M20 Hydraulic Pump Flap Diagram

[Tcraft938]

On 4/16/2020 at 12:45 PM, Skates97 said:

Will have to look into that. That would make sense, they look like they are retracting at the same rate, just the left side gets there first.

Skates, I'm in annual right now and mentioned your post to my IA.  He said, "perfect because I noticed that on yours to a lesser degree and today we are going to check control throws".  This is his first time to inspect this airplane so he is really looking into everything.  Also he is sick of working on one manufacturer and "enjoy the superior design of the Mooney".  We found one flap extended 4 degrees lower than the other and one retracted higher than the other (over retracted so to speak).   That made for an almost 2 second difference in apparent retraction speed.  Lubricating the entire mechanism from the actuator on out to the flap hinges corrected about half that.  He adjusted them to specification per SM and TCDS and they are dead on for retract speed and for some reason, my 7 pumps to put them down became 5 to 5 1/2.  Hopefully your fix is just as straightforward.

[Nukemzzz]

So another update....

The pump is back in and bled and the retraction adjuster still doesn’t work. The spring goes solid too early and so you can hold the ball down with the adjuster that way. But if you back the screw out any the flaps Snap up. 
 

I think it’s the wrong spring or I need part 23. 

stopping for now. 

[Culver LFA]

14 hours ago, Nukemzzz said:

So another update....

The pump is back in and bled and the retraction adjuster still doesn’t work. The spring goes solid too early and so you can hold the ball down with the adjuster that way. But if you back the screw out any the flaps Snap up. 
 

I think it’s the wrong spring or I need part 23. 

stopping for now. 

 

Hello Nukemzzz,

Part #23 (HE1677) is an aluminum crush washer, dimensions are:

O.D. 0.417"

I.D. 0.260"

Thickness 0.060"

 

If you would like to measure the spring (HE1518) for comparison,  0.182" in diameter and 0.518" in height.

 

It was mentioned earlier in this thread, can't remember if it was you or someone else, that the plunger is tight in the bore with the new o-ring installed, I don't think that should be the case. Either the o-ring is the incorrect size or it was installed dry?  Once assembled, the plunger should move freely with rotation of the cam arm (#15) with your fingers.  You'll feel the plunger moving freely against the spring pressure.

I hope this info helps you out!

Joe

[N201MKTurbo]

20 hours ago, Shadrach said:

Thanks, Indeed looking at yours I have learned something.  Mine is darker but certainly is made from the same material. That does not look like solid brass. I stand corrected.

It is Alodine

http://www.greencoat.co.il/en/806

 

[Shadrach]

40 minutes ago, N201MKTurbo said:

It is Alodine

http://www.greencoat.co.il/en/806

 

Agreed. My memory is that it feels much heavier than Aluminum. My assumption on the composition was driven by perceived heft as much as appearance.

[Nukemzzz]

2 hours ago, Culver LFA said:

 

Hello Nukemzzz,

Part #23 (HE1677) is an aluminum crush washer, dimensions are:

O.D. 0.417"

I.D. 0.260"

Thickness 0.060"

 

If you would like to measure the spring (HE1518) for comparison,  0.182" in diameter and 0.518" in height.

 

It was mentioned earlier in this thread, can't remember if it was you or someone else, that the plunger is tight in the bore with the new o-ring installed, I don't think that should be the case. Either the o-ring is the incorrect size or it was installed dry?  Once assembled, the plunger should move freely with rotation of the cam arm (#15) with your fingers.  You'll feel the plunger moving freely against the spring pressure.

I hope this info helps you out!

Joe

Thanks for the info!  Where did you find the specs of part 23?  What is your understanding of the function of this part?

[Culver LFA]

3 hours ago, Nukemzzz said:

Thanks for the info!  Where did you find the specs of part 23?  What is your understanding of the function of this part?

Those aren’t exactly specs but measurements off my actuator when it was apart, I’m a bit of a perfectionist and waste a lot of time documenting things I’ll probably never need. 
I suppose it is possible that the crush washer helps center the ball in the bore if the adjuster is backed off and/or prevent coil bind/spring damage if the adjuster is turned in too far.

