1981 Cessna T210N landing gear

jerrykjb

My landing gear has worked flawless up to yesterday. After taking off and putting gear up I noticed the hydraulic gear pump would run for a second about every 15-20 seconds. Pulled the breaker and flew to my destination. Pushed in the breaker and put the gear down. Worked great but now the pump runs continuously. Checked the fluid level and it is full. Looked for any leaks anywhere and everything is dry. Did the same procedure flying back home. While in the air I cycled the gear several times and it goes up and down in less than 10 secs. I’m thinking the pump is good but pressure Relief valve or the pressure switch is bad. Has anyone had this happen to them?

Scott Sherer

Have you had your A&P look at it? What does your service manual say in the landing gear maintenance section?

jerrykjb

My A&P is a month out and the other A&P I have used some is over 2 months out. I was hoping someone may have had this situation to maybe get what was their failure.

The service manual says that pressure relief and the pressure switch are the possible problem.

Scott Sherer

OK, sounds like progress. Speaking of delays, my plane went in the shop okay and on-time. Unfortunately, it was four months before it came out. Oh well, you have my empathy. :)

Paul New

Jerry,

The pressure switch seems like the starting point. Unfortunately, this will best be addressed with the plane on jacks. The wiring diagram in the service manual is very simple and should be easy to trace. From the 5 amp CB power goes through the squat switch then through the pressure switch to the pump motor. There are no uplocks so either the pressure is dropping causing the pressure switch to stay engaged or the switch needs to be adjusted to the correct pressure.

Does this issue also occur when you put the gear down? I inferred from your description that it doesn't.

jerrykjb

The pump keeps running whether the gear is up or down.

jerrykjb

Who rebuilds the power packs?

Scott Sherer

Have you checked our website? Here's a link: https://cessnaowner.org/business-directory/directory/landing-gear-overhaul-repair/

Paul New

Jerry,

This is not likely a Power Pack failure. Some simple troubleshooting with a voltmeter will easily isolate the offending component - most likely the pressure switch. Changing the power pack is a significant job with MANY oppurtunities to cause more problems than you started with.

jerrykjb

This ended up way different than I expected. I found even with the contactor coil disconnected the pump kept running. The contacts must be welded together. After hitting it a fewtimes it shut off and started working normally.

Thanks for everyones input, gave me a starting place to figure this out. I will just have to replace the solenoid and be back in the air after I get my A&P to inspect and sign off on it.

Thanks again, Jerry

Just a note, I'm grateful it wasn't the pressure switch at $5k, a little pricey.

Rdiaz1

Jerry, where is the contactor coil (solenoid) located? By the power pack?

jerrykjb

The solenoid is about 3” aft and about the same height as the top of the power pack motor. So basically right by the power pack. A little hard to replace but what part in an airplane isn’t hard to replace. To disassemble the center console and replace the solenoid took me a little over two hours and one skinned knuckle.