lubing your oleo (which is not a porn title)

twdeckard

twdeckard

Pre-takeoff checklist
Joined
Jun 7, 2008
Messages
268
Location
Minneapolis
Display Name
Display name:
twdeckard
I recently had a flat nose strut in a C182. Our club practice is to fastidiously wipe them down when we turn them in, however, I had been flying all week and dogfighting mayflies and its a safe bet the crusted bug carcasses sliced the gasket.

This is a question about the best way to keep them clean, or a concern about how not too. We use Magic Bug Juice all over the airplane, even on the plexi. It is a mysterious formula of water/dishwashing liquid and, yes, a little ammonia.

While being consoled on my mechanical misfortune someone offered that WD40 was the most appropriate way to clean the exposed part of the strut. I am worried that while bugs and rubber gaskets are actually not that far apart on the periodic table (give or take a few million years) the only things that would be expecting ammonia would be on the moon Titan.

We aren't making self fulfilling prophecies by slathering these things down with windex are we? Is there a better formula?

Thanks!
Todd
 
It probably didn't slice "the gasket" but small pieces of it may have gotten under the o-ring seal at the bottom of the strut.

I generally recommend that you keep a small bottle of hydraulic fluid (5606) to dampen down a rag, get the tail as low as it will go, and wipe the strut clean. 5606 is a pretty good bug solvent, but I wouldn't use it on paint or plexi.

Jim
 
Ditto on the 5606. My Cherokee had a wicked case of strut 'stiction' (would not compress on landing) when I bought it many years ago. I have been using 5606 to wipe the struts and keep them clean and that problem went away after a few months, never to return (hooray !).


weirdjim said:
It probably didn't slice "the gasket" but small pieces of it may have gotten under the o-ring seal at the bottom of the strut.

I generally recommend that you keep a small bottle of hydraulic fluid (5606) to dampen down a rag, get the tail as low as it will go, and wipe the strut clean. 5606 is a pretty good bug solvent, but I wouldn't use it on paint or plexi.

Jim
Click to expand...
 
Thanks for this! As I would have to evangelize this to the other club members -- is there any reason that the pledge and ammonia solution might be actually harmful to the o-ring. I wince a bit when we spritz it on the windshield but it doesn't seem any the worse for wear. It must mean that there is very little ammonia in it?

Is there an advantage to using the hydraulic fluid beyond cleaning? My WD40 advocate claimed that the lubrication was also helpful to extend the life of the o-ring assembly.
 
twdeckard said:
Thanks for this! As I would have to evangelize this to the other club members -- is there any reason that the pledge and ammonia solution might be actually harmful to the o-ring. I wince a bit when we spritz it on the windshield but it doesn't seem any the worse for wear. It must mean that there is very little ammonia in it?

Is there an advantage to using the hydraulic fluid beyond cleaning? My WD40 advocate claimed that the lubrication was also helpful to extend the life of the o-ring assembly.
Click to expand...

The hydraulic fluid (5606) is what's already inside the oleo and the O-ring seal is compatible with it. The seal might not be compatible with the solvents in WD-40 or with ammonia.

I used to make my living rebuilding air and hydraulic brake valves, compressors, and boosters. The boosters used in vehicles are designed to work with DOT-3 brake fluid. Sometimes some guy's brakes would get low on fluid and he'd add motor oil because that's all he had handy, and it's all the same anyway, right? Well, we made good profit overhauling the whole system when the rubber bits all swelled up and came apart. They were designed for use with DOT-3 fluid, a vegetable-based alcohol-type oil, not a petroleum product, and couldn't handle the wrong stuff.

There are numerous O-ring compounds, for different purposes and temperature ranges and fluids and pressures. The sad thing here is that the typical nose oleo seal is the MS-28775 series, an old compound that should have been superseded long ago by the newer space-age stuff. The newer stuff won't harden and lose its elasticity with age and exposure to 5606. It won't shrink in the cold and let the fluid out. It won't grab the oleo strut barrel when it shrinks and get rolled over and torn in its groove. But since the parts catalog says MS-28775, that's what we gotta use to stay legal.

So until we're able to use a much better compound in oleos, better be careful what you go spritzing it with. If yours is a bit weepy, you can add a bit of Granville Strut Seal to the strut's oil, which swells the O-ring (probably by attacking it chemically, of course).


