Under Carriage Holes
Thread Starter
Instructor
Joined: Jan 2006
Posts: 129
Likes: 0
From: Oakville ON
Under Carriage Holes
I am new to the form, and looking for some advise. I purchased a 2002 last year with about 5K, I have since been able to verify the mileage through GM Canada workorders so I am not concerned that I bought some thing other than what I expected.
However when doing an inspection this year after winter storage I discovered two holes in the under carriage. Cearly someone did not know what they were doing and when they put the car on a hoist they punched two holes in the floor board, passenger and driver side, approx 1" x 1/2", looking for suggestions on how best to patch these holes.
Thanks to all from Oakville Ontario Canada,"keep the wave"
However when doing an inspection this year after winter storage I discovered two holes in the under carriage. Cearly someone did not know what they were doing and when they put the car on a hoist they punched two holes in the floor board, passenger and driver side, approx 1" x 1/2", looking for suggestions on how best to patch these holes.
Thanks to all from Oakville Ontario Canada,"keep the wave"
Racer
Joined: Dec 2003
Posts: 448
Likes: 1
From: Naples Fl
patches
Be careful How you patch the holes. If I remember correctly the floor pans are a lamination of fiberglass with a balsawood core. If you weld down there even if the outer skin is alum, it will likely burn the core and cause other damage. Perhaps the holes can be filled with an epoxy or something similar. Its where you cant see it anyway and unless it is all the way thru it should be a relatively easy fix. Do some research and wait for some more input from the forum. There are a lot of experienced guys out there. They may know some others with similar problems/fixes. Good luck.
Thread Starter
Instructor
Joined: Jan 2006
Posts: 129
Likes: 0
From: Oakville ON
Originally Posted by jl240z
Be careful How you patch the holes. If I remember correctly the floor pans are a lamination of fiberglass with a balsawood core. If you weld down there even if the outer skin is alum, it will likely burn the core and cause other damage. Perhaps the holes can be filled with an epoxy or something similar. Its where you cant see it anyway and unless it is all the way thru it should be a relatively easy fix. Do some research and wait for some more input from the forum. There are a lot of experienced guys out there. They may know some others with similar problems/fixes. Good luck.
Thank you for you help.
Melting Slicks
Joined: Dec 2003
Posts: 2,340
Likes: 722
From: Chicago N/W Suburbs
What comes to my mind, assuming the metal has broken through with concern of water soaking the Balsa wood.
Use clear or gray colored silicone caulk, the kind used on house windows. Buy the pure silicone with the 50 year durability. Be sure to clean the surface with windex and let dry before applying the caulk. You can buy that type of window caulk at Lowes, Home Depot, Menards, Builders Square, Ace Hardware etc.
You may need to do it in multiple steps if the hole is too big and without some scrap metal inside the hole to suppor the caulk. Use a putty knife to smooth it out for a nicer look.
If the floor is simply dented without broken metal, just leave it alone. Anything you do will make it look worse.
Use clear or gray colored silicone caulk, the kind used on house windows. Buy the pure silicone with the 50 year durability. Be sure to clean the surface with windex and let dry before applying the caulk. You can buy that type of window caulk at Lowes, Home Depot, Menards, Builders Square, Ace Hardware etc.
You may need to do it in multiple steps if the hole is too big and without some scrap metal inside the hole to suppor the caulk. Use a putty knife to smooth it out for a nicer look.
If the floor is simply dented without broken metal, just leave it alone. Anything you do will make it look worse.
Safety Car
Joined: Nov 2003
Posts: 4,979
Likes: 5
From: San Diego, CA "leaf" "tee" "e"
Originally Posted by C52002
Cearly someone did not know what they were doing and when they put the car on a hoist they punched two holes in the floor board, passenger and driver side, approx 1" x 1/2", looking for suggestions on how best to patch these holes.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The floor boards on ALL C5's are Sheet Molded Composite (SMC) with a balsa wood core. The floor panel is 1/2" thick in most places (except where the depressions and indents are made for mounting things. The floor pans on the C6 Z06 are carbon fiber with the same balsa wood core. Man that thing is stiff and very light!
