Positive Control not so Positive Right Now

[Yetti]

Just spoke with Brittian Said they should be back open in Summer 2020.

When I had mine done, they said usually the red line fails first.   

Just for fun you may check where the wheel well as the tubing gets exposed there.

[MBDiagMan]

Thanks a bunch Clarence!  Exactly what I needed to know!

Thanks Yetti!  I will look around in there.

Edited December 17, 2019 by MBDiagMan

[MBDiagMan]

Okay, here’s where I’m at now:

I have checked both actuators as best I can and they seem tight although I’m not totally confident of my test connection on the aileron connection.  I have the rudder line disconnected and plugged and the aileron connection disconnected and plugged and can’t pull a vacuum on the line at the TC.  I will check the connections and retest before I tear anything else apart, but it seems to be a leak somewhere in the lines.  Are there any lines or connections That are more failure prone than others?

Edited December 19, 2019 by MBDiagMan

[Yetti]

Brittian said the red lines fail faster than the green tubing.   

 

anticipating your next question

 

 

[Hector]

In my M20C there is a bulkhead connection right behind the large fuselage door on the LH side (I think the battery door on your J). You could disconnect the red/green hose there and just vacuum test the portion going out to the wing. If you can pull a vacuum there, then you probably have a leak in the section of the hose running along the LH side of the cockpit but you can now check that as well by plugging the connection at this bulkhead. Not sure the J has the bulkhead connection same as a C but you can easily check that.

 

I had the same issue as you and I traced it to the servo. There was no tear on the rubber itself but the electrical tape that holds it to the can was in very bad shape and was leaking through there. Took the servo out and re-taped it and good as new. Lost a bit of skin in my knuckles getting the servo in and out but with the right tools it was not too bad.

 

 

Sent from my iPhone using Tapatalk

 

[MBDiagMan]

Is the hard red line available?

[Shadrach]

On 12/19/2019 at 5:32 PM, MBDiagMan said:

Is the hard red line available?

Probably but I have never seen one fail. 

Go after the low hanging fruit. Pull the instrument access panels and verify all hoses are where they should be. What year is your F? 

Edited February 3, 2020 by Shadrach

[Yetti]

7 minutes ago, Shadrach said:

 

Go after the low hanging fruit. Pull the instrument access panels and verify all hoses awhere they should be. What year is your F? 

I think we are passed that phase.   I think he has it narrowed down to a leak in the red line.   There is a T connector behind the panel in the baggage compartment on the pilots side.

[MBDiagMan]

67 model made in Dec 66.

I think I will have to pull the belly pan for good access to the Tee.  The connections between soft line and hard line look to be difficult to service.

Im going to get some different caps or something to cap the vacuum lines for testing the lines alone.  When I started, I could pump some vacuum on the red line and it would hold for a little bit before leaking down.  Testing the lines alone I can’t get any vacuum at all.  Gonna have to do some more testing tomorrow before doing anything further.  Right now I have the line removed from both actuators and capped, doing the testing from the line disconnected from the TC with a vac source.

Edited December 20, 2019 by MBDiagMan

[brad]

This thread just saved me a bunch of aggravation.  Got her back with the new interior.  Auto pilot started drifting to right.  Couldn't correct on turn coordinator.  Had local Avionics shop check out.  Gave them copy of the schematic posted earlier in the thread.

Sure enough, when the new side panels were installed, a screw was through the green line.  Easy fix!

Thanks!

[MBDiagMan]

Without digging deeply.... it seems like the tubing size near the TC is smaller than that found at the aileron.  Does anyone know the tubing dimensions to save me a trip to the hangar?

[MBDiagMan]

Okay, the tubing in the wing and the rudder appear to be the same.  All 3/8” OD.   With the lines at the actuators disconnected and plugged, applying vac at the TC end will build a little and then leak off in a second or two.

If I had any confidence that the TruTrakwould be certified in the next couple of months I wouldn’t worry with it, but I have no confidence that it will EVER beavailable for a Mooney.

[Shadrach]

On 12/20/2019 at 6:42 PM, MBDiagMan said:

Okay, the tubing in the wing and the rudder appear to be the same.  All 3/8” OD.   With the lines at the actuators disconnected and plugged, applying vac at the TC end will build a little and then leak off in a second or two.

If I had any confidence that the TruTrakwould be certified in the next couple of months I wouldn’t worry with it, but I have no confidence that it will EVER beavailable for a Mooney.

How much vacuum are you pulling?  8"-10" HG is plenty.  Are you using a mighty vac?  Why not try to actuate each section with with actuators connected?  If you are in there pulling hoses and hoping for the best you have a good chance of causing as many problems as you're solving.  Behind panel leaks and misroutings are common.  Actuator leaks are common.  The green and red stuff is pretty tight until someone starts messing with it.  

The tubing that runs from the pivot valve to the TC and then to filters and a coupler on the left side of the instrument bay is flexible rubber black tubing and turns to swiss cheese about every 6-8 years.

The manuals are here.  Testing for each circuit is outlined.  

Also, don't set your vacuum to 5.00 HG that will trigger the "High Vacuum" annunciator.

Edited February 3, 2020 by Shadrach

[MBDiagMan]

I have lines disconnected from actuators and plugged to test the lines alone.  I wish I could pull five with the misty vac.  I cant get it past one inch for more than a second.

Thanks for the tip about not setting the vac over five.  I thought it was supposed to be 4.5 to 6.5.  I guess I get that from the Cessna.

it appears that replacing the line that goes through the wheel well and through the wing can be accomplished without too much trouble.  The one from under the panel to the tee near the rear wing root appears to be the challenging one that could end up causing trouble.

Edited December 21, 2019 by MBDiagMan

[Shadrach]

19 minutes ago, MBDiagMan said:

I have lines disconnected from actuators and plugged to test the lines alone.  I wish I could pull five with the misty vac.  I cant get it past one inch for more than a second.

Thanks for the tip about not setting the vac over five.  I thought it was supposed to be 4.5 to 6.5.  I guess I get that from the Cessna.

Per the Operating limitations section of the owner’s manual

High vac is >= 5.00HG

Low vac is <= 4.50 HG

 

my my concern is you’re not getting a good seal. I have several actuators in my hangar. some are old and deteriorated. But all still hold a vacuum. These systems do fail but it’s usually pretty simple. The worst case situations I’ve seen are self induced. Keep us posted!

 

[MBDiagMan]

Thanks for the warnings and info about max vac.

i have no leaks int the actuators that I can tell.  I am down to testing nay the lines and they won’t hold a vacuum.  The actuators are isolated at this point.

[Yetti]

The tubing runs down the back edge of the wing through really big holes.  Just tape the new to the old tubing and pull.

Pull the pilot panel and the baggage compartment panel on the Port side.   Then just feed the tube behind the passenger panel

[MBDiagMan]

Okay, with the whole fam family home for Christmas I haven’t had time for this.  My plan is to take off the belly pan below the tee and see if I can isolate the leak.  I have to get the tubes tight before I can move onto the actuators if necessary, but I now believe the actuators to be tight.

I hope to get on this Tuesday.

[Igor_U]

23 hours ago, MBDiagMan said:

 My plan is to take off the belly pan below the tee and see if I can isolate the leak.  

I don't think you'll have an access to the TEE's through the belly panel. On my plane (2 line numbers behind yours) access is difficult as it's in baggage compartment behind the LHS carpet panel. It is low and in almost line with aft bulkhead so it's difficult to undo it and connect a vacuum pump.

Have a look at the picture, TEE's are in lower left corner under the white battery cable.

 

 

[MBDiagMan]

Wow Igor!  What a timely post.  I was just sitting here talking to my lovely wife about dropping the belly pan tomorrow.  We still have family here and I am trying to minimize my time away from the house, but I really want to do it if it produces results.  

I can see the tee by looking forward from the open left exterior panel.  I will use your picture for perspective and take another look.  I think you saved me a bunch of wasted time.  I appreciate this information and the picture a BUNCH!

BTW, have all your red tubes and connectors remained tight?

Edited December 31, 2019 by MBDiagMan

[Igor_U]

17 hours ago, MBDiagMan said:

BTW, have all your red tubes and connectors remained tight?

I think I had a tiny leak in a lest side since I have to make corrections on a TC (roll control) but this could be also due to deteriorating rubber (black) tubing under the panel. I just replaced those the other day (after 10 years) while waiting for  my SureFly  magneto hence the LHS interior panels are removed to run the power wire.

I believe Red and Green tubing is good (at least what I see) and can't really see that can deteriorate like rubber tubing.

I will disconnect the Red at the TEE and apply vacuum and check the line through wing and servo for possible leaks. as you can see, TEE is not really accessible. RHS servo was rebuilt by Brittain 3-4 years ago due to leak and THAT was pain to remove. 1/2" articulated ratcheting wrench is a must for removal/install.

 

Good luck.

[MBDiagMan]

Okay here’s the latest.  The line in the wing had a section of line replaced and the splices were done by simply slipping 3/8” fuel line over the hard line and it was loose.  I did some good splices and now have it tight all the way to the aileron actuator.  I expect to connect the actuator tomorrow and see if it’s all tight.  I got some bellows from a fellow Mooneyspacer so I am prepared to reboot the actuator if necessary.

I might actually get there folks.  It’s been an education and I appreciate all the help!

[MBDiagMan]

Everything is together and tests good with the miteyvac.  Now I have to adjust the vac regulator and do a taxi test.  I’m headed to my grandsons basketball game then volunteer work at the flight museum.  May not get the test completed today, but I fully expect to do so by the end of the day Monday.

If this works it will get me by until(if) the Trutrak gets certified.

[LANCECASPER]

9 hours ago, MBDiagMan said:

Everything is together and tests good with the miteyvac.  Now I have to adjust the vac regulator and do a taxi test.  I’m headed to my grandsons basketball game then volunteer work at the flight museum.  May not get the test completed today, but I fully expect to do so by the end of the day Monday.

If this works it will get me by until(if) the Trutrak gets certified.

The moment you get it working perfectly. TruTrak will announce certification.

[MBDiagMan]

Yes, that’s why I did it.  If I hadn’t fixed it, there would NEVER be certification and availability.  Murphy!