[Immelman]

I am late to the party, but...

1) I am very appreciative of the time and patience Shadrach gave to me as I battled a similar problem. Ross, once again, thank you from me personally and on behalf of all Mooney pilots. Your "12-step" thread is very useful.

2) nukemizz, thank you for the diagram. It too is a great help for someone who will get into this project. The more information the better.

3) I had a similar problem, after rebuild to correct a leak. In my case the flaps would bleed up very, very slowly. As in minutes, hours, or days, depending on the phase of the moon etc.. and ended up buying another pump from a scrapped Mooney for parts... and got things working. I SUSPECT the issue was the ball (part 24) or its seat (in part 5, as photographed in this post (https://mooneyspace.com/topic/33869-m20-hydraulic-pump-flap-diagram/?do=findComment&comment=576813).  I tried staking the ball.... and my calibration for staking, or material used, might have been the culprit. I still have my old pump body, and it could likely be resurrected.

4) The issue with this system is testing it. You make a fix, and without a good testbench setup to check for leak-down, all you can do is put it back in the plane, bleed the system, and hope, and that is a job requiring time, mess, fluid, and assistance. This is what led me to purchase a scrapped pump for parts. On Ross' suggestion I was hunting around for a simple hydraulic pump to create a testbench but could not find an economical solution, and also did not see a way to get something with an appropriate amount of pressure to simulate the system.

5) Ross has made note that the main difficulty is bleeding the system. Maybe I got lucky but I never had a problem bleeding the system. I used a garden sprayer, plastic tubing, pipe clamps, and EXTRA fluid and just bled and bled until I was getting no bubbles out of a piece of small tubing connected to the hydraulic reservoir overflow pipe. That was my method and it worked well. Buy extra fluid if you do this project! Get a gallon or half gallon.

6) My pump had washer/spacer #23. It looked like something machined vs off-the-shelf. I don't remember if the scrapped one did. I could not figure out its purpose. Nukemizz, your last post suggests that is its purpose. To keep the spring from bottoming too early?? Hard for me to visualize the rebuild now 6+ months later.

7) The bleed-off screw (#26) is very, very, very touchy. Don Maxwell (I think?) noted 1/8 turn makes a big difference. That's 45 degrees. I am going to revise that to suggest 5 degrees of turn makes a significant difference. That's how tight of a tolerance you're looking at to get this right. And when you tighten the big jam nut (#28) that tend to also turn the bleed off screw. I had a big screwdriver trying to hold that steady while I would heighten the jam nut and it always took several attempts to get the retract speed dialed. Patience.

8) Rigging the retract cable also looks to be a point of error. I saw evidence of different setups in the pump that came out of my plane vs the scrapped one. Take time to get this right so that the cable is clamped appropriately.

 

Edited April 18, 2020 by Immelman

[Shadrach]

@Nukemzzz  I was cleaning out my Roadster for a Sunday drive tomorrow and low and behold I saw a familiar sight sticking out from underneath the seat. Confirmed that this pump has no #23 washer. Also confirm that the spring pressure begins before the threads engage.  There is no way the ball would fall off the seat with the threads engaged. I made a short video so you could get a feel for how it looks.  I also added flow direction and pathways to the factory MM diagram attached below.  It is not as easy to read as Nukemzzz's diagram but is another tool to help determine flow and operation.

 

Edited April 19, 2020 by Shadrach

[Shadrach]

3 hours ago, Immelman said:

I am late to the party, but...

1) I am very appreciative of the time and patience Shadrach gave to me as I battled a similar problem. Ross, once again, thank you from me personally and on behalf of all Mooney pilots. Your "12-step" thread is very useful.

2) nukemizz, thank you for the diagram. It too is a great help for someone who will get into this project. The more information the better.

