My strange L3 oleos

[Aerco]

I pulled out my collection of landing gear legs and oleos from my L3B project and set about dismantling these. For some reason I thought of this being some major operation, with visions of seized up, rusted parts refusing to come apart. Looking at the drawings, it did not seem too complicated.

The oleos slid out just fine after some WD40 ("Aircraft Restoration Fluid") and some whacks with a rubber mallet. The spring retainers came off easily. So did the springs. And that's when the easy part stopped:

All 4 legs I have have the packing piece "cup" (part 1-319) brazed into the oleo tube. See the picture.
No doubt about it. I cleaned up the area and there is a 1/16" wide groove filled with brazing material on each one.

I have NO idea how they did this unless they put the packing in afterwards and even then, surely the phenolic upper piston would have been heat damaged. (I had three phenolic ones and one metal - all the phenolic ones are trash now.) There was absolutely no way to get these apart other than with a torch. I even chucked them in the lathe and used a very thin blade to cut into the brass very slightly to make sure I wasn't imagining this, but no - brazed. So I rigged the thing up in the vice, got out the torch and starting heating things up. Naturally, smoke ensues and the packing and oil remnants started to burn. I kept heating gently and at the same time tapping the other end with a hammer until eventually things dislodged, but man, it was a messy, horrible job; oil splattering everywhere and flames shooting all over the place! Each time I whacked the leg, oil remnants got blown past the burnt out packing and ignited, spewing flame.

Good news is, it all came apart eventually and nothing is damaged, except the phenolic pistons, which would have been thrown out anyway. I am still baffled by how they did this and nobody at the L3 group seems to have ever seen this either.

[Paul Agaliotis]

Peter,
The piston is inside the tube under the stuffer plate. The stuffer is brazed to the top of the tube, on top of this is where the rope packing will go. The top stuffer piece pushes down on the packing to seal the shaft as a function of the taxi spring compression when assembled.
If you need to remove the piston, I wouldn't unless required, push the piston to the bottom of the tube and heat the brazed area with a torch. As the braze melts pull the shaft quickly to the top to pop out the stuffer. Be prepared for fire and smoke.
Paul

[DELCOM]

Wasnt there an AD out for the pistons that were phoenolic, to be replaced with aluminum, so as not to have to install the snare cables? The thought was that if the piston was to fail the oleo would slide apart after takeoff? You need to look carefully and see if your pistons are indeed aluminum.My memory is at best vauge.
I will look again for the AD

Del

[Aerco]

Peter,
The piston is inside the tube under the stuffer plate. The stuffer is brazed to the top of the tube, on top of this is where the rope packing will go. The top stuffer piece pushes down on the packing to seal the shaft as a function of the taxi spring compression when assembled.
If you need to remove the piston, I wouldn't unless required, push the piston to the bottom of the tube and heat the brazed area with a torch. As the braze melts pull the shaft quickly to the top to pop out the stuffer. Be prepared for fire and smoke.
Paul

Three out of four legs had the phenolic piston, so yes, I had to un-braze everything. And yes, there was lots of smoke and flames!

[Aerco]

Wasnt there an AD out for the pistons that were phoenolic, to be replaced with aluminum, so as not to have to install the snare cables? The thought was that if the piston was to fail the oleo would slide apart after takeoff? You need to look carefully and see if your pistons are indeed aluminum.My memory is at best vauge.
I will look again for the AD

Del

When you find details, please let me know - I need to find out about installing this cable.

[joea]

You are so lucky to be pulling this apart on the bench and not have one of these come apart after takeoff.

We continue to hear of people pulling a strut apart and finding these old illegal pistons in struts and wonder how someone signed off the annual this way...

Great story and even better with photos!

Thanks,

Joe A

[Paul Agaliotis]

The AD doesn't include the Tandem series, but it's a good idea to look any way. There isn't a big problem with the fiber pistons if you keep the oleos serviced. When they get low on fluid the plane comes slamming down on the fluid if under serviced and over stresses the piston. Generally the piston will fail at the anchor pin and break free. Then the strut will hang from the pin until it fails. So, keep the oleo serviced!
My 7AC has the aluminum pistons and the snare installed.
Paul

[Dennis]

Paul,

How long are your snairs from end to end? Did you use 1/8 cable?

Thanks, Dennis

[Paul Agaliotis]

Dennis,
I believe they are about 8in. in length. They are 1/8th cable with a lug for the axle bolt.
Paul

[Dennis]

Thanks Paul

[Dennis]

Thanks Paul