Removing C4 seat base studs
Thread Starter
Team Owner
Joined: Dec 1999
Posts: 34,873
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Removing C4 seat base studs
What's the easiest way to remove the seat mounting studs in the C4 floor? The threads on a couple of these studs are pretty well mangled and I also want to install the VetteWorks harness mounting brackets.
Can I simply cut the studs at floor level and pound them out? Then ream out the holes and use something like Grade 5 bolts and flat washers?
I want thicker studs (maybe 3/8"?) and also slightly taller so I can mount the new brackets for my harness belts and the mounting brackets for my Corbeau seats.
Can I simply cut the studs at floor level and pound them out? Then ream out the holes and use something like Grade 5 bolts and flat washers?
I want thicker studs (maybe 3/8"?) and also slightly taller so I can mount the new brackets for my harness belts and the mounting brackets for my Corbeau seats.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
The studs?
Those are made into the floor pan as far as I know. They are solid when not nutted, and I do not recall seeing a bolt head on the underside...If they were just thru bolts they would never handle the stress of a seat and 200 lb drivers shifting the load around all day on 4 studs...Knowing that floor is composite or glass and NOT metal, thats a challenge. They might be threaded into a receiver, so if a close inspection agrees with that, then you might try to double nut one and use an impact to see if it will reverse out.
My guess would be that there would have to be some repair/reinforcement done to the floor if the studs were beatin out or the floor broken to remove them.
Those are made into the floor pan as far as I know. They are solid when not nutted, and I do not recall seeing a bolt head on the underside...If they were just thru bolts they would never handle the stress of a seat and 200 lb drivers shifting the load around all day on 4 studs...Knowing that floor is composite or glass and NOT metal, thats a challenge. They might be threaded into a receiver, so if a close inspection agrees with that, then you might try to double nut one and use an impact to see if it will reverse out.
My guess would be that there would have to be some repair/reinforcement done to the floor if the studs were beatin out or the floor broken to remove them.
Cruising
Joined: Nov 2011
Posts: 11
Likes: 1
The studs for the seat are attached to a strip of metal which is riveted to the underside of the floor. The studs just pass through holes in the fiberglass. The two front studs broke off on my driver seat. I drilled the rivets out and removed the factory strip and made my own by drilling holes through a strip of metal and welding bolts to it then riveting that to the floor. As I recall it was a pain to get the factory strip to detach from the floor. If you look underneath you will see it. I think there may have been some adhesive along with the rivets.
Thread Starter
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Had a chance to get under the car to take some pics. The rear studs have individual metal plates under the car. The head of the stud is smooth and looks like a rivet head.
The front studs have a single plate that runs about the width of the footwell and there are small rivets that pass thru the plate and floorpan. The holes in the floorpan for the front studs appear to be elongated and there is some factory sealant visible in the hole and around the stud. So I assume that entire front under-car plate would have sealant applied and riveted in place.
The floorpan is part metal as a magnet will stick to the floorpan.
Here's a couple of pics showing the plates under the car:
The front studs have a single plate that runs about the width of the footwell and there are small rivets that pass thru the plate and floorpan. The holes in the floorpan for the front studs appear to be elongated and there is some factory sealant visible in the hole and around the stud. So I assume that entire front under-car plate would have sealant applied and riveted in place.
The floorpan is part metal as a magnet will stick to the floorpan.
Here's a couple of pics showing the plates under the car:
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
Yeah, I knew it had to be some reinforced plate deal...there is no way the glass floor pans could support that kind of stress alone...
Once drilled and dropped, be sure to reseal the plates and bolts where they pass thru...silicone or some undercoat of some kind. I'm taking my seat out when it warms up later...for some housekeeping in there and I need lunch money for the week..
Driver side seat = savings acct.
If I see anything useful to this project I'll post that later on.
Once drilled and dropped, be sure to reseal the plates and bolts where they pass thru...silicone or some undercoat of some kind. I'm taking my seat out when it warms up later...for some housekeeping in there and I need lunch money for the week..
Driver side seat = savings acct.
If I see anything useful to this project I'll post that later on.
Thread Starter
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
I think I will remove the rear studs and plates as the plates are only 2" long and the existing studs are about 1/4" in diameter. I can then use a single piece of flat stock to hold two new bolts. I measured the width of that recess under the car and it should allow for using at least 1 inch or maybe 1 1/4" wide flat stock. Then I can add one or two smaller bolts and nuts (or even rivets) to provide additional strength/support.
The important thing with sealing everything is to clean off all of the existing sealer so that something like silicone will stick. I might even use something like a spray-on undercoat as a final step.
The important thing with sealing everything is to clean off all of the existing sealer so that something like silicone will stick. I might even use something like a spray-on undercoat as a final step.
Racer
Joined: Sep 2010
Posts: 325
Likes: 8
From: Princeton Jct. New Jersey
If the seat mounting studs are o.k. why not just leave them and drill some new clearance holes through the reinforcing strip/floor pan along side the studs and mount your harness with 3/8 stainless hex bolts, nuts, and washers?
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Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
You could even use a coupler to screw all the way down onto the studs, then screw a short stud into the coupler to accept the seat bracket...or just use a bolt to drop down thru the bracket to the coupler. That might raise the seat 1/4-1/2"...if you;re under 6' shouldn;t be an issue.
Drifting
Joined: Aug 2000
Posts: 1,758
Likes: 4
From: Medford, Or
George,
I just cut the studs down to the base and drilled down through the middle and tapped a 7/16" fine thread into the hole and screwed in the bolt up through the bottom. I allow n 1" passed the hole for room to play with.
Dan
Vetteworks
I just cut the studs down to the base and drilled down through the middle and tapped a 7/16" fine thread into the hole and screwed in the bolt up through the bottom. I allow n 1" passed the hole for room to play with.
Dan
Vetteworks