3) I had a similar problem, after rebuild to correct a leak. In my case the flaps would bleed up very, very slowly. As in minutes, hours, or days, depending on the phase of the moon etc.. and ended up buying another pump from a scrapped Mooney for parts... and got things working. I SUSPECT the issue was the ball (part 24) or its seat (in part 5, as photographed in this post (https://mooneyspace.com/topic/33869-m20-hydraulic-pump-flap-diagram/?do=findComment&comment=576813).  I tried staking the ball.... and my calibration for staking, or material used, might have been the culprit. I still have my old pump body, and it could likely be resurrected.

4) The issue with this system is testing it. You make a fix, and without a good testbench setup to check for leak-down, all you can do is put it back in the plane, bleed the system, and hope, and that is a job requiring time, mess, fluid, and assistance. This is what led me to purchase a scrapped pump for parts. On Ross' suggestion I was hunting around for a simple hydraulic pump to create a testbench but could not find an economical solution, and also did not see a way to get something with an appropriate amount of pressure to simulate the system.

5) Ross has made note that the main difficulty is bleeding the system. Maybe I got lucky but I never had a problem bleeding the system. I used a garden sprayer, plastic tubing, pipe clamps, and EXTRA fluid and just bled and bled until I was getting no bubbles out of a piece of small tubing connected to the hydraulic reservoir overflow pipe. That was my method and it worked well. Buy extra fluid if you do this project! Get a gallon or half gallon.

6) My pump had washer/spacer #23. It looked like something machined vs off-the-shelf. I don't remember if the scrapped one did. I could not figure out its purpose. Nukemizz, your last post suggests that is its purpose. To keep the spring from bottoming too early?? Hard for me to visualize the rebuild now 6+ months later.

7) The bleed-off screw (#26) is very, very, very touchy. Don Maxwell (I think?) noted 1/8 turn makes a big difference. That's 45 degrees. I am going to revise that to suggest 5 degrees of turn makes a significant difference. That's how tight of a tolerance you're looking at to get this right. And when you tighten the big jam nut (#28) that tend to also turn the bleed off screw. I had a big screwdriver trying to hold that steady while I would heighten the jam nut and it always took several attempts to get the retract speed dialed. Patience.

8) Rigging the retract cable also looks to be a point of error. I saw evidence of different setups in the pump that came out of my plane vs the scrapped one. Take time to get this right so that the cable is clamped appropriately.

 

Many thanks Jessie! It was nice talking to you.

[Nukemzzz]

3 hours ago, Shadrach said:

@Nukemzzz  I was cleaning out my Roadster for a Sunday drive tomorrow and low and behold I saw a familiar site sticking out from underneath the seat. Confirmed that this pump has no #23 washer. Also confirm that the spring pressure begins before the threads engage.  There is no way the ball would fall off the seat with the threads engaged. I made a short video so you could get a feel for how it looks.  I also added flow direction and pathways to the factory MM diagram attached below.  It is not as easy to read as Nukemzzz's diagram but is another tool to help determine flow and operation.

 

Thanks for checking this. Could you snap a picture of the spring?  It seems to be much longer than mine and likely a smaller wire diameter. My spring only sticks out of the adapter about an 1/4 inch and so it would never reach the bottom of the pocket. 

Seems I either need to buy a spring or make a washer to get this working. 

[Shadrach]

18 minutes ago, Nukemzzz said:

Thanks for checking this. Could you snap a picture of the spring?  It seems to be much longer than mine and likely a smaller wire diameter. My spring only sticks out of the adapter about an 1/4 inch and so it would never reach the bottom of the pocket. 

Seems I either need to buy a spring or make a washer to get this working. 

The spring is tight in the retraction screw. It’s conceivable that if you tightened it all the way down the spring could hang up inside of the retraction screw and not fully extend when the retraction screw is loosened.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited April 19, 2020 by Shadrach

[Nukemzzz]

On 4/18/2020 at 9:07 PM, Shadrach said:

The spring is tight in the retraction screw. It’s conceivable that if you tightened it all the way down the spring could hang up inside of the retraction screw and not fully extend when the retraction screw is loosened.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The mystery deepens. It looks just like mine, yet it’s not possible to slow down the flaps with my setup. It’s got to be the missing #23. Maybe some pumps need them and others don’t. Mine seems to be in the former. After that I’m all out of workable theories. 

