Nose Strut O-Ring Was Bad...

[Jay Honeck]

Last week, in -22 temperatures, our nose gear drooped all the way to
the stop. Later, we were able to put some down pressure on the
stabilator (in the hangar) and bring it back up a couple of inches,
but made plans to have our A&P look at it.

Yesterday, since he wasn't coming in the shop till afternoon, we
decided to go flying first. My landing in Oskaloosa, IA (KOOA) was
gingerly -- a text book soft field landing, with the nose gear staying
high in the air till almost stopped. The strut stayed up around three
inches all the way to parking. The temperature was about 5 above
zero, and I thought that perhaps this had been a transient problem
that had "fixed itself". (We always hope, no? :-)

Not. Mary's landing back in Iowa City was fine, but the strut again
collapsed to the stop -- so we taxied straight to the shop. My A&P
told me that he could "service" it (basically, add air), but after
some discussion we decided to replace the seals in the strut. He
said that the O-rings were likely old (we hadn't replaced them in the
5 years we've owned Atlas), stiff, and perhaps "rolled", so that even
though lubricating the strut and adding air might do the trick for a
while, it would be a stop-gap measure, at best.

I helped him do it, and it took about an hour. (Of course, he's done
it a million times -- the job would have taken me all day, with
instructions, and I might have killed myself doing it.) But now, the
strut is sitting tall again, with new fluids, O-rings, and air
pressure.

Total: $65. Not bad at all, in aviation terms...

He says that it's SOP to apply brake fluid to the struts of the DC-9s
he services (at his day job) every, single time they park. It's
messy, as a result, but their strut seals rarely need to be replaced.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[[email protected]]

On Feb 8, 8:32 am, "Jay Honeck" > wrote:
> Last week, in -22 temperatures, our nose gear drooped all the way to
> the stop. Later, we were able to put some down pressure on the
> stabilator (in the hangar) and bring it back up a couple of inches,
> but made plans to have our A&P look at it.
>
> Yesterday, since he wasn't coming in the shop till afternoon, we
> decided to go flying first. My landing in Oskaloosa, IA (KOOA) was
> gingerly -- a text book soft field landing, with the nose gear staying
> high in the air till almost stopped. The strut stayed up around three
> inches all the way to parking. The temperature was about 5 above
> zero, and I thought that perhaps this had been a transient problem
> that had "fixed itself". (We always hope, no? :-)
>
> Not. Mary's landing back in Iowa City was fine, but the strut again
> collapsed to the stop -- so we taxied straight to the shop. My A&P
> told me that he could "service" it (basically, add air), but after
> some discussion we decided to replace the seals in the strut. He
> said that the O-rings were likely old (we hadn't replaced them in the
> 5 years we've owned Atlas), stiff, and perhaps "rolled", so that even
> though lubricating the strut and adding air might do the trick for a
> while, it would be a stop-gap measure, at best.
>
> I helped him do it, and it took about an hour. (Of course, he's done
> it a million times -- the job would have taken me all day, with
> instructions, and I might have killed myself doing it.) But now, the
> strut is sitting tall again, with new fluids, O-rings, and air
> pressure.
>
> Total: $65. Not bad at all, in aviation terms...
>
> He says that it's SOP to apply brake fluid to the struts of the DC-9s
> he services (at his day job) every, single time they park. It's
> messy, as a result, but their strut seals rarely need to be replaced.

Problem there is the attraction of dust, which then fouls the
scraper ring and eventually gets under the O-ring and abrades it. We
keep ours just wiped off.
The cold weather makes the O-rings shrink and grab the strut
barrel, and then they roll in the groove and because their flexibility
is gone in the cold, they suffer spiral fractures. It's good practice
to replace them regularly. Granville Strut Seal added to the fluid
will sometimes help by swelling the ring slightly and making it a bit
softer.
There are far better O-rings out there now. I wish someone
like McFarlane would come up with an STC'd oleo kit that used
fluorosilicone or EPDM or some other advanced compound rings. Tougher
and with a better temperature range. There are "quad" O-rings
available, too, that would do a better job. In cross-section they look
like a four-leaf clover, so there's more contact area on two places
and they are more flexible, too. Double the sealing capacity, and
resistant to rolling.

Dan

[Matt Whiting]

Jay Honeck wrote:

> He says that it's SOP to apply brake fluid to the struts of the DC-9s
> he services (at his day job) every, single time they park. It's
> messy, as a result, but their strut seals rarely need to be replaced.

Interesting as we did just the opposite with exposed cylinders on the
logging equipment I operated many moons ago. Any oil just collected
dust and formed an abrasive slurry that wass very hard on the seals. I
guess most airplanes probably don't pick up that much dirt normally, but
if I operated from a gravel or dirt strip I'd think twice before
oiling the strut cylinder.


Matt

[Kyle Boatright]

> wrote in message
ups.com...
> On Feb 8, 8:32 am, "Jay Honeck" > wrote:
>> Last week, in -22 temperatures, our nose gear drooped all the way to
>> the stop. Later, we were able to put some down pressure on the
>> stabilator (in the hangar) and bring it back up a couple of inches,
>> but made plans to have our A&P look at it.
>>
>> Yesterday, since he wasn't coming in the shop till afternoon, we
>> decided to go flying first. My landing in Oskaloosa, IA (KOOA) was
>> gingerly -- a text book soft field landing, with the nose gear staying
>> high in the air till almost stopped. The strut stayed up around three
>> inches all the way to parking. The temperature was about 5 above
>> zero, and I thought that perhaps this had been a transient problem
>> that had "fixed itself". (We always hope, no? :-)
>>
>> Not. Mary's landing back in Iowa City was fine, but the strut again
>> collapsed to the stop -- so we taxied straight to the shop. My A&P
>> told me that he could "service" it (basically, add air), but after
>> some discussion we decided to replace the seals in the strut. He
>> said that the O-rings were likely old (we hadn't replaced them in the
>> 5 years we've owned Atlas), stiff, and perhaps "rolled", so that even
>> though lubricating the strut and adding air might do the trick for a
>> while, it would be a stop-gap measure, at best.
>>
>> I helped him do it, and it took about an hour. (Of course, he's done
>> it a million times -- the job would have taken me all day, with
>> instructions, and I might have killed myself doing it.) But now, the
>> strut is sitting tall again, with new fluids, O-rings, and air
>> pressure.
>>
>> Total: $65. Not bad at all, in aviation terms...
>>
>> He says that it's SOP to apply brake fluid to the struts of the DC-9s
>> he services (at his day job) every, single time they park. It's
>> messy, as a result, but their strut seals rarely need to be replaced.
>
> Problem there is the attraction of dust, which then fouls the
> scraper ring and eventually gets under the O-ring and abrades it. We
> keep ours just wiped off.
> The cold weather makes the O-rings shrink and grab the strut
> barrel, and then they roll in the groove and because their flexibility
> is gone in the cold, they suffer spiral fractures. It's good practice
> to replace them regularly. Granville Strut Seal added to the fluid
> will sometimes help by swelling the ring slightly and making it a bit
> softer.
> There are far better O-rings out there now. I wish someone
> like McFarlane would come up with an STC'd oleo kit that used
> fluorosilicone or EPDM or some other advanced compound rings. Tougher
> and with a better temperature range. There are "quad" O-rings
> available, too, that would do a better job. In cross-section they look
> like a four-leaf clover, so there's more contact area on two places
> and they are more flexible, too. Double the sealing capacity, and
> resistant to rolling.
>
> Dan

If I had a certified airplane and knew of better O-rings out there, it
wouldn't surprise me if the hangar elves (elfs?) mysteriously installed a
set of the improved O-rings. I, of course, would never do such a thing on a
certified airplane, but mysterious things sometimes happen behind closed
hangar doors.

Fortunately, I have an experimental aircraft and can install whatever
O-rings I want...

KB

[Mike Spera]

> .lots of stuff snipped
> There are far better O-rings out there now. I wish someone
> like McFarlane would come up with an STC'd oleo kit that used
> fluorosilicone or EPDM or some other advanced compound rings. Tougher
> and with a better temperature range. There are "quad" O-rings
> available, too, that would do a better job. In cross-section they look
> like a four-leaf clover, so there's more contact area on two places
> and they are more flexible, too. Double the sealing capacity, and
> resistant to rolling.
>
> Dan
>

Cherokee strut seals are quad 0-rings (or at least they are square-ish).
Typically they last 20+ years and start to leak fluid. That can continue
for many years. When I replaced all mine, the nose immediately started
leaking. Took 2-4 days to deflate. After a couple of ounces of
Granville, it stopped. Not sure if we bunged up the install or the ring
had a defect. Still up after a year.

Oddly, I thought the new seals would make the struts move more freely.
That was not the case with mine. They still have a healthy amount of
"stick".

Good luck,
Mike

[Dave[_3_]]

Well..

That's .065 AMU's....

I have always found that having the "naughts" in FRONT of the real
numbers was better than having the "naughts' (0's) AFTER the real
numbers...

:)

Dave


On 8 Feb 2007 07:32:25 -0800, "Jay Honeck" > wrote:

>Last week, in -22 temperatures, our nose gear drooped all the way to
>the stop. Later, we were able to put some down pressure on the
>stabilator (in the hangar) and bring it back up a couple of inches,
>but made plans to have our A&P look at it.
>
>Yesterday, since he wasn't coming in the shop till afternoon, we
>decided to go flying first. My landing in Oskaloosa, IA (KOOA) was
>gingerly -- a text book soft field landing, with the nose gear staying
>high in the air till almost stopped. The strut stayed up around three
>inches all the way to parking. The temperature was about 5 above
>zero, and I thought that perhaps this had been a transient problem
>that had "fixed itself". (We always hope, no? :-)
>
>Not. Mary's landing back in Iowa City was fine, but the strut again
>collapsed to the stop -- so we taxied straight to the shop. My A&P
>told me that he could "service" it (basically, add air), but after
>some discussion we decided to replace the seals in the strut. He
>said that the O-rings were likely old (we hadn't replaced them in the
>5 years we've owned Atlas), stiff, and perhaps "rolled", so that even
>though lubricating the strut and adding air might do the trick for a
>while, it would be a stop-gap measure, at best.
>
>I helped him do it, and it took about an hour. (Of course, he's done
>it a million times -- the job would have taken me all day, with
>instructions, and I might have killed myself doing it.) But now, the
>strut is sitting tall again, with new fluids, O-rings, and air
>pressure.
>
>Total: $65. Not bad at all, in aviation terms...
>
>He says that it's SOP to apply brake fluid to the struts of the DC-9s
>he services (at his day job) every, single time they park. It's
>messy, as a result, but their strut seals rarely need to be replaced.

[Ron Rosenfeld]

On 8 Feb 2007 07:32:25 -0800, "Jay Honeck" > wrote:

>I helped him do it, and it took about an hour.

And if you hadn't helped him, it might have taken, what? a half-hour?
:-))


--ron

[Jay Honeck]

> And if you hadn't helped him, it might have taken, what? a half-hour?
> :-))

Probably.

Actually, as I've gotten more experience (I'm into my 9th year of
aircraft ownership now -- dang, how did THAT happen?) I've grown more
competent at helping my A&P.

Mostly that means I now know when to stay the hell out of his way...

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Matt Barrow]

"Jay Honeck" > wrote in message
ups.com...
>> And if you hadn't helped him, it might have taken, what? a half-hour?
>> :-))
>
> Probably.
>
> Actually, as I've gotten more experience (I'm into my 9th year of
> aircraft ownership now -- dang, how did THAT happen?) I've grown more
> competent at helping my A&P.
>
> Mostly that means I now know when to stay the hell out of his way...
>
> ;-)

Mostly that means always. :~o

[Ron Rosenfeld]

On 9 Feb 2007 19:36:01 -0800, "Jay Honeck" > wrote:

>> And if you hadn't helped him, it might have taken, what? a half-hour?
>> :-))
>
>Probably.
>
>Actually, as I've gotten more experience (I'm into my 9th year of
>aircraft ownership now -- dang, how did THAT happen?) I've grown more
>competent at helping my A&P.
>
>Mostly that means I now know when to stay the hell out of his way...
>
>;-)

I suppose it's a matter of interest and skills in doing that sort of thing.
I've had my airplane since 1976 and try to stay close when it's being
worked on. So I've seen a lot and retained some. But I've not been
interested in picking up tools.

I've changed a tire tube once; and I've also replaced a landing light. I
won't do either again unless the necessity presents itself as it did those
times.



--ron

[Jay Honeck]

> So I've seen a lot and retained some. But I've not been
> interested in picking up tools.

I like getting dirty, and playing with tools. In my regular life, I
don't get much of a chance (well, other than remodeling the hotel --
but that's a different kind of tools!) to play with cars or
motorcycles anymore, so when I get a chance to do an owner-assisted
annual, I jump at it.

I've learned a LOT along the way. After doing it nine years in a row,
I pretty much know the inspection by heart. It sure makes things
easier.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Tri-Pacer]

> motorcycles anymore, so when I get a chance to do an owner-assisted
> annual, I jump at it.
>


I LOVE owner assisted annuals. I just finished one on an Ercoupe. The owner
was crying about how hard it was to get the floor boards out, and how much
his back hurt him.

