Huitt3106 Posted September 3, 2020 Author Report Share Posted September 3, 2020 2 minutes ago, Shadrach said: I appreciate your experience and statistical analysis. However, 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 a 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 to ways 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. In this situation, from speaking with the IA, its most likely from a previous A&P that attempted a repair. It sounds like they're in rough shape and weren't properly repaired or replaced in the past (the flap "auto-retraction" is very slow so it probably wasn't noticed in the past). The double point of failure makes sense if the previous mechanic used a rough tool for removing them both and scarred them beyond proper function in the past (just a guess as I'm not looking at them myself). 1 Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted September 3, 2020 Report Share Posted September 3, 2020 FWIW Teflon will cold flow. If you set the damaged seal on a table with a ball in the seat and set a fairly heavy weight (5 lbs or so) on the ball, it would probably form a tight seal in a few days. You could verify using a microscope or a loup. Might not take that long. 1 2 Quote Link to comment Share on other sites More sharing options...
Shadrach Posted September 3, 2020 Report Share Posted September 3, 2020 (edited) 2 hours ago, N201MKTurbo said: FWIW Teflon will cold flow. If you set the damaged seal on a table with a ball in the seat and set a fairly heavy weight (5 lbs or so) on the ball, it would probably form a tight seal in a few days. You could verify using a microscope or a loup. Might not take that long. Good advice. I've never tried this. I have also never met a Teflon seal that I could not get to seat. Some have frustratingly required multiple attempts. Edited September 3, 2020 by Shadrach 2 Quote Link to comment Share on other sites More sharing options...
Nukemzzz Posted September 3, 2020 Report Share Posted September 3, 2020 4 hours ago, Shadrach said: I appreciate your experience and statistical analysis. However, 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 a 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 to ways 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. My starting point was "it wasn't working and then it stopped" with no external influences like: someone jacking with it. Even given that, it could be the the inlet starts leaking and nobody notices, then months/years later the outlet fails and that's how you practically end up with both of them failed at the same time. This is the possibility I tried to raise at the end of my prior post but I maybe didn't explain it well. Though I can't imagine these teflon seats deciding to leak with normal use. They should be very robust. I think the weak point in this pump is the elastic seals/o-rings. Probably everything is fine until a seal wears-out or ages-out and leaks. Then the rebuild process introduces risk of handling damage and debris...then new issues arise. Surgery is risky...lol Quote Link to comment Share on other sites More sharing options...
Shadrach Posted September 3, 2020 Report Share Posted September 3, 2020 (edited) 6 hours ago, Nukemzzz said: My starting point was "it wasn't working and then it stopped" with no external influences like: someone jacking with it. Even given that, it could be the the inlet starts leaking and nobody notices, then months/years later the outlet fails and that's how you practically end up with both of them failed at the same time. This is the possibility I tried to raise at the end of my prior post but I maybe didn't explain it well. Though I can't imagine these teflon seats deciding to leak with normal use. They should be very robust. I think the weak point in this pump is the elastic seals/o-rings. Probably everything is fine until a seal wears-out or ages-out and leaks. Then the rebuild process introduces risk of handling damage and debris...then new issues arise. Surgery is risky...lol The problem is many don't know what properly is. Anthony @carusoam believed for years that the first pump was to pressurize the system and the flaps didn't actuate until the second pump. This misconception and others have been often repeated and or mentioned because many of the systems (simple as they are) have not been properly installed, bled and adjusted. The new owner of an old Mooney does not know what he does not know...nor would an A&P that is not intimately familiar with vintage Mooneys. Functioning properly to many simply means the flaps go down when I pump and come up when I flip the return switch. That's good enough to get by. Really functioning properly means precisely 4 pumps from start to lock out, no slop in the system and 10-12 seconds to return to the up position. I would bet there are many birds out there that do not meet the standards listed above. As much as I like the system, I now understand why so many do not. Edited September 4, 2020 by Shadrach 1 1 Quote Link to comment Share on other sites More sharing options...
M20F Posted May 4 Report Share Posted May 4 Anyone got a line on where to get the Teflon HE1517 seals these days? Quote Link to comment Share on other sites More sharing options...
M20F-1968 Posted May 12 Report Share Posted May 12 On 5/4/2024 at 8:30 AM, M20F said: Anyone got a line on where to get the Teflon HE1517 seals these days? Send me a PM. John Breda 1 Quote Link to comment Share on other sites More sharing options...
M20F-1968 Posted May 12 Report Share Posted May 12 I was contacted by a Mooneyspacer asking that I make him some teflon seals for the H&E Vintage Flap Pump. I though I would let the group know that I plan on making these for one person. If anyone wants and needs these, Please PM me. John Breda 2 1 Quote Link to comment Share on other sites More sharing options...
MB65E Posted May 12 Report Share Posted May 12 Thanks John. The PM section says you are unable to receive messages. I’ll take 4. Thanks for your contribution to the community. -Matt 1 Quote Link to comment Share on other sites More sharing options...
Shadrach Posted May 12 Report Share Posted May 12 20 minutes ago, MB65E said: Thanks John. The PM section says you are unable to receive messages. I’ll take 4. Thanks for your contribution to the community. -Matt It’s a you problem. I sent him a DM with no trouble. 1 Quote Link to comment Share on other sites More sharing options...
M20F Posted May 14 Report Share Posted May 14 Thanks John sent you a DM these things are unobtanium. Quote Link to comment Share on other sites More sharing options...
Shadrach Posted May 14 Report Share Posted May 14 Has anyone verified that the seats are the same for the pre-66 (?) birds? On the early applications, the O-ring is positioned on the Teflon valve seat (a la the OP's). On the later models, maybe 66 and later the o-rings are positioned in machined grooves on the opposing pump half. 1 Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted May 15 Report Share Posted May 15 On 5/12/2024 at 10:18 AM, MB65E said: Thanks John. The PM section says you are unable to receive messages. I’ll take 4. Thanks for your contribution to the community. -Matt On 5/12/2024 at 9:48 AM, M20F-1968 said: I was contacted by a Mooneyspacer asking that I make him some teflon seals for the H&E Vintage Flap Pump. I though I would let the group know that I plan on making these for one person. If anyone wants and needs these, Please PM me. John Breda I couldn’t DM you either, but it would be awesome if I could get in on this for 4 as well? Thanks so much for building these! Drew Quote Link to comment Share on other sites More sharing options...
Hradec Posted May 16 Report Share Posted May 16 I'm interested in purchasing the teflon seals also. I sent a msg a few days ago. Thanks Glenn Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.