Flap Pump Questions

[N201MKTurbo]

It will bleed out faster at high altitude. Take her up to 14000, slow down, and cycle them about a hundred times, or until they work right.

[carusoam]

On it's best days...

The first pump shows no movement of the flap.  Next Three pumps, flaps move evenly.  The last pump moves 1/4 (?) of the way.

From my M20C experience,

-a-

[DXB]

After a million pumps to get the air out, mine actually moves well with all 4 pumps, and requires exactly 4 to be at full.

[JaredDavis]

Ross' 12 step program has the first step as backing out the set screw. We skipped that step.  Any benefit to backing out the set screw before we start the marathon flap handle flapping sessions?

Prior to the leak the flaps were perfect. Every stroke moved the flaps.

The 3 stratoflex hoses replaced were dated December 7, 1964. They were stiff but still functional.  The flap cylinder o-ring was worn flat where it made contact with the cylinder wall. It was the source of the leak.

Hints on the rebuild kit:  Soak the leather washers for 10 minutes in 5606.  Use fuel lube (EZ Turn) on the cylinder threads to facilitate installation of the piston with new leather/o-ring.

 

[qualleyiv]

I've had the "opportunity" to do this process twice now and I wanted to add my little bit of Blackmagic to the whole bleeding scenario in case it might help anyone. I did the 12 step program and it worked--sort of--got a little bit of movement but never got it to where it was supposed to be so I added a couple of steps that took only a few minutes but worked 100% the first time. That's certainly not to say that the 12-step program is wrong or won't work, but I just had better luck adding basically one additional step (it doesn't look like it from the description, but it's basically just one extra step). Here are my additions:

1. After rebuilding the pump, I made sure to completely fill the pump cylinder with fluid before closing it up (hint: use the hose from your pressure pot for a nice clean way to fill the cylinder). Personally I think this is THE most important step however you do it.
2. Reinstall pump but only hook up the line coming from the fluid reservoir.
3. Connect the pressure pot to the outlet side of the pump (this is easy since it's the same fitting as the T fitting that you would normally be using anyways) and reverse bleed as in the original 12 step program. Also, now is a good time to verify that everything is working which you can do prior to bleeding by giving the pump handle a short pump (beware, it's probably going to shoot fluid everywhere--worth the risk IMHO because at least you can verify the pump is working).
4. Cap the outlet of the pump using the cap that would normally be blocking the T-fitting (the same plug you would remove to do the regular process) and connect the pressure pot to the normal location. This will allow you to bleed the short section of hose from the pump to the T-fitting. Pump fluid until it's coming out that hose.
5. While still having a little bit of pressure on the line, hook it back up to the outlet of the pump (will be messy--but so is this entire job).
6. Now disconnect the pressure pot and replace the cap on the T-fitting.

You should now have a system that functions as intended.

 

[Andy95W]

4 hours ago, qualleyiv said:

 

1. After rebuilding the pump, I made sure to completely fill the pump cylinder with fluid before closing it up. Personally I think this is THE most important step however you do it.

 

⬆️⬆️⬆️  +1

Without priming the pump per the above, you’ll drive yourself nuts trying to get it to start pumping fluid.  After that, it’s easy and straightforward. 

[Kesk]

Necroposting but...does anyone have a part number for the AN fitting that screws into the reservoir? We use these at work but I don't know for personal use. I'll report back if I find out from the parts clerk.

I'm also wondering if the ATS brake pressure pot will connect to the bleeder valve on the HE-626. That might have to be found out the hard way.

Edited February 19, 2024 by Kesk

[Shadrach]

3 hours ago, Kesk said:

Necroposting but...does anyone have a part number for the AN fitting that screws into the reservoir? We use these at work but I don't know for personal use. I'll report back if I find out from the parts clerk.

I'm also wondering if the ATS brake pressure pot will connect to the bleeder valve on the HE-626. That might have to be found out the hard way.

Something else that has been helpful to me is a hand vacuum (Mighty Vac) to help evacuate any remaining air from the system.

[Nathaniel Reece]

I have a M20E with the HE-626 actyator pump and it leaks hydraulic fluid randomly. With the belly skin off I cannot make it leak. I worked the flaps several times with no leaks. Then I take the airplane out for a flight and leave it over night and like magic a small puddle of hydraulic fluid appears on the floor. Does anyone have an idea what is going on here. I know its coming from the area of the flap actuator pump.