I simply reminded him that it was "an OWNER assisted annual" and continued
on with my compression check.

Cheers:

Paul
N1431A
(A&P IA)

[bdl]

On Feb 8, 9:32 am, "Jay Honeck" > wrote:
>
> Total: $65. Not bad at all, in aviation terms...
>

We just did our's in our Archer last Friday. After constantly putting
nitrogen in the nose strut, we arranged for our A&P to replace the
seals. We filled it up again and one of my partner and I took off
runway 16 at 1H0 to go over to our A&P at KSUS.

Right after lift off I hear this "bang", not loud, but not something
you want to hear in a airplane. Went around the traffic pattern,
didnt' see that we lost anything on the runway, so we decided to head
over to SUS. Did a low approach for the tower, and they confirmed
that we still had a nose gear. Landed, and it was down to the
stops. Figure'd the bang was either the nose strut fully extending,
or a piece of ice that he must have hit on the runway during the
takeoff roll.

An hour later and everything is great.
-- Brian

[NW_Pilot]

"Mike Spera" > wrote in message
link.net...
>
>> .lots of stuff snipped
>> There are far better O-rings out there now. I wish someone
>> like McFarlane would come up with an STC'd oleo kit that used
>> fluorosilicone or EPDM or some other advanced compound rings. Tougher
>> and with a better temperature range. There are "quad" O-rings
>> available, too, that would do a better job. In cross-section they look
>> like a four-leaf clover, so there's more contact area on two places
>> and they are more flexible, too. Double the sealing capacity, and
>> resistant to rolling.
>>
>> Dan
>>
>
> Cherokee strut seals are quad 0-rings (or at least they are square-ish).
> Typically they last 20+ years and start to leak fluid. That can continue
> for many years. When I replaced all mine, the nose immediately started
> leaking. Took 2-4 days to deflate. After a couple of ounces of Granville,
> it stopped. Not sure if we bunged up the install or the ring had a defect.
> Still up after a year.
>
> Oddly, I thought the new seals would make the struts move more freely.
> That was not the case with mine. They still have a healthy amount of
> "stick".
>
> Good luck,
> Mike

I hate that in a piper when a strut sticks and 1/2 your landing roll is lop
sided!

[NW_Pilot]

"Jay Honeck" > wrote in message
ups.com...
>> And if you hadn't helped him, it might have taken, what? a half-hour?
>> :-))
>
> Probably.
>
> Actually, as I've gotten more experience (I'm into my 9th year of
> aircraft ownership now -- dang, how did THAT happen?) I've grown more
> competent at helping my A&P.
>
> Mostly that means I now know when to stay the hell out of his way...
>
> ;-)
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>


I myself either help with or watch everything when my plane is being worked
on! It's not my wrenches life up there it's mine and my family! There are
some wrenches out there that you kind of wonder who reminded them to breathe
when they woke up! Jay, I admire your persistence in helping and being
involved in the maintenance of your bird will make your flying safer for
many years and you also learn new skills. I Wish a lot of other
pilots/owners would do the same....even if it takes longer to help it's
worth every penny!

[NW_Pilot]

"Tri-Pacer" > wrote in message
. ..
>> motorcycles anymore, so when I get a chance to do an owner-assisted
>> annual, I jump at it.
>>
>
>
> I LOVE owner assisted annuals. I just finished one on an Ercoupe. The
> owner was crying about how hard it was to get the floor boards out, and
> how much his back hurt him.
>
> I simply reminded him that it was "an OWNER assisted annual" and continued
> on with my compression check.
>
> Cheers:
>
> Paul
> N1431A
> (A&P IA)
>

And if I was him or the one paying you I would have told you to take a long
walk with that answer!!!!

[nrp]

> > Oddly, I thought the new seals would make the struts move more freely.
> > That was not the case with mine. They still have a healthy amount of
> > "stick".

Try smearing STP (Moto-Honey to some.....) on the exposed strut. It
helps elastomeric seals break in - even to the point that it will
migrate into the strut interior.

Don't laugh - I have done this on hydraulic actuators to temporarily
reduce the rod friction in a cyclic applications. It was absolutely
amazing what it would do with the effects lasting for maybe an hour or
so. These were actuators that cycled maybe 5 Hz or more. I suspect
the technique may be quite effective in a simple strut application.