The Stovebolt Site Forums The Shop Area General Truck Talk Hole in floor under seat

Ok All, I have been searching for this for a good while. I can't find the purpose of the cross/key shaped hole in the floor under the seat. I have a 54 GMC 100 for reference. Any ideas on what that is for?

Supposedly, that was an exit hole for water/condensation?
(I have no documentation)

Supposedly there was a rubber plug that did not completely cover that hole.
(I have no documentation)

I know this has been discussed before. One of the pages in the FAM (Section 1, Sheet 3.0) has what looks like a key shaped hole, but it appears to be in a cover for the seat riser, not the actual floor.
My '51 3011 has a round hole in the bottom of the depression under the seat (in the floor proper), which is for drainage.
Can you post a photo of what you're talking about?

The drain makes sense. Just seems like an odd shape for it. Looks like something is supposed to go in it.

Maybe it's supposed to have a plug in the round part to keep road spray out like Tim suggested. It would still let water out of the slots off to the sides.

I have a round hole in the center underneath my seat; and in my case that area is sloped inwards (like a drain). When I was prepping for the floor repairs I power washed the interior and I can state with certainty that it works effectively like a drain, although why you would need one under there I'm not sure. I put a rubber plug in mine (they had the right size at NAPA).

Picture shows where it is but doesn't do the slopes justice, IIRC it's about a 1/2" hole.

That hole came in handy after I bought my '48. I took it to a car wash, removed the seats and used the car wash wand on the interior.

It could well be a part of the "Cab That Breathes" deal. It would allow air to flow in an area which is otherwise somewhat enclosed.

Interesting GM would change up the die cut for this part. Yours and Klhansen are round holes. You’d think for ease it would’ve been the same.

I like the “cab that breathes” line. I’ll tell my wife that the next time she complains about all the air movement in the cab.

Could it be for a Jack securing fixture?

That's what I'm thinking....

Plug like this one? 55 1st.

Don't know either. The Chevy and GMC trucks I've owned all had round holes. One came with the factory jack, tools, etc. The jack would only lift the truck a few inches, but it was there. They were not held in place by anything in that hole, though. They were in a heavy waterproof canvas bag with a cloth tie strap with GMC on it that just lay on the floor.

My 53 had such a hole believe it was for a rubber anti rattle part for the long rod connecting the seat adjusters? Truck is long gone so can't verify.

Different deal. That anti-rattle grommet plugs into the seat frame itself to support the rod. About 6" higher than the floor.

I was working on my 55.1 today and the seat was out, and I recalled this post. Hope it helps. Can't find anything on number. Good luck to all.

Thanks for sharing that pic. A little web sleuthing located this offering from Steele Rubber - Utility Plug. In the details it says it replaces original part number "4562300". A click on the vehicle application list shows a long list of various 1940-60 Buick models. Perhaps it was just a common GM item??? Unable to get into GM partswiki search this morning due to server issues, so can't do much more research through that way.

Anyhow, more fuel for the conversation - lol!