[Nathaniel Reece]

I have a M20E with the HE-626 actyator pump and it leaks hydraulic fluid randomly. With the belly skin off I cannot make it leak. I worked the flaps several times with no leaks. Then I take the airplane out for a flight and leave it over night and like magic a small puddle of hydraulic fluid appears on the floor. Does anyone have an idea what is going on here. I know its coming from the area of the flap actuator pump.

[Ragsf15e]

5 hours ago, Nathaniel Reece said:

I have a M20E with the HE-626 actyator pump and it leaks hydraulic fluid randomly. With the belly skin off I cannot make it leak. I worked the flaps several times with no leaks. Then I take the airplane out for a flight and leave it over night and like magic a small puddle of hydraulic fluid appears on the floor. Does anyone have an idea what is going on here. I know its coming from the area of the flap actuator pump.

Same fluid reservoir for your brakes and the parking brake valve (although that generally drips right onto the pilots feet).  Are you sure it’s the flaps?

@Shadrach

[PT20J]

Maybe it is the pressure caused by air load on the flaps. Try putting the flaps down on the ground and pulling up on them to simulate the air load and see if that makes it leak.

[Shadrach]

11 hours ago, Nathaniel Reece said:

I have a M20E with the HE-626 actyator pump and it leaks hydraulic fluid randomly. With the belly skin off I cannot make it leak. I worked the flaps several times with no leaks. Then I take the airplane out for a flight and leave it over night and like magic a small puddle of hydraulic fluid appears on the floor. Does anyone have an idea what is going on here. I know its coming from the area of the flap actuator pump.

Is it the actuator (mounted to the flaps and stub spar) or the pump (forward of the main spar and connected to cockpit pump handle)?

How big is the leak? Have you added fluid to the reservoir. Random leaks rarely occur but when they do it is usually caused by a contaminant temporarily compromising a seal. Fluid then leaks past the seal into the back side of the piston and out the cylinder vent hole. 

Have you physically removed the belly panels and inspected the system while actuating it? There’s only a handful of of potential leak points.

[Barneyw]

Hi All

This is not the way I wanted to start out on the Mooney Space threads and did have an elaborate title for my entrance but I find myself typing a post seeking help on the topic at hand.

I recently purchased a fully restored 1967 M20F with a J screen, Johnson Bar gear and accompanying flap hydraulic system and was going to take it for a flight today only to be greeted with this mess. See photos. One of the photos shows a drip forming at the join of belly panel 1 and 2

A  few questions

1. The AMM shows that the reservoir is located on the firewall yet the previous owner was indicating to me that the reservoir is on top of the left panel that runs along the nose gear door ie in front of belly panel 1. Is this correct?

2. When I asked the previous owner about the colour of the hydraulic/brake fluid he said "red" which at the time surprised me because I didn't think at the time GA aircraft used this type of fluid. Something that was even more of a surprise was, when asked what type of fluid it was he stated it was "automatic transmission fluid". Is this right?

At the time I did not have any tools available to remove all that I needed to remove but managed to remove the first belly panel to reveal that the leak is indeed coming from somewhere forward of this panel on the LHS of the aircraft.

More concerning is not so much what is in the AMM but what's not in the AMM eg procedure for topping up the reservoir and, moreover, the type of fluid used in the system. Some guidance please as I may have missed something.

Just to provide a bit of context here i have over 50 years in aviation in one form or another and with respect to hyd fluid my recollection is that GA hyd fluid is not red - the red stuff being H515 (a NATO. code I think) - so I was thrown by seeing the red fluid on the ground and disbelieving that it had come from the aircraft - there are a couple of reasons for that which I won't get into.

One last point, my last flight was about 30 minutes of circuits I put the aircraft in the hangar and I am usually there for a good thirty minutes after that. The flaps were up and the aircraft is chocked with the park brake off with no leaks evident. My point is that nothing in the system was pressurised so if someone can comment on this that would be great. Furthermore, there is no evidence that this leaked at all during flight

So after that rather lengthy intro to the Mooney Space - HELP!

Thanks in advance

BW

 

   

Edited April 27, 2024 by Barneyw

[carusoam]

Welcome aboard Barney!

