Citabria 1998 7ECA sticky seat adjustment

[kubark42]

The forward seat on my 7ECA is very difficult to adjust forwards and backwards (I know, I know, everyone else has to swap cushions for adjustment so I shouldn't complain too much). I have to grab the seat base and push very hard forward in order to get the seat to slide. It's a little easier to go backwards because I can use my legs to force it back.

What is going on is that the bolts are so tight in the mechanism that it adds an unacceptable amount of drag. Unfortunately, if I loosen the bolt so that the mechanism is freer to pivot, it also introduces slop. In fact, the slop arrives before the mechanism drag goes away. So there's no sweet spot as things stand.



It seems that the slop is largely due to the fact that 1) the holes are not very precise and 2) the hinge pin is just a threaded bolt. I think the bolt is too short to be partially threaded, which means that the threads themselves are the bearing surface.

Anyone have experience with this? Suggestions for resolving it?

Or just live with it and thank my lucky stars that I've at least go it?

 

[Bartman]

technically, the bolts' grip is supposed to extend just past the depth of the hole with one standard washer used to keep the nut from bottoming out. replacing the bolts with new ones that meet that goal might be a good first step.

as for the holes, welding them shut and then dressing the surface back to flat and redrilling is a generally accepted fix but your IA would have to agree with that approach.

the bolts definitely shouldn't be so tight that the seat can't be moved.

 

[kubark42]

I removed the bolt to do some more investigating. I was wrong that the bolt was not partially threaded, but for sure the grip part is not long enough for the application.

I'm somewhat curious about the seat belts, as the webbing anchor was not installed with washers separating it from the seat frame. The upshot is that the flat anchor was mashed up against the round frame tubes, causing it to torque out of alignment. This of course is a source of friction.

I'll add washers to space the seat belt anchor away from the frame and then find a longer bolt to see how it all comes together. I'm also going to try inserting some thin delrin sheet and see where that gets me.

 

[Hiperbiper]

You might want to look at a parts manual and maintenance manuals for your aircraft. It will give you a parts (hardware) call out and show how the bolts, washers and nuts are supposed to be stacked. Anything else is un-airworthy. This is kind of an important part of the plane...

Chris