Dan
 
You can wash that nose strut with any thing you like, it is hard chrome, to make a truck bumper envious. the "O" ring is not going to get any thing on it from the outside, it is behind a scraper ring and has pressure on it from the inside and zero pressure from the out side.

Plus it has 2 teflon back up rings 1 on each side of it to protect it.

Just don't scratch the strut chrome plating.

the bug didn't do any thing to cause the strut to colapse. the scraper ring will take the bugs off like a razor blade. they won't get anywhere near the "O" ring.

a coating of oil of any kind will just attract dust and cause wear on the scraper ring and chrome.

add 4 oz of Grandvill strut seal and call me next week.
 
Last edited:
weirdjim said:
It probably didn't slice "the gasket" but small pieces of it may have gotten under the o-ring seal at the bottom of the strut.

I generally recommend that you keep a small bottle of hydraulic fluid (5606) to dampen down a rag, get the tail as low as it will go, and wipe the strut clean. 5606 is a pretty good bug solvent, but I wouldn't use it on paint or plexi.

Jim
Click to expand...
I also do as Jim mentions
 
Tom-D said:
Plus it has 2 teflon back up rings 1 on each side of it to protect it.
Click to expand...

How could it have teflon backup rings? That airplane was designed WAY before teflon was invented.

Not arguing, just curious. I've never seen one with teflon inside.

Jim
 
weirdjim said:
How could it have teflon backup rings? That airplane was designed WAY before teflon was invented.

Not arguing, just curious. I've never seen one with teflon inside.

Jim
Click to expand...

When exactly do you think teflon was invented? Follow that with an explanation of when the 182 was designed.

Now edit your reply.
 
Clark1961 said:
When exactly do you think teflon was invented? Follow that with an explanation of when the 182 was designed.

Now edit your reply.
Click to expand...


Jeez, I only asked a question politely. And evidently my understanding of teflon history is flawed. I only said that **I** hadn't seen teflon backup rings in a 182 nose gear strut, not that they weren't there, and I asked for clarification.

Thanks for the emphatic clarification, I guess.

BTW, the 182 service manual calls them "teflon shims" and are only used to take up excessive clearance if any exists (page 5-22).

Jim
 
weirdjim said:
Jeez, I only asked a question politely. And evidently my understanding of teflon history is flawed. I only said that **I** hadn't seen teflon backup rings in a 182 nose gear strut, not that they weren't there, and I asked for clarification.

Jim
Click to expand...

They're there, alright. But they don't contact the strut barrel in any significant way. The nylon scraper ring does that, in order to scrape off debris that would otherwise get under the O-ring and maybe score it.

But I've seen those scraper rings chewed up by grit that sticks to the barrel, since 5606 will get gummy if it just sits there and dries out and sand will then stick to it, and then the scraper doesn't stop all the junk from reaching the O-ring. The nylon can also shrink some with age and start grabbing the strut barrel and make it stick in the oleo, and I also came across a barrel boss in which the O-ring groove was a little too shallow so that the O-ring itself gripped the barrel too tightly and made it stick. The Cessna single retractables have the squat switch on the nose scissors and a sticky barrel can keep the switch closed long after touchdown. Not good.

Dan
 
weirdjim said:
Jeez, I only asked a question politely. And evidently my understanding of teflon history is flawed. I only said that **I** hadn't seen teflon backup rings in a 182 nose gear strut, not that they weren't there, and I asked for clarification.

Thanks for the emphatic clarification, I guess.

BTW, the 182 service manual calls them "teflon shims" and are only used to take up excessive clearance if any exists (page 5-22).

Jim
Click to expand...

No, Jim, you weren't polite at all. You made a false claim which attempted to denigrate the poster to whom you were responding. In other words you most certainly didn't convey that you "only said that **I** hadn't seen teflon" since you claimed that teflon didn't exist when the 182 was designed.

I'm sorry that you were unable to admit your obvious culpability and correct your error. I'll certainly keep your uncorrected false claim in mind in any future posts you may make.
 
Clark1961 said:
No, Jim, you weren't polite at all. You made a false claim which attempted to denigrate the poster to whom you were responding. In other words you most certainly didn't convey that you "only said that **I** hadn't seen teflon" since you claimed that teflon didn't exist when the 182 was designed.

