Flap Pump rebuild picture dump

[M20F-1968]

On 5/4/2020 at 2:08 PM, qualleyiv said:

If anyone has any interest, I took a video of rebuilding the pump that I would be happy to post if it would be useful...

I would be interested in seeing the video.

John Breda

[Shadrach]

1 hour ago, TreetopMooney said:

Can I jump in and hijack this thread? I have been lurking for a bit. A and p here. 1965 m20e. Overhauled the pump with the oring kit from laser. I’ve verified the correct placement of springs and ball bearings etc. reinstalled. Used the 12 step plan posted on here by the flap guru. Back-bled with pressure pot. Feels like there is no pressure when trying to pump flaps down. I can pump it down if I have the speed screw adjusted all the way down. It will pump down and hold pressure so the actuator isn’t leaking. In this configuration however it will no retract. If I make a micro adjustment on the retracting speed screw then it will not stay down when pumped down (still with very little to no pressure. Infinite pumps basically). I’m thinking maybe there is an issue with this flap speed retraction adjustment screw but maybe I don’t have enough air out of the system somehow even after back bleeding? Maybe both? If I missed something in my description forgive me. Ask questions and I will try and get back quickly. 

Reads like there is no ball in the valve for the retract circuit. When you adjust the screw all the way down you are completely covering the orifice that ports back to the supply line/reservoir.   If they won’t stay down without doing that, then the check valve in the retract circuit is not working (ball missing or not mating to valve seat).

I suspect that your just pushing fluid in a circle when the retract screw backed out. You are pumping it right back to the supply line.

 

 

 

 

 

[TreetopMooney]

17 minutes ago, Shadrach said:

Reads like there is no ball in the valve for the retract circuit. When you adjust the screw all the way down you are completely covering the orifice that ports back to the reservoir.   If they won’t stay down without doing that, then the check valve in the retract circuit is not working (ball missing or not mating to valve seat).

Ok thanks. I took it back off once and opened it and went through it. I had thought the same thing and verified everything was still there and put back together. So the ball is probably just not seating. Solution on this? New ball? New seat? Springs? All of the above? Thank you in advance and appreciate your flap expertise from previous posts you’ve done!

Edited December 12, 2023 by TreetopMooney

[Fly Boomer]

1 hour ago, TreetopMooney said:

Can I jump in and hijack this thread? I have been lurking for a bit. A and p here. 1965 m20e. Overhauled the pump with the oring kit from laser. I’ve verified the correct placement of springs and ball bearings etc. reinstalled. Used the 12 step plan posted on here by the flap guru. Back-bled with pressure pot. Feels like there is no pressure when trying to pump flaps down. I can pump it down if I have the speed screw adjusted all the way down. It will pump down and hold pressure so the actuator isn’t leaking. In this configuration however it will no retract. If I make a micro adjustment on the retracting speed screw then it will not stay down when pumped down (still with very little to no pressure. Infinite pumps basically). I’m thinking maybe there is an issue with this flap speed retraction adjustment screw but maybe I don’t have enough air out of the system somehow even after back bleeding? Maybe both? If I missed something in my description forgive me. Ask questions and I will try and get back quickly. 

It's a three-year-old thread, so don't worry about hijacking.  Someone will be along shortly to answer your question.

[Shadrach]

3 hours ago, TreetopMooney said:

Ok thanks. I took it back off once and opened it and went through it. I had thought the same thing and verified everything was still there and put back together. So the ball is probably just not seating. Solution on this? New ball? New seat? Springs? All of the above? Thank you in advance and appreciate your flap expertise from previous posts you’ve done!

Ball needs to be lightly staked against the seat. Can be done with a drift and a light tap with a hammer. Unfortunately it will need to be done with the pump out of the plane. You should consider staking all of the balls against the seats while you have it out. Are you sure the spring is the maintaining compression on the ball? Should feel slight compression before the threads engage.

like this:

 

[Saira]

On 1/8/2017 at 6:08 PM, TheTurtle said:

i hooked everything back up today.  I then disconnected the line from the pump to the cylinder and pressure bled until the fluid was coming out the overflow in the res (clamped a tube to drain down to a glass jar).  Tightened everything up and pumped the flaps in on the first try!!.  was a little worse than original in that it took almost 5 pumps for full flaps.  Used to take 4.25ish pumps.  I pumped it with the release open a few times and pumped flaps and released a few times and got it back to 4.25- 4.5 for full flaps.  I also reset the release screw.  My flaps were coming up in less than 5 second.  Probably more like 2 so the ass end would drop when you released flaps on climb out.  I slowed it way down so I think its going to be much smoother transitioning from takeoff to no flaps.  All in all its a nasty messy job and I really hate 5606 but its done and it wasnt to painful of a task.

How did you bleed? I need some help with that part. 

 

[Saira]

On 12/12/2023 at 12:00 PM, M20F-1968 said:

I would be interested in seeing the video.

John Breda

Thank you so much. This thread was amazing 

[TreetopMooney]

On 12/12/2023 at 8:09 PM, Shadrach said:

Ball needs to be lightly staked against the seat. Can be done with a drift and a light tap with a hammer. Unfortunately it will need to be done with the pump out of the plane. You should consider staking all of the balls against the seats while you have it out. Are you sure the spring is the maintaining compression on the ball? Should feel slight compression before the threads engage.

like this:

 

Great news! Sorry it took a while to get back but life happens. Spring was definitively the issue but also found a piece of debris on the plunger that appeared to be from the previous leather sweeper ring on the shaft that had deteriorated. Replaced with new spring and reinstalled. Used 12 step bleed method with pressure pot. Flaps are now better than I’ve had them in 20 years! Thanks again for all the help. The biggest clue was this video. My spring had no springiness left. There is no way that ball was staying in place with the way the spring was before it fixed it!

[Shadrach]

16 hours ago, TreetopMooney said:

Great news! Sorry it took a while to get back but life happens. Spring was definitively the issue but also found a piece of debris on the plunger that appeared to be from the previous leather sweeper ring on the shaft that had deteriorated. Replaced with new spring and reinstalled. Used 12 step bleed method with pressure pot. Flaps are now better than I’ve had them in 20 years! Thanks again for all the help. The biggest clue was this video. My spring had no springiness left. There is no way that ball was staying in place with the way the spring was before it fixed it!

Thanks for circling back. That’s great news! It’s funny, I was just thinking about you today while I was on the phone with a shop in Florida helping them sort through a different hydraulic flap issue. I’m glad you got it all worked out. If you get all the air out of the system it should be precisely four pumps to full flaps and hydraulic lockout.