Landing Gear Issue, 1967 T337B

[cessnadriver]

Ohio skymaster.
You might check the micro switches. There is one at the bottom of the hydraulic power pack, and the three gear uplock switches. If any are not making good contact this will cause an intermittent lights.
Hope this helps.
Regards, BILLS

[wslade2]

Granted, poorly operating micro switches can cause indicator light issues. You are a B model with engine driven hydraulic pump. you mentioned the gear handle not returning to the neutral position on its own and you manually moved it to center. Worrisome for a low pressure situation. The causes are numerous. So many times , stung by the basics. Check your fluid level first.

[hharney]

All good comments and warranted likely causes. But don't get hung up on the obvious, it can be a microswitch but it can also just be a bad connection to the microswitch. This system is a daisy chain around the airplane that connects from point to point so it could be any connection along that chain. It is sometimes hard to tell if the connector or connection is bad so take some time and trouble shoot each point. It should be on jacks to do this as you will want to swing the gear to detect the fault. Remember a lot of issues only happen in the air because of vortexes from flying so they may not be duplicated on the jacks.

[Jhogan0101]

I have a 337B. During runup i always push the gear handle DOWN. It will usually pop back up to neutral in cold weather about 7 secs, 4-5 secs during warmer weather.

[GAdams]

To state the obvious even more. Check hydraulic fluid level and be sure the system is adequately purged of air. I was surprised how many cycles we had to do on the jacks to get the air out of the system. And how much more fluid it took after each purging attempt.

[Jhogan0101]

Attached is another way from service manual to purge air from system without placing on jacks.

5-128. BLEEDING TIME-DELAY VALVE.
The
Time-delay valve in the Power Pack may be purged of
air by operating the engine-driven pump, or the
Hydro Test may be used.
2.
Make sure reservoir is full.
b
Start engine and let run at 1000 rpm, or connegt
Hydro Test in accordance with paragraph 5-125
Place landing gear handle in the down position
and hold for approximately one minute, while turning
the master switch OFF
until doors open,
then ON un-
til doors close.
d.
Repeat step "c" four times, waiting one minute
between steps.
e.
Check that time-delay operates properly by mov-
ing gear handle sharply to the down position and re-
cording time as handle returns to neutral.
NOTE
The time delay between closing of the landing
gear doors and releasing the landing gear
handle to neutral should be between 3 and 9
seconds at room temperature. Colder temper-
atures will cause a longer delay.
i.
Shut down engine, or disconnect Hydro Test in
accordance with paragraph 5-126.

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