Which servo is leaking

[TheTurtle]

my plane lists heavily to the left when I release the thumb valve for the brittian wing leveler/AP.   Using the trim knob on the turn coordinator doesnt help.

Does that mean the left or right servo is leaking? 

[takair]

Left.  

[N201MKTurbo]

Cheap bastards troubleshooting method.

Depending what year you have. There are two plastic tubes that terminate under the instrument panel than transition to rubber hoses. remove the hoses one at a time from the turn coordinator valve. Stick it in your mouth and suck real hard until the yoke moves. then stick your tongue on the end of the tube. If it holds the suction the servo is good. If the suction bleeds off the servo needs fixin.

Each hose goes to two servo bellows. One goes to the right aileron and right rudder. the other to the lefts.

Edited March 12, 2018 by N201MKTurbo

[kpaul]

39 minutes ago, N201MKTurbo said:

Cheap bastards troubleshooting method.

Depending what year you have. There are two plastic tubes that terminate under the instrument panel than transition to rubber hoses. remove the hoses one at a time from the turn coordinator valve. Stick it in your mouth and suck real hard until the yoke moves. then stick your tongue on the end of the tube. If it holds the suction the servo is good. If the suction bleeds off the servo needs fixin.

Each hose goes to two servo bellows. One goes to the right aileron and right rudder. the other to the lefts.

This sounds like when we used to have the new guys test the airspeed indicator on the F-16 by blowing on the pitot tube...made for some great photos.

[N201MKTurbo]

6 minutes ago, kpaul said:

This sounds like when we used to have the new guys test the airspeed indicator on the F-16 by blowing on the pitot tube...made for some great photos.

Yes, but this is done in the privacy of the foot well.....

 

A lot of pilots think their planes are ladies...

If so why do they have pitot tubes?

Edited March 13, 2018 by N201MKTurbo

[Yetti]

How does it do on the ground test?

[TheTurtle]

10 minutes ago, Yetti said:

How does it do on the ground test?

not sure...  I know about the ground test but for some reason havent done it..  Ill give that a shot tomorrow.  Im pretty sure I know where the servo is leaking.  I taped it up when I was first fiddling with the PC system but I need to remove the servo so I can do a better job of it.

[drapo]

Send us some pictures 

[N201MKTurbo]

To tape the servo in place, take an 1/8 inch rod about a foot long. Wrap enough tape on the end of the rod to go around the servo a couple of times. Use the rod as the tape dispenser. You can keep the tape tight and straight all the way around. It is impossible to do it with a roll of tape.

[TheTurtle]

1 minute ago, N201MKTurbo said:

To tape the servo in place, take an 1/8 inch rod about a foot long. Wrap enough tape on the end of the rod to go around the servo a couple of times. Use the rod as the tape dispenser. You can keep the tape tight and straight all the way around. It is impossible to do it with a roll of tape.

good idea.  Blindly attaching the new tubing to the back of those things was real pain.  I was kind of dreading taking it out.

 

[Igor_U]

If that doesn't work, you can always remove the servo from the wing.

Not easy but it really helps to have one of these 1/2" wrenches:

 

[Vance Harral]

Removing the servo from the wing isn't particularly difficult if you're willing to disconnect the aileron rod link.  If you do, you can swing the aileron up out of the way, and there's a clever hole right there into which you can insert a socket wrench extension.  Leads right to the nut on the back of the servo.

[TheTurtle]

On 3/13/2018 at 6:36 AM, Vance Harral said:

Removing the servo from the wing isn't particularly difficult if you're willing to disconnect the aileron rod link.  If you do, you can swing the aileron up out of the way, and there's a clever hole right there into which you can insert a socket wrench extension.  Leads right to the nut on the back of the servo.

My hole's not big enough.  I wonder what the FARs and my IA would say about hangar fairys slightly enlarging that hole?  

 

[Vance Harral]

Hrmph, sorry about that.  I just assumed this was the same on all airframes that had the Brittain aileron servos, but clearly not.  I'll try to remember to take a photo of mine next time I'm out at the hangar.

[Igor_U]

Yes,

I seem to remember a small hole on my plane as well.

Not surprising considering your plane came off the lane few months after mine.

[Stanton R]

I know of an incident that one of the chains on the servo  got a kink in it which made it shorter and it wold pull to one side

 

[211º]

My hole's not big enough.  I wonder what the FARs and my IA would say about hangar fairys slightly enlarging that hole?  
 

I’m curious how you ended up attacking this - tape on the rod or some swearing and removing the servo.


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[TheTurtle]

10 hours ago, 211º said:

I’m curious how you ended up attacking this - tape on the rod or some swearing and removing the servo.


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swearing and removing the servo via the access panel.  Total PITA.  Also didn't fix the problem to add insult to injury ;).  Oh well needed to be done and what else are you going to spend a saturday doing?

[211º]

swearing and removing the servo via the access panel.  Total PITA.  Also didn't fix the problem to add insult to injury .  Oh well needed to be done and what else are you going to spend a saturday doing?

I was slightly afraid that both of these would be in your response. I’ll update the thread when I attack it.


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[Two7Victor]

Mine did that too so I replaced the obviously bad hoses on back of the turn coordinator.  Still have not been able to test fly (long story why) but hopefully it it's better now.  Fortunately I  have an off switch on the panel to disable PC if there are more problems.