Mooney M-20F Hydraulic Flaps (incl flap pump and actuator)

Mooney "Johnson bar" manual gear in action: • Mooney manual gear Joh...
Early Mooney models had manually retractable landing gear and hydraulic flaps. This video shows extension and retraction of the flaps in my Mooney M-20F, and shows what the flap pump looks like and how it works.

[@crazypilot4017]

Nice 👍. Just bought a ‘68 Mooney M20C. In the process of restoring and upgrading it now.

[@fsodn]

Very cool! Good luck getting it back in the air!

[@glennbukac7533]

I have a crazy situation after disassembling my hydraulic pump. Everything works perfectly 4 1/2 almost 5 pumps. Nobley down works great except the Select Lever or valve lever operates opposites of yours.

[@fsodn]

You didn't say where you and the airplane reside, but in the US, and I imagine any country under ICAO, working on a pump, assembling a pump, installing it, connecting it, are all things that ONLY AN A&P (or equivalent) ARE LEGALLY ALLOWED TO DO. Flaps aren't a primary control, but if they malfunction (if they extend and won't retract, for instance, or if they retract a bunch unexpectedly) that can have fatal consequences. Whoever rebuilt the pump has the legal responsibility to do so correctly and only turn it over to a non-mechanic when it works the way the controls are labelled. If it doesn't work that way, bring it back to whoever did the the work. I don't know what else to tell you.

[@glennbukac7533]

@@fsodn I got it figured out. the little level that opens the valve to bleed pressure out has a small range of motion where it bleeds out the pressure. I had the cable installed and adjusted so I was on the wrong side of the cam. adjusted cable and lever and all is good. great video By the way I am an A&P and IA plane is located at KLOT Lewis univ airport Romeoville Illinois USA

[@fsodn]

Ah, excellent. Ok; sorry; I didn't know the context. My apologies; I get lots of questions sounding like non-A&P owners are trying to do something sly in order to not pay a mechanic. Cool; glad it's working now!

[@Aviator-CFRN]

Mine has been a nightmare -my mechanic cannot fix it correctly and sent it out to Maxwell and it still leaked. Now its at Lasar being rebuilt -hopefully this will be the needed fix! Thanks for the informative video.

[@fsodn]

I haven't had any problems with mine leaking. Those are the places that I'd send it if I had problems. I did have a problem with mine. I ended up buying one on ebay, having my mechanic refurbish the one I'd bought, and then he installed it in the plane.

[@jeromes5141]

I'm a new owner of a 65 M20C. Yesterday I went up to check on the attitude indicator which was all over the place last flight for about 3 minutes before it came back. It was wobbling for about 10 minutes before staying still, then it started working normally. When I was ready to land, I lowered the flap and that actuator switch felt free. When I pumped the lever, it also felt free. Flaps went down a a little before returning to the up position. Hoping it's not an expensive fix. Nice video.

[@fsodn]

I feel your pain. I've only owned one airplane, but I've gathered that the first while of owning any plane(and the first couple of annuals) are always an exercise figuring what what former owners have done for failed to do. I have no thoughts about the AI, other than if I were you I'd start shopping for somewhere to rebuild it. I'm not a mechanic, but I've done a lot of adjusting and checking on Mooney flap pumps (with mechanics). Let me know if you'd like my thoughts on this. The good news is you can probably do a lot of the diagnosing on the ground.

[@jeromes5141]

@@fsodn the cable broke. Saw it when I made a gokd inspection of the area today. Mechanic going to hunt the replacement.

[@fsodn]

Fantastic that you found the problem! I hope it's fixed. Good luck!

[@FreeRoofingQuotes]

Assuming I’m pumping my flaps and they don’t go down what likely needs to be done? They worked just fine until today

[@fsodn]

So you own and/or fly a Mooney with hydraulic flaps? And up until this point, they have operated as I show here (select down, pump and stay down, select up, retract slowly)? And now, no matter the selection, you pump the handle and no movement? If I understand your position, if I were in that position, here is what I would do to try to debug: DO NOT FLY THE PLANE (or taxi it). If the flaps are having problems, the brakes might be too, and that can make very a very messy or expensive day. Check the hydraulic fluid reservoir. With the flaps retracted it should be close to full up to the filler opening. If it's way down, you're going to have to find the source of the leak. That's going to take some detective work. Also check the brakes to make sure they've firm. If fluid is low, now you'll need to get a mechanic. They'll have to fix the leak. If there's plenty of fluid but this is still happening, the mechanic will then check to see if the cockpit switch is disconnected from the cable, or if the rod has become disconnected from the flap mechanism. If there's no fluid leaking, and everything is hooked up, then perhaps something has gone wrong inside the pump.