Brake system on the M20F is quite simple…

and auto trans fluid would not be a proper liquid…

Brake lines and flap lines all get to and from the same place…

the return hoses get aged, crack , and leak…. 
 

sooo… start the research on what it still has for hoses…

expect pulling a belly panel off to get a good look…

they probably can’t be left from 1967…  but if they got changed once, they might be ready for a second set…

if the second stem has been OH’d.. you will be looking for a leak that needs to be tightened… follow the red trail… lots of clean up behind the belly panels

There is a newish modern brake fluid that is all the rage… fully miscible with the older standard…  not trans fluid. 

PP thoughts only,

-a-

[47U]

27 minutes ago, Barneyw said:

A  few questions

Welcome Barneyw…

1.  Being you have a J windscreen, access to your hydraulic reservoir maybe be impacted.  The reservoir is (was?) on the top-left firewall, cockpit side.  Depending on your J windscreen STC, there may be small triangular access panels on each side of where the avionics access panels were in front of the windscreen.  Some sloped windscreen conversions provided for hydraulic reservoir plumbing to the engine side of the firewall so that the reservoir could be serviced. 

2.  Red hydraulic fluid is MIL-H-5606, which can be replaced by a synthetic (I forget the spec).

If you’ve pulled the first belly panel aft of the nose gear wheel well and the leak appears to be forward and on the aircraft left side, that sounds like it may be coming from the brake system.  Both left and right brake master cylinders are underneath the exhaust cavity panel outboard of the left nose gear door.  

Please let us know what you find out… good luck!

[carusoam]

16 minutes ago, 47U said:

Welcome Barneyw…

1.  Being you have a J windscreen, access to your hydraulic reservoir maybe be impacted.  The reservoir is (was?) on the top-left firewall, cockpit side.  Depending on your J windscreen STC, there may be small triangular access panels on each side of where the avionics access panels were in front of the windscreen.  Some sloped windscreen conversions provided for hydraulic reservoir plumbing to the engine side of the firewall so that the reservoir could be serviced. 

2.  Red hydraulic fluid is MIL-H-5606, which can be replaced by a synthetic (I forget the spec).

If you’ve pulled the first belly panel aft of the nose gear wheel well and the leak appears to be forward and on the aircraft left side, that sounds like it may be coming from the brake system.  Both left and right brake master cylinders are underneath the exhaust cavity panel outboard of the left nose gear door.  

Please let us know what you find out… good luck!

Nice point 47U!

Talk to the person that tried to fill the reservoir…

without access from above, this might just be a big spill…. 

they make really nice snake cameras to look around…

Best regards,

-a-

[Shadrach]

Hi Barney,

The specified Fluid is 5606 and is indeed red. The synthetic replacement, Royco 782 is also red.  Hopefully there is some provision for accessing your reservoir which was/is mounted on the cabin side of the firewall on the pilot's side. Indeed the fluid type and bleeding procedure is in the MM which can be downloaded here. Section VI details the flap system and section II details lubricants and fluids.  You should also have an Illustrated parts manual which can be downloaded here 

That is quite a leak. Fist things first, remove the panels and track down the leak. There is a lot of information on Mooneyspace about this system. Use Google rather than the sight search tool as in "Mooneyspace Hydraulic Flaps".  Happy to help you get it squared away on the reinstallation. For now, you have your work cut out...

[Ragsf15e]

9 hours ago, Barneyw said:

Hi All

This is not the way I wanted to start out on the Mooney Space threads and did have an elaborate title for my entrance but I find myself typing a post seeking help on the topic at hand.

I recently purchased a fully restored 1967 M20F with a J screen, Johnson Bar gear and accompanying flap hydraulic system and was going to take it for a flight today only to be greeted with this mess. See photos. One of the photos shows a drip forming at the join of belly panel 1 and 2

A  few questions

1. The AMM shows that the reservoir is located on the firewall yet the previous owner was indicating to me that the reservoir is on top of the left panel that runs along the nose gear door ie in front of belly panel 1. Is this correct?

2. When I asked the previous owner about the colour of the hydraulic/brake fluid he said "red" which at the time surprised me because I didn't think at the time GA aircraft used this type of fluid. Something that was even more of a surprise was, when asked what type of fluid it was he stated it was "automatic transmission fluid". Is this right?