What I would do is clean up the edges of ruptured SMC so that they are smooth and clean. Remove any damaged balsa wood core. GM Body shops and even your Local Body shops sells an epoxy mastic for gluing SMC to SMC and SMC to metal (same stuff that mounts the floor panels to the metal cross braces and the body. That is what I would use. It is very thick and will be able to be squeezed in to the void and you can apply some cellophane over the damaged area and then cover it with duct tape to keep it in place until it sets up. When you pull the tape off the cellophane will keep the mastic from sticking to the tape!
Once it sets up, you can sand it flush and smooth. That would be the best and most permanent repair.
Please let us know what you decide to do and how the repair turns out.
Bill C
What I would do is clean up the edges of ruptured SMC so that they are smooth and clean. Remove any damaged balsa wood core. GM Body shops and even your Local Body shops sells an epoxy mastic for gluing SMC to SMC and SMC to metal (same stuff that mounts the floor panels to the metal cross braces and the body. That is what I would use. It is very thick and will be able to be squeezed in to the void and you can apply some cellophane over the damaged area and then cover it with duct tape to keep it in place until it sets up. When you pull the tape off the cellophane will keep the mastic from sticking to the tape!
Once it sets up, you can sand it flush and smooth. That would be the best and most permanent repair.
Please let us know what you decide to do and how the repair turns out.
Bill C
Vette Dan
Joined: Sep 2004
Posts: 1,043
Likes: 1
From: OKC Oklahoma
If you are talking about holes in the frame on the outside they are the spots for the jacking pucks. From your last post that is what I think you are looking at.
Do you have a pic or draw us a position of these holes.
Do you have a pic or draw us a position of these holes.
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Melting Slicks
Joined: Mar 2003
Posts: 2,512
Likes: 49
From: Franklin IN
Originally Posted by Bill Curlee
The floor boards on ALL C5's are Sheet Molded Composite (SMC) with a balsa wood core. The floor panel is 1/2" thick in most places (except where the depressions and indents are made for mounting things. The floor pans on the C6 Z06 are carbon fiber with the same balsa wood core. Man that thing is stiff and very light!
What I would do is clean up the edges of ruptured SMC so that they are smooth and clean. Remove any damaged balsa wood core. GM Body shops and even your Local Body shops sells an epoxy mastic for gluing SMC to SMC and SMC to metal (same stuff that mounts the floor panels to the metal cross braces and the body. That is what I would use. It is very thick and will be able to be squeezed in to the void and you can apply some cellophane over the damaged area and then cover it with duct tape to keep it in place until it sets up. When you pull the tape off the cellophane will keep the mastic from sticking to the tape!
Once it sets up, you can sand it flush and smooth. That would be the best and most permanent repair.
Please let us know what you decide to do and how the repair turns out.
Bill C
What I would do is clean up the edges of ruptured SMC so that they are smooth and clean. Remove any damaged balsa wood core. GM Body shops and even your Local Body shops sells an epoxy mastic for gluing SMC to SMC and SMC to metal (same stuff that mounts the floor panels to the metal cross braces and the body. That is what I would use. It is very thick and will be able to be squeezed in to the void and you can apply some cellophane over the damaged area and then cover it with duct tape to keep it in place until it sets up. When you pull the tape off the cellophane will keep the mastic from sticking to the tape!
Once it sets up, you can sand it flush and smooth. That would be the best and most permanent repair.
Please let us know what you decide to do and how the repair turns out.
Bill C
I used this stuff on my C-4 87 Vert. to replace the rear deck it bonds very well to SMC but even better to metal. In the C-4 there are some steel support brackets I had to grind the old stuff it would not split or chisel off. The stuff I used was made by Ashland Chemical they make several cure rates so be sure you know your open time or it will set up on you before your ready. Mine was set to kick off in 45 minutes that gave us time to position the panel before it set. Any questions about it email me.