[@travelveteran]

When I pump mine. My flaps don’t move. Is it possibly just a quick fix to replace the hydraulic fluid?

[@fsodn]

Ok, this sounds like the sort of question that's best debugged with an A&P and not by strangers on the internet. If you have a Mooney with hydraulic flaps, the same hydraulic system runs the brakes, and not having brakes is a potentially unsafe situation. So good luck, but get some real help.

[@matthewkruger8417]

Hi I just bought one of theses birds...Have you bled the system before and how do you fill the reservoir....I must have air in the system..... Mine is not working like as you have shown. And it seams as though there is air in the system.....Also the indicator does not go to full even when I have the flaps all the way down..... Need Help!

[@fsodn]

Hi Matthew! Welcome to the Mooney club! I have never bled the system, no. I've had mechanics do that. The hydraulic system isn't very well-designed from that point of view. The only way I've seen it done has been with a pressure pot power bleeder, bleeding from the bottom (brakes) up. "Mine is not working like as you have shown" What does yours do? How does it act? Did the seller demonstrate the flaps before you bought it? How to fill the hydraulic reservoir: I would definitely make sure the reservoir is full. When my reservoir got low, the brakes acted funny. They would work with the pedals, but they wouldn't hold with the parking brake set. If something is weird, that's the first thing that I'd try. Get a container of proper aviation hydraulic fluid from Aircraft Spruce somewhere. It's red. You'll need a funnel with a very narrow neck. I bought a really tiny silicone funnel in a kitchen store that works really well. As to how to *get* to the hydraulic reservoir: If it's like mine, you'll have to take off the upper cowlings. If you've never done that, I suggest you get a mechanic or a pilot friend and have them show you how to do this. It's not hard, and owner/pilots are allowed to remove and re-install cowlings, but there are some tricks, and doing it wrong could be very dangerous. Have someone show you if you've never done it. I wouldn't worry about the indicator. Look at 2:57 in my video. That's with flaps pumped all the way down, and my indicator doesn't go to the bottom either. I have the indicator set so that all the way up is at the "up" mark, and then flaps at "takeoff" mark is about what it should be. It should be at takeoff position at roughly two pumps from up. Let me know if there's anything else I can do. What model and year do you have?

[@travelveteran]

It was working, brought it in for annual, now it’s not working after I got it back from the annual. It barely worked and I got them down after like 20 pumps. Now 100 pumps and they don’t move whatsoever. Feels like there’s no fluid in there.

[@travelveteran]

Mine is a 1965 m20C mark 21

[@mikesax]

Great video... thanks WD40 should never be used on airplanes... it is very corrosive... I dislike that product

[@fsodn]

Yes, it was formulated to be a "Water Dispersant" for rockets, thus the "WD". I agree with you that it is greatly overused as a general-purpose lubricant (which it definitely isn't). In some cases, it does have decent properties for freeing up movement as long as the moving thing isn't particularly exposed to outside air and dust, which will stick to the wd-40 over time and gum it up (over months and years). I've heard people say that it's "corrosive". Is it really? I don't think it is to ferrous metals; I've certainly known people (myself included) to de-rust and free up steel tools that have gotten a bit of rust on them. Is it actually reactive with Aluminum? Bare Aluminum, painted Aluminum? I don't know. Do you have a reference for that?

[@mikesax]

@fsodn thanks. Did not know the history. All I know is that every moving metal part I've used it on, has seized badly. And was a nightmare to unseize. Now I use Fluid Film ... and I swear by it love it .. has never let me down. Cheers

[@fsodn]

Yes, I completely agree. WD-40, while it sometimes superficially works as a short-term lubricant, often ends up gumming things up and making moving worse in the long term. Yes, there are definitely other real lubricants that do not do this, and that are appropriate to use on aircraft. I think "tri-flow" is generally recommended for Mooney control surface hinges, for instance. I haven't heard of "fluid film" but I have no reason to doubt it. You absolutely should never, ever use WD-40 on a cable in a sheath. It will collect dust, become very sticky, and render the cable unusable.