It has always bugged me how the C6 seats don't have sufficient support and the leg bolster went soft especially the left side of the driver's seat. The 2005 seats seem to be the worst. I recently sat in a 2008 and it seems to be slightly improved over the 2005.

Last year, I disassembled the driver's seat to firm up the center area under my butt to eliminate the hip pain it was causing me after only 15 minutes and to figure out why the left bottom seat bolster had started to go flat. I posted photos of that job.

This time, my mission was to add support under the left bottom bolsters to keep them from sagging. As many of you may have discovered, the driver's left seat bolster takes your full weight while getting in and out of the car. After a few hundred times, the left bolster goes flat and a deep crease appears in the cover. The seats don't have much support in high cornering G's. To fix that, it would take a complete redesign with new seat covers or new seats.

The first step is to remove the seat. Unbolt the front and back mounts, disconnect the wires and lift it out. Make sure you cover the sill with a couple of towels to prevent it from being damaged by the metal seat mounts. Its heavier than it looks with all the motors and metal brackets.

Next, set it on a mobile work bench so you can have access to all sides. I recommend putting up a couple of saw horses with a sheet of plywood and carpet on top so you can move it around and not damage the vinyl or leather.

To disassemble the bottom cushion cover, various flaps are held together with Velcro and hog rings. I clipped the hog rings with wire cutters and used tie wraps on reassembly.

The plastic side control panel is held on with one screw. The lever to adjust the angle of the seat back is held on with a "C" clip that you can release with a small screw driver thru the slot on the bottom. The front button just pops off. Once you get the these off, the plastic cover slides forward and up to remove. There is a metal plate under that is attached with three screws.

The leather seat cover is held in place with a string around the bottom. Untie the string and the whole leather seat cover will come off. You don't have to mess at all with the seat back.

Once the cover is removed, the seat foam cushion will lift off the wires. You will notice the support wires in the middle going front to back. However, there is nothing under the side bolsters!!! No wonder they sag over time!

The foam on the driver's left side was removed by the factory behind the seat controls panel. Actually the seat foam for both seats is from the same mold. They just remove the foam where the seat controls are mounted.

I glued the white/blue foam under both bolsters to fill the large gap between the bolster and the seat frame. This will prevent the bolster foam from dropping down into the gap between the wires and seat frame.

I glued ballistic nylon fabric to the bottom seat cushion to keep the support wires from cutting into the foam over time. I added more ballistic nylon over the wires themselves to firm it up.

The glue and foam were purchased at a local commercial upholstery supply store.

Here are pictures of the process:

Additional foam (blue/white) under the bolsters and ballistic nylon glued in place on the original seat foam. Wire support covered in ballistic nylon to firm it up.


Here is a picture of the ballistic nylon covering the wires and to the right is the left side seat frame and the gap under the bolster that will be filled with new foam.


Red line indicates where the factory removes molded foam between the seat frame and the seat control panel. The foam sits right on top of the seat frame and over time, tears causing it to sage due no support under the bolster. Blue foam was added to fill the large gap under the bolster which will keep it in it's original position.



Same thing with view from below. Notch cut in foam to clear bracket on seat frame.




Duct tape was added to cover the sharp edge of seat frame and prevent it from tearing bolster foam.



Below is the driver's seat right side bolster. Note the area highlighted with red dots is the section that the factory removes when installed on the passengers seat.



Finished driver's seat. Note driver's left side bolster is now at the original height and shape. With the added foam between the bolster and seat frame, I don't anticipate it will sag anytime soon.



Almost done.


Finished.

 

Thanks - Nice write-up and pics!!

Bob

 

Nice write up.. Sad thing is,these are many of the same problems the C5 seats had and nothing was corrected. Seat support wires cutting through the foam, and the bolster foam getting cut by hard metal edges of the frame.

 

I used foam in a can in the same areas as the blue foam from underneath the seat

 

Is the blue insulation just the rigid foam type - looks like it in the pics, but this would break up into tiny bits in no time...

Mez - could you clarify??

 

I did the install of the Denier material on the springs as per the OP.

