Matronics Email Lists :: View topic - B-nut loosening on oil fittings?

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

B-nut loosening on oil fittings?

Matronics Email Lists Forum Index -> Europa-List

View previous topic :: View next topic

Author Message

rparigoris

Joined: 24 Nov 2009
Posts: 796

Posted: Wed Dec 23, 2020 6:43 pm Post subject: B-nut loosening on oil fittings?

Hi Group Has anyone ever had a B-nut loosen on a Rotax oil system? I have some external retaining rings I can push onto the radiator and oil tank B-nuts and safety wire, but wondering if I need or want to do so? Thx. Ron P.

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

Duncan McFadyean

Joined: 18 Jan 2011
Posts: 220

Posted: Thu Dec 24, 2020 1:33 am Post subject: B-nut loosening on oil fittings?

I've had them loosen enough not to be obviously loose (still seemed tight) but enough to enable air to be sucked in giving a jumpy oil pressure gauge reading (needle repeatedly flicking down to about 5 psi below normal indication; a mechanical gauge used to check this was yet more violent). I think the leakage had more to do with the machining accuracy of the ball fitting rather than the complete tightness of the nut per se.

I've seen others' that were loose, but may not have been tightened sufficiently after intervention (thermostat fitting).



Duncan McF.



 	  Quote: 	
		   On 24 December 2020 at 02:43 rparigoris <rparigor(at)hotmail.com> wrote:

 

 

 

 

 Hi Group Has anyone ever had a B-nut loosen on a Rotax oil system? I have some external retaining rings I can push onto the radiator and oil tank B-nuts and safety wire, but wondering if I need or want to do so? Thx. Ron P.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=499789#499789

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Thu Dec 24, 2020 7:18 am Post subject: B-nut loosening on oil fittings?

Ron,

I have found the nuts on the cooler not completely tight on some occasions doing pre engine run checks on new aircraft.  

Normally the client has failed to seat the cup and fitting well before attempting to tighten and then snug the fitting, as they are concerned about overtightening on the tank and cooler which can damage a fitting.



The oil cooler tightening is a bit of a concern as the hoses are pulling during the tightening sequence in some instances.  To make the whole process easier in the shop I would slack the oil line, position the fitting and hand tighten the nut.  Wiggle the line and tighten some more.  Difficult to do in place.  I drop my oil coolers as far as possible and do not use the 90 degree fitting supplied by Europa.  I order a straight fitting for nearly all my clients to assure an easy and CFC standard fit.  By lowering the cooler well below the duct top, I find getting to my nuts much easier and is a great help during servicing and inspection as the fitting can be tightened and inspected below the duct metal top quite easily.



Personally, I cut the handles of the wrenches needed to fit the cooler fittings so one can get to the fitting easily and properly snug the nut.  Special tools for a special airplane I guess.



Once tight, wiggle the hose to assure there is little to no torque on the fitting and check the fitting again.

Apply torque seal paint as an indicator for inspection.  I find the nuts on my coolers do not loosen.



Note:

The 90 degree fitting supplied in conjunction with hose routing can cause a loosening torque that can pull the fitting.  If truly concerned there are remedies to help safety the nut.  

	1.  The nut cannot be drilled for safety wire so one can use a Breeze clamp shaped to the nut flanges and tighten the clamp.  Then safety the clamp screw.  	Use the clamp worm fitting as an anchor then to safety to the other fitting.  This is extremely difficult to do after the duct is installed.

	2.  Loctite can be used on the threads also.  



Personally, because I use the straight fittings on my duct, I have found no reason to use safety wire or Loctite.  My torque seal paint has revealed no movement and on my 5 year removal of the duct and flush of my coolers, all goes back together well.



I do use the "Breeze Clamp method" on my oil tank however as I use leaded AVGas for fuel mostly and every annual, I pull and clean my tank to see the performance of my lead purging.  I also have had my return line loosen one time in 15 years on the tank due to engine start and running vibration I suspect.  Post mortem revealed an oil line a bit too tightly bent so as to push on my fitting.  I was suspect of my fittings may be leaking so I "Breeze clamped them.  Come to find out the oil filler cap seal was poor.  (Try to find just that rubber gasket!  Rotax wants you to buy a new cap!)



So to service my tank, clamps get loosened and refitted at least once a year and the belts and suspenders clamp and safety wire is a confidence builder for me.  



Trust but verify as they say.



Best Regards,

Bud Yerly



--

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Europa-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum