Hydraulic Flap parts

[Huitt3106]

Does anybody have a line on the Teflon seals that are in the hydraulic flap pump? It’s part number HE1517.

 

Our mooney M20C is currently in annual and the flaps were leaking down. Apparently the Teflon seals are in poor condition and need to be replaced. The mechanic has tried staking them as mentioned in previous post and was unsuccessful. We’re now looking for either used parts or if anybody has had them made?

 

 

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[Mooney45]

I ordered rebuild kits from LASAR when I overhauled all my hydraulic systems. Some of them we a leather type material if I remember correctly, not sure what system that was though.

[Huitt3106]

Thank you but I’ve spoken with Lasar. Their rebuild kits for the flap hydraulics do not include any hard parts (ball, spring, Teflon seal, etc). I think you have to either find them used or have them made.


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[carusoam]

Welcome aboard 45....

Great first post...

The Teflon seals start out as perfect cylinders...

So if you can’t get them through your local MSC...

Making them shouldn’t be excessively hard...  key words - shouldn’t be...
 

Invite @Shadrach for flap pump insight... (Teflon seals)

Best regards,

-a-

[Nukemzzz]

You don’t stake the Teflon seats.  You stake the ball under the adjust screw. why do you think they are in bad shape?  

[Nukemzzz]

Check this post that made to explain how this system works and how to troubleshoot it. Hope this helps. 
 

https://mooneyspace.com/topic/33869-m20-hydraulic-pump-flap-diagram/page/4/

[Huitt3106]

You don’t stake the Teflon seats.  You stake the ball under the adjust screw. why do you think they are in bad shape?  

I’m going off information from the mechanic. It’s at a reputable MSC in annual right now. I don’t know exactly what is being seen but it sounds like the Teflon seals are in bad shape. Thanks!


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[Nukemzzz]

3 hours ago, Huitt3106 said:

I’m going off information from the mechanic. It’s at a reputable MSC in annual right now. I don’t know exactly what is being seen but it sounds like the Teflon seals are in bad shape. Thanks!


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I see. They should know. 

You might need to get new ones made at a machine shop. 

[rbridges]

John Breda made me some out of teflon using a lathe.  My annual is in 2 weeks at AGL.  I"ll let you know if they work.  LASAR told me the teflon seals have not been manufactured since the 70's.  Unless someone messed with yours, they should be immaculate.  My got damaged when the IA used a pick to remove them.  UGH.  He thought they were nylon, but the teflon is very soft and easily deformed with metal instruments.  

[Huitt3106]

6 minutes ago, rbridges said:

John Breda made me some out of teflon using a lathe.  My annual is in 2 weeks at AGL.  I"ll let you know if they work.  LASAR told me the teflon seals have not been manufactured since the 70's.  Unless someone messed with yours, they should be immaculate.  My got damaged when the IA used a pick to remove them.  UGH.  He thought they were nylon, but the teflon is very soft and easily deformed with metal instruments.  

Ours is currently in annual at AGL.  I'm not sure what happened to them, he just can't get them to seal as of yesterday.  He didn't happen to make you 2 more did he? Haha

[rbridges]

Just now, Huitt3106 said:

Ours is currently in annual at AGL.  I'm not sure what happened to them, he just can't get them to seal as of yesterday.  He didn't happen to make you 2 more did he? Haha

he actually did, of various sizes.  If you'll pay overnight shipping, I can send the package to AGL and let him try them out.  I can't guarantee if they'll work or not.  I won't be able to ship them until tomorrow since I'm at work.  I can send pics tonight if you want to see them first.

 

[Huitt3106]

he actually did, of various sizes.  If you'll pay overnight shipping, I can send the package to AGL and let him try them out.  I can't guarantee if they'll work or not.  I won't be able to ship them until tomorrow since I'm at work.  I can send pics tonight if you want to see them first.
 

Sent you a PM. Thanks!


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[Shadrach]

15 hours ago, Nukemzzz said:

You don’t stake the Teflon seats.  You stake the ball under the adjust screw. why do you think they are in bad shape?  

Indeed one may need to lightly stake the teflon seats as well. @rbridges went through this recently...

[Shadrach]

@Huitt3106

Looking at your photo, I am trying to discern how the lower ball valve has been assembled.

What is the outer ring that I have marked with the red arrow?  The ball should be the only thing in contact with the seat of the Teflon ring. In your picture it looks like the spring or some other piece of material is interfering.

 

[Huitt3106]

Just now, Shadrach said:

@Huitt3106

Looking at your photo, I am trying to discern how the lower ball valve has been assembled.

What is the outer ring that I have marked with the red arrow?  The ball should be the only thing in contact with the seat of the Teflon ring. In your picture it looks like the spring or some other piece of material is interfering.

 

I'm not at all sure what that is in the picture, could it just be residual flud that has fallent to the lowest point on the ball? This picture was sent by the A&P.

[Shadrach]

Just now, Huitt3106 said:

I'm not at all sure what that is in the picture, could it just be residual flud that has fallent to the lowest point on the ball? This picture was sent by the A&P.

Were the flaps leaking down before he tried to fix them?  It does not look like fluid. It looks like the ball is not in contact with the seat. 

[Huitt3106]

4 minutes ago, Shadrach said:

Were the flaps leaking down before he tried to fix them?  It does not look like fluid. It looks like the ball is not in contact with the seat. 

Yes, they were slowly leaking down. He said the teflon seals were in pretty bad shape and we've got a few headed his way to try and fix the problem. 

[Nukemzzz]

If the inlet Teflon seat leaks then it takes more strokes to pump the flaps down because some of the fluid is returning to the supply reservoir. Flaps won’t leak back up though. 

