Oleo strut serviicing

[martinbguk]

Thanks Steve

[Paul Watts]

Hi Martin,

It is a schrader valve on top of the strut, however you do not air it up to a particular pressure, rather you add air until you reach a certain extension of the strut. I can't remember exactly how much strut should be visible, but there should be a placard attached near the top of the strut that gives the dimension. Unfortunately these placards get lost, destroyed, or become unreadable over the years. It may also be in the pilots manual (I'm not real sure about that). Frankly, about 2 1/2 to 3 inches (6-8 cm) should be real close. I measure the extension by pulling down on the prop, then quickly releasing. After it rebounds I measure the exposed strut. If you have "3 or 4 fingers" of exposed strut, your good! (in my opinion)

The valve is centered right on top of the strut. It has been a long time since I had a nose gear, but I think there really wasn't a problem reaching the valve from either side, & I don't think you have to remove any cowling (again, it's been a long time!)

There are no special tools required, just an air compressor, and a typical tire chuck. The usual shop compressor probably will not put out enough pressure (un-assisted) to extend the strut. You will almost certainly need to tie down the tail so that the strut is fully extended. Then air up the strut with at least 100 PSI. After that, untie the tail & you should find the strut to be "over" inflated. At that point release air (in very short bursts), checking for proper extension (using the above mentioned "rebound" method) between each 'burst'.

It is really a simple procedure, the first time may take a little time, but you will very quickly 'find your groove'.

Good luck!

[Frank Green]

I can get to it by dropping the left side lower cowling top screws. You need an tire chuck which is almost 90 degrees. I made one chuck only and a couple feet of hose then the coupler to keep the coupler out of the way. My hangar compressor tops out at about 120 psi and with the tail tied and fully extended it is about enough when I let it down. I use air but have red silicone O rings which seal a LOT better especially in winter. With black Buna rings in winter I would have to service just about weekly. Now it will go all winter with out service.

[martinbguk]

So it needs looking at reasonably regularly?

[Old3pacer]

I don't usually need to add or subtract except sometimes with large temperature swings. I check it every preflight (3 fingers)

[Glen Geller]

Our experience (five Tri-Pacers) is with the strut fully extended, pressurize to about 130 psi.
We have a high pressure bike pump for that, you get a fair workout but not really too bad.
Then let the nose down, you should be 3-4 fingers of chrome strut showing. You can blip out a bit of air by depressing the valve stem with a long #8 bolt, like 1/4 second at a time, if its a bit too high.
I usually wipe a bit of hydraulic oil on the strut before first flight of the day and after putting plane away, it keeps the wiper and seal cleaner and wetter, and removes dirt and smashed bugs. We usually go ten years between replacing the seals, so I'm confident that is a good practice.

GG

[Frank Green]

I believe back in the day they used a cigarette pack to measure. I also used ti have an original ashtray in the dash.

[Old3pacer]

LOVE the cigarette pack as a measuring tool!!! I still have 2 ash trays in the cabin -- 1 up front on the glareshield, 1 by the right rear window. Going out today to check my nose strut which appears to have let down. We have had pretty wide outside temp swings. There is no puddle of fluid. Would you just add air or nitrogen and assume fluid is there inside?
Thanks for the advice!

[Paul Watts]

LOVE the cigarette pack as a measuring tool!!! I still have 2 ash trays in the cabin -- 1 up front on the glareshield, 1 by the right rear window. Going out today to check my nose strut which appears to have let down. We have had pretty wide outside temp swings. There is no puddle of fluid. Would you just add air or nitrogen and assume fluid is there inside?
Thanks for the advice!

I have had fluid leaks in the past, and it was always obvious! Traces of red fluid on the strut and lower cowl stand out clearly.

[pmanton]

Has anyone confirmed what the actual pressure is when the struts at 3-1/2?
Paul
Salome, AZ