Where is my Encore damper linkage binding up?

[SonOfEru]

I have a Defiant Encore 0028. So it's pretty old but it was only used for 5 years by the previous owner and then I got it last year.

This year the linkage for the damper plate began to get harder and harder to swing into cat mode. It would seem to catch, to bind up, about 1/3 of the way through to the shut position, so I would have to bump it a bit to get it past that point. I asked here about it and was recommended to put some high-temp anti-seize grease on it. So I put some on the tip of the .... torsion bar, it's called? .... the rod at the back of the damper plate that slides in a slot with a tab screwed down on it to hold it.

As soon as I did, it started swinging free and smooth. Great!

So I closed it up and went back to burning, but after a week or two it started binding up again, just faintly and then back to where it was before. Rats. I guessed the grease didnt stand up to temp after all, even though I dont very often go over 1000* on my Auber probe.

So that time I took off the cover on the side where the linkage runs from the handle to the torsion bar, thinking I would grease everything. As soon as I greased that linkage, it swung free and smooth, BEFORE I even put any on the back of the damper. Perfectly free swing. Seemed curious.

Well, again after a couple of weeks it began to bind up, just like before. So once again I greased the back of the damper at the torsion bar slot and once again it swung free and smooth, WITHOUT any grease on the linkage bar

And now it has started to bind up again.

This is really curious. You can see the puzzler - two locations, either one of which can get greased and make it swing nicely. Either one of which seems to solve the problem completely, as if the other one was never a problem.

I have thought that the linkage bar probably has some wear, where the round steel rods go through the 2 holes in it, one at either end. I can imagine that if there is too much play in one or both holes, it could become hard to get past a certain point as the angles and forces change throughout the throw of the whole closure. So I am about ready to get a new one, but I'm still puzzled and not at all confident that it's going to solve things

Anyone ever experience this? Any clues, any advice?

BTW it always swings open perfectly freely, it's just the closing that gets stuck.

Thanks

SonOfEru

 

[DAKSY]

Check the hole where the damper rod passes thru the left side casting. The cast iron is
softer material than the steel rod & sometimes that hole wears egg-shaped & causes the rod to bind...
If THAT'S the issue, the only fix that I know of is to replace the left side.
Seems to me that the hole should have been bushed with harder material at the factory & if it
wore out, a new bushing could be re-inserted, but what do I know...

 

[SonOfEru]

Yeah, what do WE know ...

I thought of that too but, being the sort that looks at things like science experiments in school, you try to isolate the possible causes and then test them one by one BY THEMSELVES. So what I did felt like that kind of thing - grease the back of the damper, it frees up, so that was the cause. When it came back, and I greased the linkage bar and NOT the back of the damper, how did it swing free if the damper was the cause.

As for that, if there were a problem at that hole, then how would greasing the other locations make everything so smooth and friction-free?

Is puzzlement.
["The King and I"]