How do you replace a seat return spring?

[Frank Cox]

The spring that makes the seat fold up occasionally breaks. Fortunately I have some spare seat pans (or whatever they're called) so I just swap that out and when I have three or four broken ones I take them to the local machine shop and the guy there changes the springs.

But I've just discovered that he's now retired so that's no longer an option and I'm trying to do it myself.

Unfortunately, I have no idea what I'm doing. He got me a box of springs a few decades ago, so while I have the springs and the seats I lack the know-how to put them together.

The first photo is a seat with a spring that's not broken. (When they break one of the little wings falls off.)

It looks like the way to take it apart is to straighten the ends on that big cotter pin and then the old spring will slide right off.

But the next step is what has me stumped.

The second photo shows a new spring "at rest". It appears that you have to somehow bring the lower wing up so it's higher than the other wing and then it will slide right onto that axle on the seat edge.

But how do you do that? It's not a super-strong spring but it's more than I can just twist in my fingers so I assume there's some way to squash it using... something... so those wings move into position and you can hold it to slide onto that axle.

The other two things in the second photo are pieces that were in the box with the new springs. I assume it's some kind of leverage device that the machine shop guy made to deal with this but again, I have no idea how to use it.

[Ryan Gallagher]

Just based on your photos. Yeah the U shaped pin is the keeper. Bend the tips straight to remove Once that is off you just want the new spring to be tensioned identical to your good example. I would guess the bar stock with the holes was a good tool to grab one prong of the spring and manipulate it against part of the frame acting as the stop on the other half, perhaps needed to remove or install the U pin with the correct relationship to the loaded spring?

[Ryan Gallagher]

Or if the spring does not fit on the axel, both holes in the bar stock might permit the twist to open the spring to the needed diameter. Either as you slide it on, or on a rod/dowel that does fit inside it first?

Edit: hah, I just noticed the rod on the photo, so yeah, insert that in the spring to make the other tool useful. Your guy gave you a full kit it seems!

[Frank Cox]

The distance from the spring axle to that green bar is fixed, so I think the wings on that spring have to somehow go over and under that bar before the spring can slide onto the axle, and the wings have to be turned and held in position to do that.

Once that's in place I could probably just lever those wings with a screwdriver to slip the big cotter pin back into place and shove it into the holes in the axle.

But I'm stumped on how to turn those wings and hold them in place so I can get them over and under that green bar and then slide the spring onto the axle. I need to somehow twist the wings around so the one that's naturally on top is on the bottom and then hold them in that position while I put them over and under that bar and then get the spring onto the axle. It's a question of how to keep the tension on that spring so those wings stay where they need to be while I push them into place and slide the spring onto the axle.

[Ryan Gallagher]

Maybe the holes are a red herring for that step. You could insert the rod and then use the flat of the bar stock to compress the tangs to the parallel arrangement as you try to get it on the post. At least then the bar stock could be removed and one spring tang could be grabbed if needed using the holes to insert the U pin. But compressing them will make the diameter smaller not bigger as it sounded you needed.

i also gather the tube pictured on one of the spring tangs was a mod to increase the spring tension for aging springs, or maybe they were all like that cause the spring needed a little bit more umph.

a pair of vice-grip locking pliers might also be handy?

the over under while inserting is a bit of a puzzle as you point out.

[Mike Blakesley]

Do you know what brand seats those are?

[Frank Cox]

They are Irwin brand seats.

I bought them "used" 30 years ago and over the course of time I've had several of them reupholstered and some of the springs replaced, but the seats themselves are still in pretty good shape.

[Jim Cassedy]

We've got about 750seats that were pulled out overnight sitting in a dumpster
behind the theater. I don't know what make & model they are, and I won't have
time until later today to see if they have springs similar to the ones you're looking for,
but I can probably save awholebunch of them from winding up in the dump if they
are ones you can use. - Jim C -

(I had to climb up on the roof to get this picture)
DumpsterSeats_1.jpg

The complete seats are there but I might have to dig through this to find a bottom with springs.
DumpsterSeats_2.jpg

[Frank Cox]

Thanks ever so much for the offer, Jim, but I actually have a whole box (well, probably a half-box) of the springs. So parts aren't an issue, it's just a question of how to install the spring onto the seat.

I currently have three of those seat pans with broken springs in the basement. One of these days when I feel ambitious I'm going to take one of them and see if I can manage to do this job.

The machine shop guy did it somehow so it obviously can be done. It never took him long; I'd drop the seats off in the morning and pick them up after lunch.

I'll post an update when I've actually tried to do this. I haven't made any attempt yet past looking at it and posting those pictures here.

[Ryan Gallagher]

If you can get a look at one that he has definitely repaired... maybe there are more clues there. I would hope not necessary, but I suppose there is a chance he grinds off the horizontal bar in the seat pan and re-welds it to achieve the over-under.

[Frank Cox]

The photo I posted in my first message is one that he repaired some years ago.

[Mark Gulbrandsen]

What? You don't have recliners yet? I'n not coming to your theater... . Seriously, I hate recliners as none of them fit me correctly, and that generally means being uncomfortable for 2 hours. At 5 foot 8, recliners and I are a total mismatch. So keep the seats as long as you can...

[Ryan Gallagher]

What? You don't have recliners yet? I'n not coming to your theater... . Seriously, I hate recliners as none of them fit me correctly, and that generally means being uncomfortable for 2 hours. At 5 foot 8, recliners and I are a total mismatch. So keep the seats as long as you can...

You'll be happy to hear our upgraded seat plans are not recliners. But they are adding some kind of cup holder, which I'm conflicted about in a historic venue. lol. Preserving seat count as much as they could was the primary goal, we are still losing some for new ADA access.

[Frank Cox]

My seats (and most of the film and sound equipment that I got when I made this theatre) came from a theatre that went bust in BC right around when I was setting up this one. So the timing worked out well for me, maybe not so much for the chap that went bankrupt though.

I think the guy must have had the world's worst location. He started out for it to be a regular movie theatre and nobody came. So he changed to a theatre showing older discount movies and nobody came. So he changed to a porno house. And nobody came.

And that was that. I swooped in and got his projector, sound system, and a bunch of miscellaneous stuff. I'm still using the seats. I'm trying to recall if I'm still using any of his other equipment today but I don't think so.

[Randy Stankey]

So he changed to a porno house. And nobody came.

I think I'll just let that one go. Too easy!