I’ll likely get a custom washer made and give it a shot. I’ll report back when I know more. 

[carusoam]

Double check the adjustment screw...

It has a really narrow operating range... (somebody mentioned it briefly above)

That’s when it is already working correctly...

Good luck on the next steps...

Best regards,

-a-

[Shadrach]

Just now, Nukemzzz said:

The mystery deepens. It looks just like mine, yet it’s not possible to slow down the flaps with my setup. It’s got to be the missing #23. Maybe some pumps need them and others don’t. Mine seems to be in the former. After that I’m all out of workable theories. 

I’ll likely get a custom washer made and give it a shot. I’ll report back when I know more. 

The spring is really tight in the screw. If you tightened it all the way down, the spring may have hung up in the screw causing it to remain compressed when you loosened it.

[Shadrach]

2 minutes ago, Nukemzzz said:

The mystery deepens. It looks just like mine, yet it’s not possible to slow down the flaps with my setup. It’s got to be the missing #23. Maybe some pumps need them and others don’t. Mine seems to be in the former. After that I’m all out of workable theories. 

I’ll likely get a custom washer made and give it a shot. I’ll report back when I know more. 

https://www.preferredairparts.com/InventorySearch?filter=1H4sIAAAAAAAEAPNwNTQzN-cCAMvz6q0HAAAA0

[Nukemzzz]

On 4/19/2020 at 11:03 PM, carusoam said:

Double check the adjustment screw...

It has a really narrow operating range... (somebody mentioned it briefly above)

That’s when it is already working correctly...

Good luck on the next steps...

Best regards,

-a-

Late post follow up...you were right. The guy helping me adjust it under the plane while I actuated things gave up to early. I sent the pump to Don Maxwell.  He put it on his test bench and reported nothing was wrong, he just adjusted it and it’s fine. So this missing mystery washer wasn’t needed and it’s likely an error in the parts manual. 

[LantisPDX]

It was really nice to find this posting to try and trouble shoot the flap pump. I spent the better part of my day working on it with my mechanic yet made little improvement to the problem. I used the troubleshooting diagram from Nukemzzz and I believe we narrowed the problem down to the adjustment screw segment. 

The symptoms for mine are almost no adjustability on retract time. If we screw the adjustment screw in, it goes from a 4 second retract at best, directly to letting the flaps bleed up even with the selector down. My understanding is that it should lock up the flaps when tightened in, so that's clearly a problem. 

We have been having lots of trouble with the flaps bleeding up. The handle is staying where it is left and not returning up. On the previous attempts we got it to 4-4.5 pumps for fully down so I don't think it's a bleeding problem.

I am honestly really stumped at what we should try next. Maybe sending it to Don Maxwell to bench test is the next best step. I didn't realize that was an option! 

For what it's worth mine had the #23 washer. I measured and it matched the specs provided here. It had a very little scoring but it does not seem to be a sealing surface. We tried it with and without, no noticeable difference was made.

Happy for any suggestions you might have for me. I will take pictures if we pull it back apart another time tomorrow.

[N201MKTurbo]

1 hour ago, LantisPDX said:

It was really nice to find this posting to try and trouble shoot the flap pump. I spent the better part of my day working on it with my mechanic yet made little improvement to the problem. I used the troubleshooting diagram from Nukemzzz and I believe we narrowed the problem down to the adjustment screw segment. 

The symptoms for mine are almost no adjustability on retract time. If we screw the adjustment screw in, it goes from a 4 second retract at best, directly to letting the flaps bleed up even with the selector down. My understanding is that it should lock up the flaps when tightened in, so that's clearly a problem. 

We have been having lots of trouble with the flaps bleeding up. The handle is staying where it is left and not returning up. On the previous attempts we got it to 4-4.5 pumps for fully down so I don't think it's a bleeding problem.

