Leaky strut that is driving me crazy

[Ronald Cecchi]

Hello all,
I have a 260Turbo with a strut that is driving me crazy. The gear had been rebuilt and the struts re-chromed before I bought the airplane. But I have a strut that keeps leaking and I am not sure why. The seal has been replaced twice. The crazy part is that it is inconsistent when it leaks. After the last seal replacement it still seemed to have a slow leak for a while then it stabillized slightly below the normal level. It seemed fine, then over the winter I went a while without flying it and went over to check the airplane. I found a puddle of oil and a flat strut. We pumped up the strut and it seemed to hold. Did a few landings and it perhaps dropped a little but not too bad. Sat in the hangar for a couple of weeks and came back and it was still at the same level. Flew the plane, then since my a/p was there that day decided to pump it up a little more just to have a little extra. Moved it back to the hanger, pushed it in, put my stuff away and before I left I noticed it was way down again! No oil other than the one time, but way down. Trying to decide where to go next with it. Any idea from you experts with more Comanche experience than myself? Thanks!
Ron

[Andrew Foster]

Could it be the Schrader valve leaking ?

[LeWayne Garrison]

You may have already done this, but there is a packing at the top of the strut also. Commonly the botttom packing is changed but the top is left as it is a little bit tougher to get to. Check to see if that was replaced as well.

[William Hughes]

If the oil is getting out then there is a leak in the lower seal or perhaps a crack some metal. The lower seal is an O-ring and there will always be a little bit of leakage over time as the strut moves back and forth and leaves oil behind on the shaft. This is small though. Usually the oil goes black and becomes sludgy long before it all leaks out in normal service.

If you are losing pressure but no oil then there is a leak in the top - most likely the valve, but it could be other more costly items.

If the oil leaked out then that oil needs to be replaced as pumping up the strut will work but the oleo is now mostly a spring. It will also be more sensitive to temperature changes which can look deceptively like leaks...

[Brian Fogleman]

I had the same problem. Would leak down intermittent. Try the product Glanville strut seal from aircraft spruce. also buy the strut service jug with the hose that screws on the valve. Once you add the strut seal product to some fluid as per the instructions, you can cycle the strut up and down by hand and fill and empty the strut of fluid. This will assure the proper amount of fluid in the strut and allow you to put the "treated" fluid in. Then charge with nitrogen.

After doing this to my own, never had another leak down.

Good luck!