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Possible Pushrod Boot Corrosion: Please Inspect

Luke D

Luke D

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Hello Everyone,

A customer recently contacted us to ask if our aileron pushrod boots cause corrosion on the aileron pushrods. He had seen reports from another RV builder that this had happened. He wasn't sure who had supplied the boots in question. We have been selling these boots for around 15 years now, and we've never had any reports of this issue. Does anyone have any first hand accounts of this?

Also, if you have pushrod boots of any kind, you should open them up at every condition inspection and check them for corrosion. If they don't already have it, consider applying a protective coating to prevent corrosion.

Thanks,
Luke
 
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I'm about to start my annual inspection, I'll make a point of getting some pictures to you.
 
Luke D said:
Thanks Jon. Looks like this is already being discussed, and I just missed it.
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Easy to miss considering the volume of posts here. Might be a good idea to include some caution in your installation instructions. These areas should be routinely inspected.
On my Bucker, the boots are safety wired. They were designed this way with flanges to capture the safety wire. Easy to snip, expose, and rewire.
 
JonJay said:
Easy to miss considering the volume of posts here. Might be a good idea to include some caution in your installation instructions. These areas should be routinely inspected.
On my Bucker, the boots are safety wired. They were designed this way with flanges to capture the safety wire. Easy to snip, expose, and rewire.
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Yes, we'll definitely add some safety notes to our instructions. Our boots are similar. We use zip ties that go through a "hem" at the big end and the small end. The boot also includes a separating zipper so it can be removed completely for inspection if desired.

I also wonder if something like the adhesive clear plastic film used to protect the flap leading edges could be helpful here. I'm thinking it could be used as a final protective layer over whatever paint of primer is used initially. Kind of an abrasion protector. Any thoughts?
 
Luke D said:
Yes, we'll definitely add some safety notes to our instructions. Our boots are similar. We use zip ties that go through a "hem" at the big end and the small end. The boot also includes a separating zipper so it can be removed completely for inspection if desired.

I also wonder if something like the adhesive clear plastic film used to protect the flap leading edges could be helpful here. I'm thinking it could be used as a final protective layer over whatever paint of primer is used initially. Kind of an abrasion protector. Any thoughts?
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I don’t have boots on my 6 so just spitballing here.
Is the boot intended to slide on the push rod or attach securely and move with it?
 
JonJay said:
I don’t have boots on my 6 so just spitballing here.
Is the boot intended to slide on the push rod or attach securely and move with it?
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Ours are designed be secured around the pushrod with enough tension that they do not slide. You shift the stick to the travel limit and then secure the boot in such a way that the boot does not move on the tube, but also can not limit travel. When the stick goes the other way, the boot acts like an accordion. There is a bulge in the design to help facilitate that action.
 
Luke D said:
Ours are designed be secured around the pushrod with enough tension that they do not slide. You shift the stick to the travel limit and then secure the boot in such a way that the boot does not move on the tube, but also can not limit travel. When the stick goes the other way, the boot acts like an accordion. There is a bulge in the design to help facilitate that action.
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Anything attached to the pushrod that can absorb and hold moisture will be at
some risk for corrosion. However, a properly primed and painted push rod and regular inspection should mitigate the concern. There are thousands installed out there and this one post in the 30 years I have been around RV’s is the only one I recall seeing. It’s good you are chasing this down but I wouldn’t sweat too much about it.
 
My pushrods are primed, but I'll probably throw a quick layer of rattle can paint over that inner portion as well. Between primer and paint (even cheap stuff) and a checklist item to undo and inspect each annual, I don't think I'll lose any sleep over it. If the boots do their job of keeping out cold air, this cold blooded dude will need them!
 
All pushrods should be primed at minimum...They are not alclad (no extrusion is unless its rollform extruded) , and they should be primed or primed and painted. since condensation and rain/wash water trickles down hill, it will end up at the root/boot due to dihedral. Aircraft 101, watershed protect everything inside and out, leave no cavity that holds moisture.
 
There was one with severe corrosion in the UK a couple of years ago. It was documented in the LAA mag at the time. About 1/3 of the circumference was gone!!!! The issue may have been that a hose clamp had been used to secure to the tube. You then have aluminium and galvanised steel with a probably damp material between, ideal conditions for dissimilar metal corrosion and the aluminium would be the sacrificial anode. My RV lived next to this one in the hangar but has elastic to hold the boot on the tube, no sign of corrosion on mine, thankfully.
 
Thanks for all of the comments. It's certainly been helpful information for me, and hopefully for others too.
 
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