I am honestly really stumped at what we should try next. Maybe sending it to Don Maxwell to bench test is the next best step. I didn't realize that was an option! 

For what it's worth mine had the #23 washer. I measured and it matched the specs provided here. It had a very little scoring but it does not seem to be a sealing surface. We tried it with and without, no noticeable difference was made.

Happy for any suggestions you might have for me. I will take pictures if we pull it back apart another time tomorrow.

I would re-coin the 3/16 ball in its seat. 

[Nukemzzz]

12 hours ago, LantisPDX said:

It was really nice to find this posting to try and trouble shoot the flap pump. I spent the better part of my day working on it with my mechanic yet made little improvement to the problem. I used the troubleshooting diagram from Nukemzzz and I believe we narrowed the problem down to the adjustment screw segment. 

The symptoms for mine are almost no adjustability on retract time. If we screw the adjustment screw in, it goes from a 4 second retract at best, directly to letting the flaps bleed up even with the selector down. My understanding is that it should lock up the flaps when tightened in, so that's clearly a problem. 

We have been having lots of trouble with the flaps bleeding up. The handle is staying where it is left and not returning up. On the previous attempts we got it to 4-4.5 pumps for fully down so I don't think it's a bleeding problem.

I am honestly really stumped at what we should try next. Maybe sending it to Don Maxwell to bench test is the next best step. I didn't realize that was an option! 

For what it's worth mine had the #23 washer. I measured and it matched the specs provided here. It had a very little scoring but it does not seem to be a sealing surface. We tried it with and without, no noticeable difference was made.

Happy for any suggestions you might have for me. I will take pictures if we pull it back apart another time tomorrow.

I agree that it sounds like you might need to recoin the seat that is below the adjustment screw.  I don't understand how screwing in could cause the seat to leak.  That's a mystery to me...doesn't add up. 

BTW, Don told me that the adjustment range is about the width of the screwdriver blade while setting the retract speed.... so it is extremely sensitive...too sensitive in my opinion.  

[N201MKTurbo]

57 minutes ago, Nukemzzz said:

I agree that it sounds like you might need to recoin the seat that is below the adjustment screw.  I don't understand how screwing in could cause the seat to leak.  That's a mystery to me...doesn't add up. 

BTW, Don told me that the adjustment range is about the width of the screwdriver blade while setting the retract speed.... so it is extremely sensitive...too sensitive in my opinion.  

Yep, just tightening the jamb nut takes it from fast to slow.

[carusoam]

Seems like you have all the details...

Inviting Ross to the conversation may be helpful...

Ross knows the flap pumps incredibly well...  aka flap pump whisperer...

@Shadrach

Best regards,

-a-

 

[Shadrach]

On 1/26/2021 at 2:04 PM, N201MKTurbo said:

Yep, just tightening the jamb nut takes it from fast to slow.

Tightening the jam nut often turns the screw with it. It can be a challenge hold the screw in its exact desired position while tightening the jam nut. That’s why many mechanics quit at “good enough”. It’s true that the functional adjustment range is just a few degrees. It’s not a very precise set up but it can be set up precisely. As others have stated, the ball does not seem to be seating. Don may be the easiest solution.

Edited January 28, 2021 by Shadrach

[N201MKTurbo]

27 minutes ago, Shadrach said:

Tightening the jam nut often turns the screw with it. It can be a challenge hold the screw in its exact desired position while tightening the jam nut. That’s why many mechanics quit at “good enough”. It’s true that the functional adjustment range is just a few degrees. It’s not a very precise set up but it can be set up precisely. As others have stated, the ball does not seem to be seating. Don may be the easiest solution.

But it does seem to maintain a stable rate after it is adjusted. Maybe there was a method to their madness.

[Shadrach]

35 minutes ago, N201MKTurbo said:

But it does seem to maintain a stable rate after it is adjusted. Maybe there was a method to their madness.

Agreed. I think there is a lot to like about the system and its few challenges are surmountable.