'99 seat mounting bolts
 

OK, so Im close to tackling the floor pan I need to replace, but looking at the bolts that hold my seat to the cross member (drivers side), Im pretty sure those arent going to come out without getting ruined as they are RUS-TEE! So, before I am screwed completely and unable to put my seat back in, does anyone know what I need for bolts? Size, grade, etc.? Thanks a ton!

Best bet would be to drill them out and get new STAINLESS hardware.

At that point you don't need to worry about size so much. Just head up to the hardware store and get close size.

There is only the rear bolt that sticks outside that you will have to worry about. The two front bolts are fine since they don't go outside the cab and the rear stud on the right should be beefy enough to take an impact... I would say for the rear bolt... wire wheel it, soak it in penetrating lube and try it with a socket. You can use heat but be careful!

P.S. the bolt sizes are 13mm, the nut is 18mm.

Maybe he'll get lucky, being a 99 and much newer, but my 87 didn't play so nice.

Either way, use stainless and you'll be thankful.

maybe... I broke the driver's side bolt... I did the procedure mentioned in my post for the passenger side...

Just be careful where you get stainless hardware. Depending on where you get the hardware if you get claimed "grade 5" or "grade 8" stainless fasteners they will rust as bad as it's all steel counterpart... been there :bangin:

OH, I plan on going the stainless route, but Im just wondering on the size because, like I said, the 2 in the front are NOT going to come out nice. I can only see the head of them, and Im pretty sure when I put a wrench to them they are going to snap. The firewall has been leaking PROBABLY since the day I bought it (June 15, 2002) and everything down there is rotten, including the cross-member that the seat bolts too and the bolts themselves. I appreciate the help, Ill post pics when I get at it (couple weeks), I just want to be TOTALLY prepared in case.

My plan is to pull the seats (both front) and the carpet, etc., and see what the total damage is and go from there. I just dont want to break the bolts and NOT be able to put them back in and run to the store. My truck is down right now (doing a complete rebuild to it) so I NEED to be able to put the seats right back in.

Again, thanks a bunch.

The Correct size bolts are 13mm M8 bolts and the nut is actually a 11/16 (yeah, I know, right). 11/16 is smaller than the 18mm. Although I never had a problem with an 18mm, it is loose. 11/16 is 17.4625mm and fits correctly.

Use caution in considering the use of stainless steel fasteners. They typically are not as strong as high strength steel fasteners (grades 5 and 8) and for safety critical applications such as holding a seat in place you are better off going with carbon steel hardware. Stainless steel is also subject to galling and seizing, a process where small oxide particles of the metal jam up the threads and you either can’t get it properly tightened or it is impossible to remove. Also avoid mixing different material fasteners such as carbon steel and stainless steel. This can lead to problems of galvanic corrosion due to dissimilar metals. If you use stainless it is recommended to use a high quality anti-seize compound. It is not cheap.