Fixing rear seat springs in 1985 300td

[Chad300tdt]

I created this post elsewhere in June of 2007 and I decided to post it here to make linking it easier.


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I read every thread I could find about fixing the sag in my rear seat springs. The threads only mention the front seats, so I thought they should be at least similar.

The difference is that the back seat bottoms are coil springs so the pool noodle fix was out, as was the metal tubing and bailing wire fix. After some research I found that upholstery shops stuff cloth into the coils to stiffen them up. I found this to be inadequate, so I tried cutting some poly foam into thick strips and weaving them in between the coils. I then put a piece of foam under the horse hair mat (A thorough spray down with Febreeze got rid of the funky smell in the mat).

The seat cover has ribs that are shaped by felt and foam strips inside. the ribs on my seat looked flat and stretched out because the muslin underneath was shredded. I had to stitch a new piece of muslin inside to reinforce the ribs. The seat now looks and feels amazing.

I am just waiting for a set of hog ring pliers and rings to arrive so I can put it back together properly.

I only did this to the rear right seat so far. I am doing the rear left next and expect to finish it in 1-2 hours now that I know how to approach it and what supplies to have at hand.

There may be better fixes for this problem, but in my case, I had all the supplies laying around (except hog ring clips and pliers for $18.99 from JC Whitney) so it was basically a free fix.

Very satisfying! I will post a few pics when complete.


covering the shredded muslin liner.


new muslin sewn in.


fixed seat cover.


seat springs stuffed with high density foam.


ready to relace the skins.


hog ring pliers to hold seat skins to seat frame.


clips in place.


finished seat.

This project was simple and made a big difference. I can now use a baby seat since the car seat is firm enough to support it.

If you do this method of repair, I would suggest that you test fit the seat in the car before putting the clips and skin on. If you overstuff the springs, you will lose headroom for your passengers. Luckily, I thought to test fit and had to remove some stuffing. Everything is great now. I hope this helps someone out there.

I also welcome any comments of other ways to do this. I know there is a way to use supplemental coil springs, but I chose this way since it cost me very little.

Thanks,
Chad

[Mike D]

Nice job! Most Ace Hardware stores also carry the hog ring pliers.

Of course, to really do the job right you should have arranged the different colored foam into a Mercedes star!

[rg2098]

Beautiful write-up!

[Dee8go]

So, Chad, was the foam not there originally? I wonder how long that will last? Where do you get memory foam? This is the stuff like the Tempurpedic mattresses have in them?

[Dee8go]

Originally Posted by Mike D

Nice job! Most Ace Hardware stores also carry the hog ring pliers.

Of course, to really do the job right you should have arranged the different colored foam into a Mercedes star!

Everybody is a critic . . . .

[Chad300tdt]

Originally Posted by Dee8go

So, Chad, was the foam not there originally? I wonder how long that will last? Where do you get memory foam? This is the stuff like the Tempurpedic mattresses have in them?

No, there wasn't any foam in the seats, just the coil springs which were so tired you would sink almost to the floor when you sat in them.

I got the foam at the local fabric store (Joann fabrics). They have an upholstery section where you can buy high density foam (like I used) and memory foam. The memory foam is much more expensive.

As far as how long it will last, I did this almost two years ago and there is no sign of wear to date. The seats still feel like they did the day I stuffed them.

[KAdams4458]

My goodness, that is a lot of foam. That had to take a while!

I find the W123 seat springs to be an interesting topic, so I'm happy to see some wagon info discussed, even though I'm not a wagon owner.

So, the wagons used a metric butt-load of coils for the rear bottoms? The Sedans, from what I have seen, all use the kinky flat springs in the rear which would, as you suggested, benefit from the pool noodle and brake line approaches.

[Dee8go]

Maybe I'll try that on my driver's seat. It's sitting pretty low now. Thanks, Chad.

[Bill Wood]

This DIY is now in the Wiki HERE.

Thanks!

[Chad300tdt]

Cool, thanks Bill.

[Dee8go]

My god, Chad, now you've been imortalized in the pages of Wikipedia!

Is there anything else you wish to accomplish in this life?

[jjtaras]

Chad:

What size hog rings did you use on your seats? I took mine out and pitched then without bothering to note their opening size (smart move!).

Thanks,

Jeffrey

[Chad300tdt]

Originally Posted by jjtaras

Chad:

What size hog rings did you use on your seats? I took mine out and pitched then without bothering to note their opening size (smart move!).

Thanks,

Jeffrey

I just got the only hog rings and pliers from JC Whitney. It's more expensive from them now, but it says the hog rings are 3/4" upholstery rings.

Newark Auto Products 401-pc. Pliers and Hog Rings Kit - JCWhitney

I also saw them for sale at Home Depot recently. They have 1/2" rings which will still work but cost less.

YARDGARD 12-1/2-Gauge Hog Rings (200-Pack)-328604B at The Home Depot

Prime-Line Hog-Ring Crimper-HR 14000 at The Home Depot