Flap Pump Leak

[AZOutlaw]

I noticed a lot of red fluid on the belly of my 65D.  Removed the panels and determined it was from the flap pump.  What I found is that when lifting the lever, before the down pump stroke, it was pushing fluid out the small hole in the back of the pump.  I assume I have bad O rings inside and that there probably shouldn't be fluid on the back side of the plunger.  Anyone have experience with this?

[Wildhorsesracing]

We just found the same thing in mine last week during the annual, replaced all three O-rings and it works fine.  It's actually a pretty simple but messy task.  Took about two hours to R&R and replace the rings.

[N601RX]

It has a oring, leather washer and spiral ring inside as well as a few other seals. Lasar sells a kit that has everything in it. Don't loose any of the balls, springs or ball seats when it comes apart. You may want to check the condition of the rear slave cylinder and the 2 hoses also. It's easier to do it all at once if needed. It's a little hard to get oil back into the pump as it will tend to airlock until it gets some oil back in it.

[Andy95W]

If at all possible, fill the pump with as much hydraulic fluid as possible before installation. This primes the pump and will save a lot of pumping and frustration later on.

[Wildhorsesracing]

My flap cylinder had a Tee fitting and a cap, we used a pressure bleeder with the valve open (pulled out) to push fluid back up into the reservoir.  Make sure you put a hose on the reservoir cap as it'll make a mess inside the cockpit.  I wish I had taken pictures, it was quick and easy to backflush and worked perfectly.

[AZOutlaw]

Thanks for all the comments.  I contacted Lasar but probably won't hear back until Monday.  I haven't had much for brakes lately either so this seems like a great time to flush the whole system.  Although Flaps and Brakes just slow me down, and Mooneys a made to go fast, they do seem to be vital components.  I'll post results when done.

[rbridges]

  On 1/11/2015 at 2:29 AM, Wildhorsesracing said:

We just found the same thing in mine last week during the annual, replaced all three O-rings and it works fine.  It's actually a pretty simple but messy task.  Took about two hours to R&R and replace the rings.

 

easy enough for the average owner and IA to do?

[Wildhorsesracing]

  On 1/11/2015 at 3:43 PM, rbridges said:

easy enough for the average owner and IA to do?

 

Yes - the O-rings are simple once you have the unit apart, the unit is in a tight place but with some mechanical ability you should be able to remove it, take it apart on the bench and reassemble  - I did it with my A&P mentoring me.  

 

FWIW: We spent more time looking thru his stock shelves for the proper O-rings than it took me to disassemble & reassemble the pump & valve!

 

 

 

YMMV - I build racecars for a living so what I consider easy could prove difficult for some folks.

[47U]

Like Wildhorse says, not overly difficult if you are mechanically inclined. Check with your A&P/IA to see how much rope they feel comfortable giving you. The mx manual has schematics of system and components. Ordering just the o-rings/seals you need vs the Mooney overhaul kit will save you some dough.

If your flap actuator hasn't been resealed in a while, you might consider replacing the seals there, too. Bleeding the flaps might be the most challenging part so why risk having to do it again only a few years down the road.

How old are the hoses in your flap system? Another common oversight, mine were 47 years old when I changed them during my first annual five years ago.

[carusoam]

I learned from my C that I'm not very mechanically inclined.

The steel balls ran away into a floor drain...

It took a dab of grease to hold it in place while reassembling it. A simple gravity challenge...

I am sure my mechanic said 'don't lose that' prior to the chase.

Also, check the age of the hoses from the reservoir. At 40 years of age, they have a tendency of cracking prior to leaking into the belly.

If you are losing the cherry fluid, and it is congealing on the inside of the belly panel, expect old hose may be an issue...

This is on the low pressure side of the pump. The hoses get ignored pretty easily...

Best regards,

-a-

[AZOutlaw]

Got my kit in from Lasar and took the pump apart today. Do any of you know if the "plunger" end comes apart? Two leather rings and one standard rubber O ring go on the plunger. I'm afraid the leather rings will get really stretched out of shape while putting them on. There also has to be an O ring where the shaft goes out the cap. Any way to get to that O ring?

[Wildhorsesracing]

It was easy to get the O-ring out - but a challenge to get the new one back in!  We used a ring pick to pull it out and put it back in.  I did not replace the leather, just the o-ring.

[N601RX]

The shaft slides out of the cap and then you can use a dental pick to get the oring and other stuff out.  The leather washer can be worked over the piston.  Be sure it is lubed really well when sliding it past the threads so it doesn't get cut.

[AZOutlaw]

Just a quick follow up....I got the LASAR kit installed and all works great with no leaking.  It took a lot of pumping to get fluid back in the system.  Had to remove the cap at the T fitting at the cylinder to bleed it out.  It seems now that 2 pumps gives me a lot more flaps than it did before so I might need to learn to fly all over again but think I can handle it.  Thanks for all the help.  If anyone wants to come help re-install the 983 screws in the belly, that would be great!  Now onto the brakes again.

[Wildhorsesracing]

  On 1/23/2015 at 2:14 PM, AZOutlaw said:

If anyone wants to come help re-install the 983 screws in the belly, that would be great!  

 

Order the one piece belly from LASAR and you'll cut that down to under 50 screws

[airplanesfly]

 I am trying to replace the leather washers and I cannot get them on without overstretching and breaking them. I soaked the washers in Hyd fluid for 2 days before attempting to stretch them. Any hints, tips, suggestions? Is there an oring replacement for the leather washer? I Was looking around and found the Parker parbak oring and a PFTE oring that could potentially be a sub for the leather washer. Both are listed in the Parker oring handbook, as well as the leather one. Has anyone used any of these orings?

[C-GHIJ]

I've had to rebuild mine at least every 2 years to keep it working properly.  There are no new ones so i'll keep rebuilding it.

[N201MKTurbo]

FWIW. I had a F for 19 years. I did everything wrong and right you can do with that pump. If the pump is spongy, don't waste a lot trying to bleed it. Go up as high as you can 13500 or so, slow down and actuate the flaps about 10 times. They will be hard as a rock. The low ambient pressure helps to get the air out.