No Green Light on gear, after sitting for a week

[Skymaster337B]

Has anyone ever noticed an unsafe gear indication during the cockpit preflight? But once started and push the handle down, the green light comes on and will stay one for the rest of the time. But then after the flight, let the airplane sit until the following weekend, and the green light no longer comes on when you turn on the batttery switch. But once again, crank it up and push the gear handle down and everything appears normal.

[Pete Somers]

You need to open the gear doors and operate each downlock microswitch to see which one is either out of alignment or needs replacng.

Pete

[Skymaster337B]

Took the nose gear actuator/downlock out. It had a broken pin the connects the two halves of the downlock hook. However, the really big problem was the servo's interal locking mechanisim was very weak -- only a few PSI pull to make the servo extend.

So I'm overhauling the entire assembly.

[skymstr02]

There is a Cessna service bulletin to replace that plastic son of a gun with one that has a metal pin to replace the plastic pin. The service bulletin only has the 210 as effective aircraft, but it is the same part number. If you order the original part number, Cessna's parts computer will replace it with the new part.

The bulletin is about 20 years old.

[Skymaster337B]

Any suggestion on how to unscrew the head of the servo off of the tube? The book says to use a strap wrench. I tried that and I broke the strap wrench in the process. I've used a vise, tried hitting it, heating it, freezing it, but it still doesn't move. The nuts are loose, but the head of the servo will not loosen. Yes, the set screw is removed. The problem is, the servo tube has no place for a wrench to grab on since it's round.

I've also soaked it in WD-40. Should I try 3 in 1 too?

[skymstr02]

I had made two "V" blocks from some hard wood, and chucked it up in a vise. If the threads are dicked up from gauling, good luck.

[Skymaster337B]

Finally got it unscrewed. Had to use the biggest strap wrench I've ever seen, and it still took a very large man to bust it lose.

As it turns out, the spring on the bottom of the actuator was not as long as it should be -- too many compressions over the years. A new spring was only a few bucks. I highly recommend a new spring if you haven't had one in over 30 years. It's the only way the internal locking mechinism will work.

[Skymaster337B]

At least one thing I learned from this experience -- besides the fact that just because your nose gear works, doesn't mean something inside isn't broke (like the internal lock, or the plastic rod that connects the downlock hook). That is: if you ever want an easy way to drain your hydraulic reservior, just open up the nose gear actuator return line.

[Skymaster337B]

I Installed the actuator back into the airplane today. Not easy, unless you have 3 extra joins between your elbow and wrist. Doing it the way the book said DOES NOT WORK. The way I finally had to install it was: install the downlock hook by itself onto the strut. Then, screw the actuator piston into the downlock hook. Finally, install the actuator forward end into its slot.