I'm sorry that you were unable to admit your obvious culpability and correct your error. I'll certainly keep your uncorrected false claim in mind in any future posts you may make.
Click to expand...


You've got all the personality traits and I'm sure you will make a GREAT FAA inspector.

Jim
 
I'm with the 5606 crew. I like to wipe the strut with a rag that is dampened with 5606. The thing that I see once in a while, is when an airplane is not flown for a long time, and the strut dries out, then when the strut is compressed, as in landing, the o'ring rolls and get's twisted. I've changed plenty of them out. A nice film of 5606 will help keep that from happening. I also agree that nothing is going to get past the scraper ring, unless the scraper ring is shot, and I've seen that before too, especially if the plane is not flown a lot. That said, a strut that is getting plenty of exercise shouldn't be getting dry enough to mess up the o'rings..
 
weirdjim said:
You've got all the personality traits and I'm sure you will make a GREAT FAA inspector.

Jim
Click to expand...

+1

RE: Lubing the strut...I don't and have never had a problem. It gets serviced every annual and that's it.

Of course, I fly regularly but, then again, I believe the OP said he was dealing with a club plane...can't imagine it doesn't get regularly lubricated by the act of flying (actually, the act of landing).

Oh, and my strut has quite a few scratches also.
 
For every ones info,,,,,, the scraper ring is a bronz ring that has been split to take tention on the strut as it slides alone the chrome portion of the strut. scdrapping away every thing as it does.

It is held in place by a snap ring enbeded into the exterior cylinder that forms the strut itself, which holds it against the teflon back up ring which supports the "O" ring.

placing oil on the strut, (oil of any kind) and allowing it to gather dust makes a pretty good grinding compound, which wears away the scrapper ring and chrome surface of the strut. After the chrome is worn off the strut, and the scrapper ring is worn out all the dust gets to the "O" ring and it starts to leak.

Now the pilot/owner wants it fixed, and the repair is a new strut, my price around 2 grand, if you can find one. If you got a early square tailed 150/172/182 they take a long strut, and there aint any any where. you are now into trying to get it rechromed, baked and treated if you can find a plating shop who will touch any aircraft part.

For all thoes of you who put oil on the strut we A&Ps love you, keep it up we need the work.

Keep your struts clean and dry, the "O" ring will get lubed from the inner side.
 
Dan Thomas said:
They're there, alright. But they don't contact the strut barrel in any significant way. The nylon scraper ring does that, in order to scrape off debris that would otherwise get under the O-ring and maybe score it.
Dan
Click to expand...

every repack kit that I have ever installed has a bronz scrapper ring.

there are 2 teflon rings that support the "O" ring, they are shapped like [(O)], they are not scrappers. they are commonally known as "back up" rings that support the sealing "O" ring.
 
Tom-D said:
... you are now into trying to get it rechromed, baked and treated if you can find a plating shop who will touch any aircraft part.
Click to expand...
airplane part? Nah, I just need this hydraulic steering stabilizer shaft rechromed. :D not that I would EVER condone departing from the regulations! :no:
 
Hiperbiper said:
What is this "Nose Gear" of which you fella's speak of???:wink2:


Chris:eek:
Click to expand...
For some reason, some aircraft seem to have the tailwheel installed on the wrong end.

Dunno if this is due to a design flaw or an assembly error. But apparently, this causes a lot of problems when it happens.
 
What about using LPS2?
 
Tom-D said:
every repack kit that I have ever installed has a bronz scrapper ring.

there are 2 teflon rings that support the "O" ring, they are shapped like [(O)], they are not scrappers. they are commonally known as "back up" rings that support the sealing "O" ring.
Click to expand...


I've been doing these things for 14 years and haven't seen a bronze scraper ring yet. All are nylon. All bought from Cessna.

Dan
 
Old thread, I know.
Notes:
-Don't let the hydraulic fluid stay on your tire. It WILL ruin it. The good news is that the tire was about done anyway...
-If the chrome cylinder is done, mine is pitted, you can get it rechromed. The new part is $2950, used are almost impossible to find (found one in Norway), and it IS possible to rechrome the old one. $575 including pressing it out, rechroming, and pressing it back in.

Jim
 
You must log in or register to reply here.
Back
Top