C4 seat into a C3

DeeVeeEight

Fast Pedalphile
Joined
Nov 3, 2008
Messages
2,284
Location
Southern New Jersey, USA
The weather was great and I figured it was a good day for a "driveway" project (no garage for me yet) so I gave installing a C4 seat in to my C3 a try. Here's how it went.

Here's a comparison of the two seats.
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Here's my old headrest. Hey it was better than banging my head on hard plastic.
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All you need to do to get the bottom cushion loose on the C4 seat is to pop this spring clip off.
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After removing the old drivers seat and removing the seat tracks from the bottom of the seat I temporarily reinstalled the seat tracks for a test fit.
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The front left corner on the C4 seat bottom lines up with the C3 seat track nicely.
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The back left corner needs to be drilled. I chose to go as far back as I could so the the heads of the bolts (which come up from the bottom) would not interfere with the slider mechanism. I used a fender washer in this location to spread out the load.
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Here you can see the new bolts in the corners, with the exception of the left rear, it wasn't installed yet in this picture. I tried to use stock locations for strength and safety. Due to space limitations I used nutzerts instead of lock washers. The front right corner is the weakest mounting point because it is no longer reinforced. Well, you can't have everything....
I also cut out the bottom of the C4 seat to accommodate the slider lock/release arm, it works smoothly.
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Here is the seat installed. I used Linesman type pliers to hook the heavy wires on the back of the seat cushions in to the clips on the seat frames, it worked really well.
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The C4 seats are way more comfortable than the C3 seats are. You do sit about 1/2" or so higher but the C4 seat reclines a bit (it's adjustable) so your head won't touch the ceiling. At some point in the future I will look in to cutting and lowering the front seat track pedestals for an even better fit. At this point the sliders work so I am not limited to a fixed seat position.
 
The C4 seats are indeed more comfy, I feel they are even better than the C5 seats. They give a lot more sideways support. Do you have that gigantor stereo box securely fastened?
 
No, the box is not fastened. It is one more thing on my to do list. The box just clears the storage compartment doors when pushed back snugly. Any suggestions for pinning it down? I am afraid of screwing it in to the gas tank. The 600w amp is fastened to the back of the box (the whole shooting match is easily removed if needed) so screwing it in through the back is difficult.
 
The C4 seats are indeed more comfy, I feel they are even better than the C5 seats.

Yea, everybody's putting the C5 seats in now but they're flat and too tall and don't look right. There's not that much side support for the killer car its in. It ain't a sports car seat.
 
What chu doin' now DV8?
Jus' cain't leave well enough alone, I see.

Ah yes, the on going quest for the perfect ride, while tearin' up the "Twisties".
I think the seats look good.
If you're happy with 'em, that's what matters. :beer:
 
Yea, everybody's putting the C5 seats in now but they're flat and too tall and don't look right. There's not that much side support for the killer car its in. It ain't a sports car seat.

Nothing wrong with C6 seats IMO... I love mine... now, If was into racing the '79 some Sparco seats would be my first choice.... the c4 seats seem to be a good compromise between comfortable and side support.... :thumbs:
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The C4s have awesome side support, they are better than a lot of these purpose built sport seats out there, no joking! The tracks and especially the gear boxes are junk, they break easily but when it comes to side support they are awesome. And admit it, some sparcos or whatevers....looks a little ricer to me!
 
Now that I have the power lumbar and side bolster working in my C5 sport seats, I can just pump up the bolsters after I sit down so they are nice and snug. No side to side movement at all when cornering.
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Really like the look of those C4 seats.
How strong is it bolting it straight to the floor?
 
They are strong as the original in my opinion, just not adjustable any more. I went to my local hardware store and purchased some pre-drilled steel strips, cut them to length and mounted them to the floor at the original bolt holes, then mounted the seats to the metal strips. I did not drill into the floor of the car. I did drill the bottom of the C4 seats as close to the original mounting areas as possible to take advantage of the metal reinforced areas there, then I attached them to the steel strips. Once I tightened all the nuts and bolts the seats were jammed back as far as they would go and as jammed down into the floor as well. If you need I can go back and take some pictures and post them here.

I do like the C4 seats for comfort and support, the only drawback is that my left knee and the turn signal lever are too close.

Does anyone else get cramps in the ribs after driving their C3 for a while? I did with the old seats, I was constantly leaning forward from the belly up, pointing my chin at the windshield, steering with my left hand and shifting with my right. I'd get cramped up on my left side after an hour or so, the C4 seats have reduced/eliminated that problem.:thumbs:
 
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Ergonomics is so highly personal, MY take is the C4 seats from my '87 are one reason I sold the car...long list but that was near the top....I realize later C4 seats were better, but I never lived with them, just drove a few....

:clobbered:
 
Perhaps if I rode in a C4 seat in something other than a C4 I might learn to like them more. I prefer the C5 seats and I have my adjustments forward/aft and lumbars as well as upper side bolster squeeze.

Changed to the smaller diameter wheel when I installed the Jeep PS box.

Rich:beer:
 

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Ergonomics is so highly personal, MY take is the C4 seats from my '87 are one reason I sold the car...long list but that was near the top....I realize later C4 seats were better, but I never lived with them, just drove a few....

:clobbered:

That makes sense Gene. The C4 seats are not fat ass friendly.
 
Ergonomics is so highly personal, MY take is the C4 seats from my '87 are one reason I sold the car...long list but that was near the top....I realize later C4 seats were better, but I never lived with them, just drove a few....

:clobbered:

That makes sense Gene. The C4 seats are not fat ass friendly.

Yeh, I catch your shot there, I love U 2 asshole.....but my '87 seats had that side bolster crap in there way too snug, and funny part is the old vette club prez at the time was pretty wide fellow, and he sat in those style seats, the early C4, and we all used to smile about it....all in the bones man, just the bones, I guess.....I know GM did go to another style in later years, that was much more comfy, but I went to this '72 so left it all ....

:bounce:
 
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