If the outlet Teflon sear leaks the handle in the cabin will lift by itself as the flaps try to leak back up because the pumping chamber is back filling from the actuator.  Unless the inlet is also leaking then the flaps won’t leak all the way back up.

The flaps leaking back up is the cable actuated pressure relief check ball on the aluminum seat leaking unless you have an external fluid leak or the handle in the cabin is raising by itself as well. 

Replacing the Teflon seals won’t hurt, but need to stake the aluminum seat or it will likely still leak back up. 

Not that you need this info as the MSC has this in their capable hands. Just trying to keep this info out there for others. 

[rbridges]

4 hours ago, Shadrach said:

Indeed one may need to lightly stake the teflon seats as well. @rbridges went through this recently...

It did help, but not 100%. Flaps hd position in the hangar, but move really slow under prop wash. 

[Shadrach]

18 hours ago, Nukemzzz said:

If the inlet Teflon seat leaks then it takes more strokes to pump the flaps down because some of the fluid is returning to the supply reservoir. Flaps won’t leak back up though. 

If the outlet Teflon sear leaks the handle in the cabin will lift by itself as the flaps try to leak back up because the pumping chamber is back filling from the actuator.  Unless the inlet is also leaking then the flaps won’t leak all the way back up.

The flaps leaking back up is the cable actuated pressure relief check ball on the aluminum seat leaking unless you have an external fluid leak or the handle in the cabin is raising by itself as well. 

Replacing the Teflon seals won’t hurt, but need to stake the aluminum seat or it will likely still leak back up. 

Not that you need this info as the MSC has this in their capable hands. Just trying to keep this info out there for others. 

If both of the teflon seats are leaking the flaps will indeed slowly leak back up. It's not as uncommon as you might think.

[M20F-1968]

I can make more of these if necessary.  

John Breda

[M20F-1968]

On 9/1/2020 at 10:06 AM, rbridges said:

John Breda made me some out of teflon using a lathe.  My annual is in 2 weeks at AGL.  I"ll let you know if they work.  LASAR told me the teflon seals have not been manufactured since the 70's.  Unless someone messed with yours, they should be immaculate.  My got damaged when the IA used a pick to remove them.  UGH.  He thought they were nylon, but the teflon is very soft and easily deformed with metal instruments.  

 

On 8/31/2020 at 6:11 PM, Huitt3106 said:

 

Does anybody have a line on the Teflon seals that are in the hydraulic flap pump? It’s part number HE1517.

 

Our mooney M20C is currently in annual and the flaps were leaking down. Apparently the Teflon seals are in poor condition and need to be replaced. The mechanic has tried staking them as mentioned in previous post and was unsuccessful. We’re now looking for either used parts or if anybody has had them made?

 

 

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I can make more of these if necessary.  Need a regular lathe and a watchmaker's lathe to finish the back side.

John Breda

cell:  617-877-0025

 

[rbridges]

Just now, M20F-1968 said:

 

I can make more of these if necessary.  Need a regular lathe and a watchmaker's lathe to finish the back side.

John Breda

cell:  617-877-0025

 

I sent them to AGL this morning.  I'll let you know if I learn anything.

[Nukemzzz]

21 hours ago, Shadrach said:

If both of the teflon seats are leaking the flaps will indeed slowly leak back up. It's not as uncommon as you might think.

Sure its possible.  But a single cause failure is more likely than a two cause failure.  The chance of rolling a 1 on a single dice throw is 1/6.  The chance of rolling snake eyes on a dual dice throw is 1/36.  The daily hazard rate for each of these 3 seats is probably closer to 1/10,000 so the chance of two failing on the same day is closer to 1/100 million which is getting closer to winning the lottery.  So the only feasible way I can see both of them failing to cause this issue is if the Inlet started leaking first and then you lost pumping efficiency but didn't have a noticeable problem, and the at some point later the outlet started leaking as well.   The chance of this?? no idea

Sorry, I'm a Product Reliability Leader with a background in statistics so I love this kinda stuff.  lol

[Shadrach]

On 9/3/2020 at 9:25 AM, Nukemzzz said:

Sure its possible.  But a single cause failure is more likely than a two cause failure.  The chance of rolling a 1 on a single dice throw is 1/6.  The chance of rolling snake eyes on a dual dice throw is 1/36.  The daily hazard rate for each of these 3 seats is probably closer to 1/10,000 so the chance of two failing on the same day is closer to 1/100 million which is getting closer to winning the lottery.  So the only feasible way I can see both of them failing to cause this issue is if the Inlet started leaking first and then you lost pumping efficiency but didn't have a noticeable problem, and the at some point later the outlet started leaking as well.   The chance of this?? no idea

Sorry, I'm a Product Reliability Leader with a background in statistics so I love this kinda stuff.  lol

I appreciate your experience and statistical analysis.  However, while applying that analysis to a a 50+ year old airframe that has been owned by multiple individuals and maintained by dozens is an interesting exercise, it's far from a vintage Mooney's operational reality. It assumes the chances of an event with a double failure of a properly functioning system.  What is more typical with 50 year old airplanes is that a human has attempted to "repair" the system and fails to ensure every thing is properly seated during reassemble.  This may only result in a single failure as part of the "repair". There are certainly owners flying around with flaps that stay down but are sucking air or pushing fluid two directions through an unseated valve...or are not properly bled...or have had incorrect hardware substituted or...etc...  They live with sub-optimal performance until a second point of failure. The system then goes from functioning sub optimally to not functioning at all.  This chain of events sometimes starts with an non-Mooney specific IA spotting a few drops of hydraulic fluid on the belly and prescribing a pump overhaul.  

I truly respect and appreciate your expertise in the field but applying it to vintage Mooneys is a bit like applying it to the Cuban taxi cab fleet.