At the time I did not have any tools available to remove all that I needed to remove but managed to remove the first belly panel to reveal that the leak is indeed coming from somewhere forward of this panel on the LHS of the aircraft.

More concerning is not so much what is in the AMM but what's not in the AMM eg procedure for topping up the reservoir and, moreover, the type of fluid used in the system. Some guidance please as I may have missed something.

Just to provide a bit of context here i have over 50 years in aviation in one form or another and with respect to hyd fluid my recollection is that GA hyd fluid is not red - the red stuff being H515 (a NATO. code I think) - so I was thrown by seeing the red fluid on the ground and disbelieving that it had come from the aircraft - there are a couple of reasons for that which I won't get into.

One last point, my last flight was about 30 minutes of circuits I put the aircraft in the hangar and I am usually there for a good thirty minutes after that. The flaps were up and the aircraft is chocked with the park brake off with no leaks evident. My point is that nothing in the system was pressurised so if someone can comment on this that would be great. Furthermore, there is no evidence that this leaked at all during flight

So after that rather lengthy intro to the Mooney Space - HELP!

Thanks in advance

BW

 

   

My F did that to me once. Only time in 10 years that she stranded me, and it only ended up being one day!  Mine was indeed an O ring in one of the master cylinders for the brakes just above the left exhaust cavity (there’s no exhaust there).  Relatively easy fix for the mechanic I found who helped me.

I also have an F with the J windscreen.  My hydraulic reservoir is still on the upper firewall inside the cockpit directly in front of the pilot.  If you contort and lay under the pilot side instrument panel, you can just see it.  Taking out the seat helps.  Luckily, that shouldn’t be necessary!  Someone put a fill tube and breather tube with valves through the firewall into the engine compartment directly in front of the pilot. Easy to access there.  No guarantee yours is the same however.

[PT20J]

11 hours ago, Barneyw said:

When I asked the previous owner about the colour of the hydraulic/brake fluid he said "red" which at the time surprised me because I didn't think at the time GA aircraft used this type of fluid. Something that was even more of a surprise was, when asked what type of fluid it was he stated it was "automatic transmission fluid". Is this right?

No, it's not right.

Aircraft 5606 hydraulic fluid is a mineral oil dyed red. Automatic transmission fluid (ATF) may be mineral oil dyed red, BUT there are several kinds of ATF and the newer ones have additive packages and some use a synthetic base stock rather than mineral oil. There will also be viscosity differences between 5606 and ATF.

If this were my airplane, I would find out if the previous owner was using ATF in the hydraulic system. The problem is that there are a lot of o-rings in the system and o-rings are available in several materials and not all are compatible with all fluids. If a fluid was used that is not compatible with the o-rings, it can cause them to deteriorate and leak. If this is the case -- and I don't know if it is -- you might be faced with replacing all the o-rings in the system to prevent leaks and failures. That's why I'd want to find out what the airplane was serviced with.

[Barneyw]

First of all a big note of thanks for all the rapid replies and inputs to my problem. Here are my responses.

1. It was indeed the LH brake master cylinder. See the photo.

2. It dumped the whole reservoir overboard - bone dry. Such a lot of mess for a small reservoir.

3. I do have the two triangular shaped panels and the reservoir is mounted still in its original position in the cockpit.

4. I get the point about the O-rings and I reconfirmed that a synthetic ATF was used, to my shock to be honest. Apparently it is common practice mainly to save cost although that's debatable now.

5. Thank you for the links to the new AMM and IPB - very useful. My manuals have a 197x handle.

The question is now do I replace both cylinder's O-rings while it's apart and possibly the flap valve and flush the system and replace the oil to a more conventional one or continue with the ATF. I'm leading towards convention.

This is a job I should be able to do myself, under supervision, and get the mechanic with the gear to bleed the system and I should be on my way. 

Thanks for the welcome and excellent info.

Next time I post it will be more about me and the aircraft which was to be titled "I bought a Mooney, now what!?"

Cheers

BW  

 

[PT20J]

1 hour ago, Barneyw said:

I get the point about the O-rings and I reconfirmed that a synthetic ATF was used, to my shock to be honest. Apparently it is common practice mainly to save cost although that's debatable now.