Be sure to use a high density foam meant for upholstery.

 

Great job and great write up! Too bad GM continues to put in these crappy seats and ignore the complaints. We shouldn't have to do this ourselves. I have an 08 with <10K miles on it and my driver seat looks like its 10 years old!

 

I used the denier ballistic nylon as well (3 layers)
I then spray glued a strip of ballistic nylon on the outer upper seat bolster foam to keep them from ever seperating as they always do!!! I just installed black\silver Katzkin leather seat skins with the C6 logo stitched in. 1000 times better than the old!!

 

Great job and pictures.

 

My driver seat looks like it's got 10K miles on it and I only have 1K miles on it...matter of fact, the driver seat looked like crap when I bought the car w/ 30 miles on it...

I'm having the foam and cover replaced under warranty. Also having the pass seat bottom cover replaced due to a horrible line in the leather.

If I keep this car any lenght of time I will have the seats custom done or outright replaced.

It is my only complaint with the car.

Funny, but I did not feel this way about my '05 or '06...but those were part time cars...the new one I now have is a DD, and my only ride.

However...I love drivin' this car everyday.

 

No, this is what the upholstery shop calls high density foam. It is not rigid and definitely is firmer than the factory foam and will last a long time.

Find an upholstery supply store that does wholesale and talk with them. In the back, they had rolls and huge blocks of foam for chairs and sofas. Where I bought it, they only carry 1 inch high density foam. I bought 2 yards...one for a chair in the house that was sagging and the other for the Corvette. It was cheap. You also need to buy the spray glue for the foam. Once you glue it into place, it will stay for good.

The nylon over the springs really does the job in firming up the bottom. 3 layers is a good idea, too. If you have an old duffel bag, cut that up and tie wrap it into place.

I did this a month ago and in my opinion is 1000% improved....firmer with no sagging and the bolster holds my butt better in the seat but it still not as good as others. The seat looks the same. You will definitely feel the bolster is firmer when you get in and out of the car. Especially if your foam was ripped.

 

Thanks Tom

 

Nice write up/pics.

I'm preparing to have similar work done to mine. This will be a valuable guide.

Thanks.

 

Someone claimed that the newer cars come with mat already installed on top of the seat bottom wires, like the DIY nylon discussed here.

Wondering if my 2009 3LT would have something already?

 

Bringing this thread back from the dead.

I recently did the same thing to a 2002 C5. It had exactly the same problem as my 2005 C6.

Depending on how firm you want the bottom cushion, you can add more material. I added .25" of jute padding between the wires and the foam to see what it would feel like. Really made the seat firmer and just a touch higher at first, but I've gotten used to it. I don't recommend this for everyone.

After 6 months, I am totally happy with the mod.

Anyone interested in doing this, contact me.

 

Thanks for bringing this up, I hadn't seen it!

Your posts and work making life better for us Forum members is much appreciated!

The passenger seat weighs 53 lbs equipped with airbag. I dropped it on my toe while weighing it over the weekend. It felt like 150 lbs on my toe!

 

Thanks. As you may know, my shifter bushing repair kit is being distributed through some of the Corvette Forum vendors.

In the case of the seat, the root problem is the poor support system under the foam. Its not the foam. Its the support under it.
I have created a seat repair kit and am pitching it to the Corvette Forum vendors.

The solution to the seat took some thought but I think I have something that works very well. If anyone wants more info, please contact me.

I love to create cost effect & practical solutions to fix very fundamental problems. However, not all my ideas work. I tried to create the best oil catch can for under $5 using readily available material. The one I worked on the most was based on the Venom energy drink aluminum bottle. Its the thickest one I found. But it required too much work to braze the tubes. I even looked at buying a quantity of commercial aluminum bottles but could not find the perfect size. I tried PVC, but the under hood heat softened it up too much. So I gave up and bought a CCA catch can. Oh, well...

 

Low bid seats made by LEAR. Did I mention that LEAR went BK, but did come back so that they could continue to build quality parts like these seats.......

 

You're the kind of innovator that makes this country what it is. Thanks!

 

Great job.