Replacing over center link bushings to re-establish clearance to main gear trusses

[MB65E]

Amazing work!!

I'd caution the "higher is better," No sense stressing the system. I think a lot of the manual gear collapses happen right after the gear is "adjusted because it was low". The nose gear tubing, standoffs, and fittings are probably weaker than they were when they left the factory. Stuff bends. 

What did the nose tensions come out to be?? They changed when I adjusted the mains. 

Well done!

-Matt

[Vance Harral]

This is an electric gear model, not manual.  Nose gear rigging is measured by travel delta from unloaded to locked.  Ours was roughly in the middle of the 0.030 - 0.070 range for ITT actuators.  Everything in the system is connected, so I understand how changes to the main can affect the nose and vice-versa.  But ours didn't change much.

As for "higher is better", I would not have adjusted the mains toward higher preloads if they were already in range, even at the low end.  But two turns of the rod ends was below the minimum limit, so I went with one turn even though it's on the high side.

[MB65E]

4 minutes ago, Vance Harral said:

This is an electric gear model, not manual.  Nose gear rigging is measured by travel delta from unloaded to locked.  Ours was roughly in the middle of the 0.030 - 0.070 range for ITT actuators.  Everything in the system is connected, so I understand how changes to the main can affect the nose and vice-versa.  But ours didn't change much.

As for "higher is better", I would not have adjusted the mains toward higher preloads if they were already in range, even at the low end.  But two turns of the rod ends was below the minimum limit, so I went with one turn even though it's on the high side.

Great!! Sorry- that was more of a general  observation I had for others.  

It'll feel good landing knowing Gear is in great shape!!

I'm glad Mooney doesn't require gear overhauls in the manual. However, it's sure nice to pull everything apart every once in a while. At least it's not a Falcon! 

-Matt

[RLCarter]

Here is the torque wrench I used, with the memory pointer reading the brake over torque is easy

http://www.aircraftspruce.com/catalog/topages/dialtypewrench.php?clickkey=3558

[Vance Harral]

Feel like I should put a bookend on this topic, though there isn't much else to report.  Test flight was uneventful with no landing gear issues.

Some final notes I recorded about R&R'ing the gear:

• The best setup for removing the trunion bearing bolts at the rear of the wheel wheel is a 3/8" socket driver, a 6" extension, and a universal joint between the extension and the driver (not between the extension and the socket itself).
• By far the most annoying bolt/nut to reinstall is the one that connects the gear spring assist bracket to the gear leg.  Everything else is a distant second - even the bolt that connects the retract rod to the bellcrank in the belly.  There's just no way to get your fingers up above the trunion to install the spring bracket bolt in the proper direction, and no set of pliers in most tool chests with the correct angle to hold the bolt, no matter where you put the gear in the retract cycle.  I coulda used a set of pliers with a side (not perpendicular) bend, or maybe an 8-year old with small hands.
• Pay careful attention to the direction of bolt installation in the parts manual - I got a couple of them backwards on the first pass and had to re-do after a second look.  Note that while I've found bolts installed backwards on occasion and think in most cases it probably doesn't matter, there are definitely places where clearance of bolt head vs. nut is an issue.
• Don't get too carried away with paint quality on the walking beams & retract tubes - it's extraordinarily difficult to reinstall these without a nick or scrape here and there.
• Take pictures of the squat switch installation before disassembly, as re-installation isn't as obvious as you might think, and the parts manual isn't much help.
• If you have a 76-ish M20F, remember that some of the assemblies in the airplane are actually found in the M20J parts manual.

Hope this thread is helpful to anyone who takes on a similar project.

[Stephen]

Great writeup Vance, thanks. I have to do this after a few other issues are cleared up and it will be quite helpful.

[Stephen]

On 2/17/2018 at 11:06 AM, N201MKTurbo said:

I've done exactly that, I wouldn't recommend it. It is just plane dangerous. I have the tool now (well it is somewhere) and it only takes a few minuets to get the bolt out.

I just took the nose truss out and used a standard harbor freight press