It is not common practice to use non-aircraft materials in an airplane. And if the previous owner did this, I would be concerned about what other shortcuts may have been taken. This doesn’t even save money: NAPA Auto Parts sells Dexron III for $11.33/qt. Aircraft Spruce sells MIL-H-5606A for $12.50/qt.

[47U]

1 hour ago, Barneyw said:

The question is now do I replace both cylinder's O-rings while it's apart and possibly the flap valve and flush the system and replace the oil to a more conventional one or continue with the ATF. I'm leading towards convention.

 

Schematics for all the components are in the mx manual.  You might also consider the o-rings in the flap actuator, parking brake valve, and perhaps most important, brake calipers.  It’d be a bummer to land and discover there’s no brakes.  And the hoses?  Particularly the -303 supply hose to the flap pump.  It’s a low-pressure hose and has no wire reinforcement.

I feel for you that this is your introduction to Mooney ownership.  But once sorted out, you’ll have great confidence in your airplane going forward.

[Shadrach]

2 hours ago, Barneyw said:

First of all a big note of thanks for all the rapid replies and inputs to my problem. Here are my responses.

1. It was indeed the LH brake master cylinder. See the photo.

2. It dumped the whole reservoir overboard - bone dry. Such a lot of mess for a small reservoir.

3. I do have the two triangular shaped panels and the reservoir is mounted still in its original position in the cockpit.

4. I get the point about the O-rings and I reconfirmed that a synthetic ATF was used, to my shock to be honest. Apparently it is common practice mainly to save cost although that's debatable now.

5. Thank you for the links to the new AMM and IPB - very useful. My manuals have a 197x handle.

The question is now do I replace both cylinder's O-rings while it's apart and possibly the flap valve and flush the system and replace the oil to a more conventional one or continue with the ATF. I'm leading towards convention.

This is a job I should be able to do myself, under supervision, and get the mechanic with the gear to bleed the system and I should be on my way. 

Thanks for the welcome and excellent info.

Next time I post it will be more about me and the aircraft which was to be titled "I bought a Mooney, now what!?"

Cheers

BW  

 

I would do both of the brake cylinders, the parking break and consider doing the flap pump and actuator given the system will be drained (correct course of action given that it’s been filled with ATF).
The cost of the O-ring kits for the brake cylinders and flap components is trivial. 
 

2 X Brake Cylinder seal kit - $7.48

https://lasar.com/seal-kits/brake-master-cylinder-seal-kit-drawing-for-paramount-b47g-kit090-brake-master-cyl-b47g-paramount-seal-kit

1 X Scott 4200A seal kit $8.50
https://lasar.com/seals-gaskets/parking-brake-valve-seal-kit-scott-4200-a1

1 X Flap pump seal kit - $37.54

https://lasar.com/seal-kits/flap-pump-valve-assembly-seal-kit-drawing-kit098-001-flap-pump-seal-kit-hydraulic

1 X Flap Actuator seal kit - $39

https://lasar.com/seal-kits/flap-cylinder-repair-seal-kit-drawing-flap-cylinder-seal-kit-hydraulic
 

Since you’re paying the shipping anyway, I would buy a few seal kits for the Shaw fuel caps as well. I always keep these in stock.

2 X Shaw fuel cap seal kit -13.05

Should be <$150 for everything with shipping.

[Shadrach]

 

2 hours ago, Barneyw said:

4. I get the point about the O-rings and I reconfirmed that a synthetic ATF was used, to my shock to be honest. Apparently it is common practice mainly to save cost although that's debatable now.

5. Thank you for the links to the new AMM and IPB - very useful. My manuals have a 197x handle.

The question is now do I replace both cylinder's O-rings while it's apart and possibly the flap valve and flush the system and replace the oil to a more conventional one or continue with the ATF. I'm leading towards convention.

 

I don’t know the previous owner but I do know the in 20+ years of vintage Mooney flying and maintenance (13 of which I have been on this board), I have never heard of anyone using ATF as hydraulic fluid in a Mooney. I’ve seen it used interchangeably with PS fluid in cars, but that’s it. 
There is nothing conventional nor commonplace about using non approved fluids. No competent maintenance professional would recommend such a thing.

When you refill with approved. Luis, I would recommend using Synthetic Royco 782.