Brittain

[Shadrach]

Hi Folks,

Long time no post!  I am trouble shooting my PC system, specifically the inability to deactivate the system via the button.  I was flying approaches the other day and depressing the thumb button did nothing.  I went so far as to pull the switch out of the receptacle.  No luck. confirmed PC operation with roll trim while button was removed.  We've checked the switch and plumbing and it meets the specs in the Brittain manual. PC functions perfectly otherwise.  I know that Brittain industries has ceased to be a going concern so it's my hope some one else has encountered this issue.  

[N201MKTurbo]

I would check the valve the button goes to. It should vent the vacuum line going to the turn coordinator. Either the valve is stuck or the vent line is plugged.

[Steve65E-NC]

My wing leveler (65E) had a similar problem.  There is a little metal block called a switch in the parts Manual with about four tubes coming out.  After a confirming phone call to isolate problem, I sent that block to Brittain and they rebuilt it for about $100.  Unfortunately the fellow I talked to who was owner and technical leader and very helpful  recently died and Brittain is looking for a company to take over line and does not answer phone (leave message).  There is probably a ruptured diaphragm or some such  inside that block.  A careful tech or watchmaker,  might be able to repair it.  I called Brittain today looking for a retractable step boot and got the message that they are in limbo. 

If anyone has a source for step boot part #1551, please let me know. 

[Mooneymite]

While the pilot valve mentioned in the previous post is the probable culprit, do not overlook clogged filters.

Cheap fix.  I think if you pull the decals back, you will find they are Fram fuel filters.

[takair]

Mine did a similar thing when I first bought the plane.  If you have the vacuum activated “relay” (aluminum block with tubes, mentioned above) it may be plugged.  There is a screen on the bottom that gets coated with dust, clear tha first.  If not, it may simply be stuck.  They are not too difficult to clean...a typical instrument repairman or avionics bench tech, or watch maker would have no problem.  Might also try tapping on it to see if it frees up, but that is short term fix.

 

[takair]

1 hour ago, Steve65E-NC said:

My wing leveler (65E) had a similar problem.  There is a little metal block called a switch in the parts Manual with about four tubes coming out.  After a confirming phone call to isolate problem, I sent that block to Brittain and they rebuilt it for about $100.  Unfortunately the fellow I talked to who was owner and technical leader and very helpful  recently died and Brittain is looking for a company to take over line and does not answer phone (leave message).  There is probably a ruptured diaphragm or some such  inside that block.  A careful tech or watchmaker,  might be able to repair it.  I called Brittain today looking for a retractable step boot and got the message that they are in limbo. 

If anyone has a source for step boot part #1551, please let me know. 

Don’t have the boot, but my electric conversion is PMA’d.  PM me if interested.

[Shadrach]

5 hours ago, Mooneymite said:

While the pilot valve mentioned in the previous post is the probable culprit, do not overlook clogged filters.

Cheap fix.  I think if you pull the decals back, you will find they are Fram fuel filters.

I change my filters every 5 years whether they need it or not!

5 hours ago, Steve65E-NC said:

My wing leveler (65E) had a similar problem.  There is a little metal block called a switch in the parts Manual with about four tubes coming out.  After a confirming phone call to isolate problem, I sent that block to Brittain and they rebuilt it for about $100.  Unfortunately the fellow I talked to who was owner and technical leader and very helpful  recently died and Brittain is looking for a company to take over line and does not answer phone (leave message).  There is probably a ruptured diaphragm or some such  inside that block.  A careful tech or watchmaker,  might be able to repair it.  I called Brittain today looking for a retractable step boot and got the message that they are in limbo. 

If anyone has a source for step boot part #1551, please let me know. 

I think what you are referring to is called the Pivot valve (see illustration) I think I have a diaphragm issue. I’ve confirmed the switch is holding and dumping vacuum. 

[takair]

21 minutes ago, Shadrach said:

I change my filters every 5 years whether they need it or not!

I think what you are referring to is called the Pivot valve (see illustration) I think I have a diaphragm issue. I’ve confirmed the switch is holding and dumping vacuum. 

On the bottom of the “pivot” valve (think they meant “pilot”) there is a screen.  That screen allows the diaphragm to relive pressure when you push the button.  It can get so much dust on it that you may not even notice that there is a screen there.  Not sure if that is the filter you are referring to, or the more typical replaceable ones.

[Shadrach]

36 minutes ago, takair said:

On the bottom of the “pivot” valve (think they meant “pilot”) there is a screen.  That screen allows the diaphragm to relive pressure when you push the button.  It can get so much dust on it that you may not even notice that there is a screen there.  Not sure if that is the filter you are referring to, or the more typical replaceable ones.

Referring to replaceable filters. Screen is clear. Spring loaded Valve moves freely, but never changes position under vacuum.

Edited July 10, 2018 by Shadrach

[David Lloyd]

If I remember correctly, not much inside that pilot valve.  Only moveable part is a spool that might get stuck from 50 years for semi clean air.  Disassemble, clean, very lightly oil, reassemble.  Tell no one.

[65C_flier]

Now I am confused! I can not find a pilot valve anywhere in my PC system (65C with electric yoke button mod). Does the electric yoke switch with solenoid (part number 4085) replace the pneumatic pilot valve?

[carusoam]

Well....

That is a good question...

The Pilot has a button/valve under his thumb....

If that button has been removed and replaced with the electric switch powered valve on the panel...

That could make it the pilot’s switch. And pilot’s valve... 

I reviewed the drawing that Ross posted and didn’t quite get the reason why it was called the pilot valve...

I think I do now...

Best regards,

-a-

[MyNameIsNobody]

17 hours ago, carusoam said:

Well....

That is a good question...

The Pilot has a button/valve under his thumb....

If that button has been removed and replaced with the electric switch powered valve on the panel...

That could make it the pilot’s switch. And pilot’s valve... 

I reviewed the drawing that Ross posted and didn’t quite get the reason why it was called the pilot valve...

I think I do now...

Best regards,

-a-

I have the electric solenoid installed.  The yoke switch does same as the old yoke thumb button, but instead of holding it is “off” or on (PC) based on switch position.  The solenoid is “working” when you have PC in off position as it has an electric input to close the valve...just like your thumb.  YOU STILL HAVE THE PC control.  Mine in my ‘66 is below (pilot side) window access below the hydraulic fluid reservoir.  I haven’t seen it, but I know it is there.  When it dies I will replace with the unit that is married to Turn Coordinator.  (TC-100)

Edited July 19, 2018 by MyNameIsNobody

[MyNameIsNobody]

11 hours ago, mbiggs said:

Now I am confused! I can not find a pilot valve anywhere in my PC system (65C with electric yoke button mod). Does the electric yoke switch with solenoid (part number 4085) replace the pneumatic pilot valve?

I guess you couldn’t find it...

Answer is NO.  It is in there somewhere.

[David Lloyd]

16 hours ago, carusoam said:

Well....

That is a good question...

The Pilot has a button/valve under his thumb....

If that button has been removed and replaced with the electric switch powered valve on the panel...

That could make it the pilot’s switch. And pilot’s valve... 

I reviewed the drawing that Ross posted and didn’t quite get the reason why it was called the pilot valve...

I think I do now...

Best regards,

-a-

Unclear why Mooney chose to call the little hidden box with tubing run to and from it a pilot valve.  In the pneumatics industry it is called a piloted valve, sometimes a pilot operated valve, a valve whose spool is shifted by an external means (the little pushbutton valve on the yoke).  And Mooney even added to the confusion by misspelling the caption in the picture "Pivot Valve".