW, it's not that hard to get the suction screen out. It's safety wiring it that will drive you nuts. But experience and practice is everything. My IA did it in less than 5 minutes with no blood and only a little swearing when we did the annual. Same when he safety wired the prop. Point is: after a a couple of oil changes you won't think it's so hard anymore. Just hope you never have to remove the prop governor! Skip

Clarence is correct: The adjustment I showed above will lengthen or shorten the piston rod for the master cylinder to change the pedal angle. It is the only adjustment that I am aware of. I don't really know if it has any effect on your problem, but since replacing the brake cylinders seems to have initiated the issue, it's where I would start. The rudder pedals have two connections: Item 4 for rudder control and item 5 for the brakes. The distance between where the two connect on the pedal is the same as the length of the arm on item 7. So, mechanically, the pedal and items 4, 5, and 7 form a parallelogram such that pushing on a pedal without rotating it will rotate the rudder torque tube without applying the brakes. Another possible way things could have been messed up is if rudder pedal extensions were installed perhaps incorrectly. Skip

Yes

By golly, I think you’ve figured it out! I never would have thought of that. Edit: Sorry, too much eggnog

Paul, Curious to know what magnitude EGT swings you usually see with valve issues. Skip

There is an adjustment to the lengths of the master cylinder piston rods. There is no description of it I could find in the S&MM for my M20J when I had to tweak mine to get the pedal angles right after installing the 3" pedal extensions. There should be some free play in the pedal before the brakes go solid. If you remove the left exhaust cavity an examine the linkages it should be fairly obvious what's gone wrong.

Just email technicalsupport@mooney.com. They are very responsive to specific questions in my experience. Skip

I don’t carry many tools. I have a hangar full of tools and always seem to need another, so I figure it’s unlikely that whatever tools I might lug around would get the job done. Same with parts. If I knew enough to know what was going to fail, I’d replace it before I flew. I ditched the flight bag for Foreflight on my iPad and iPhone. I do tote around oil, chocks, tiedowns, cowl plugs, pitot cover, canopy cover, GATS jar, plastic polish and microfiber cloths, and a tire pressure gauge. Up front I have a pulse oximeter and flashlight within reach. And I have backpack with survival gear - just in case. Skip

Well, obviously it shouldn’t. But you said the master cylinders were replaced with parts that are different than the original so maybe something got messed up then since the brakes are attached to the rudder pedals. The point is that something unusual seems to be going on and it’s pretty hard to guess what it might be. But if you open it up and look at the motion it should be immediately obvious it it’s something to do with the brakes. Skip

I think you are right and it should be fine. I’m assuming since there is no aft spec in the SB or my M20J service manual that it doesn’t matter. But still it would be interesting to see what the factory says.

The M20J Service Manual has a note about it. Not sure about earlier manuals.

I'm still puzzled since the Service Manual doesn't show a max rearward dimension. Here's a thought: The new Mooney website has a forum with a section for Technical and Maintenance Tips which they have promised to monitor. Why not post this there and see what happens? Skip

I think "recommend" is perhaps a little strong. LW-16702 is required by AD for certain engines with smaller faced tappets. Lycoming "approves" the use in all it's engines. (SI 1409C) Aeroshell and now Phillips make oil with the additive in it approved by the FAA as meeting the AD so you don't have to mix it if you have an engine that requires it.

This should be easy to figure out. I’d remove the cowling and left exhaust cavity (yes, I know there’s no exhaust pipe on the left side, but that’s what it’s called). This will expose the master cylinders and linkages. Then I’d put the plane on jacks to get the nose wheel off the ground so that it is easy to move and observe the action of the mechanism while moving the nose gear from stop to stop. SkIp

Well, the Service Manual says it needs to be shimmed if the axel is more than .06 forward of the plumb line, but it doesn’t list a limit aft. More caster will make it track better. As long as retract tests are good and you have wheel well clearance it’s probably fine. Now I’m going to have to measure mine someday - it steers fine, but I have no idea how far aft it is. Skip

I hear you. Sometimes you just got to go with the flow

Kind of late now, but IIRC Precision says the flow divider is field serviceable. As you said, there’s not much to it.

You mentioned checking the throttle and mixture cables can drive the associated control arms to the stops on the carburetor. Did you also check that the prop control can drive the governor arm to the stop with about a 1/8" cushion before the control hits the panel? The prop governor should not affect the rpm during a static run up. The prop should be sitting on the low pitch stop and the rpm (assuming full engine power) should be within 100 rpm below redline. Often it will be about 2650. As you begin the takeoff roll the airflow will want to speed the prop up and a properly adjusted governor will stop it at 2700. Also, it's always a good idea to check that the tach is accurate. I assume that your A&P has an optical tach for that purpose. Skip

If Moog bought them, they must see value there. I'd be a LOT more concerned if Garmin bought them. Skip

Everyone I know here on the west coast sends their mags to Cliff Orcutt at Aircraft Magneto. He does great work and stands by his customers. He quit doing the dual mags though when some parts got hard to get. Skip

Are you sure that the servo is bad? Assuming that the engine is putting out rated power, I would expect a FF that low to cause elevated head temperatures. I'd verify the accuracy of the FF indicator. Transducers can read low as they age. Also, I'd contact Al Jesmer at Precision Airmotive (now part of Tempest) and discuss it with him. I've found him very helpful. alan@tempestaero.com Skip

Anthony, I think that the 100 means 100/130 (green) not no lead. The lead was understood until the 100LL was introduced. Skip

Interesting idea. It would be an easy check to have someone in the cockpit watch the pedals when someone swivels the nose wheel.

I believe that the fixed timing is set for MBT (Maximum Brake Torque) at rated power. Everything else is a compromise. The compromise isn't bad at higher powers and ROP -- should only be a couple of percent power deviation over the ROP range. At lower powers (high altitudes for a normally aspirated engine) and LOP (increased burn time throws timing off optimum) more advance is beneficial. A lot has made the effect of rpm because supposedly the burn time is constant so increased rpm gives a shorter amount of time (or crankshaft angle ) for the mixture to combust and therefore requires more advanced timing. I've been reading several textbooks lately and it turns out that this effect is not 1:1 since increased rpm increases the turbulence in the cylinder which has the effect of decreasing burn time. Over the narrow range of cruise power rpm used in airplanes, the effect is really very small. Which is another reason that the fixed timing works. Skip