Blind concrete bolts

[luvrbus]

Kwood I am not a MCI person but can you not reach the bolts from the fuel door the MCI 8 I owned had a small stainless open box that could be removed to reach the bolts

[Blacksheep]

You guys can say what you want but MY lag bolts are not coming out in a collision. I say this because I am thew one that put them in. They did NOT go in easy! I used a 1/2 inch drive ratchet with a 3/4 inch socket and then it was still hard to get them thru the 2 pieces of 3/4 inch thick hard plywood! I'm talking about hardly being able to turn the ratchet hard! Squeeky hard! In fact at one time I thought I was going to have to use a breaker bar! 8 bolts took about 1 1/2 hours! Trust me, they aren't coming out, besides the seat belts are bolted to the frame and if anything stupid happens, they will hold the passenger AND the seat!

BS

[H3Jim]

Even though they were difficult to get in, I bet an accident the lags in wood would still pull out.  I pray that we never find out.

[Airbag]

A backing plate is a good idea and better than just large area washers. If you can trial fit the assembly and be sure all your holes line up then some liquid nail or some other similar adhesive should be fine. After all it is simply just to hold it in place in case you want to remove the seat right?

I would be cautious about tapping the plate. You want to be sure you have enough threads to do the job, If in question you can weld nuts to the plate to be sure. Another option is nut plates that can be riveted to the plate. Either is fine.

[wvanative]

You guys can say what you want but MY lag bolts are not coming out in a collision. I say this because I am thew one that put them in. They did NOT go in easy! I used a 1/2 inch drive ratchet with a 3/4 inch socket and then it was still hard to get them thru the 2 pieces of 3/4 inch thick hard plywood! I'm talking about hardly being able to turn the ratchet hard! Squeeky hard! In fact at one time I thought I was going to have to use a breaker bar! 8 bolts took about 1 1/2 hours! Trust me, they aren't coming out, besides the seat belts are bolted to the frame and if anything stupid happens, they will hold the passenger AND the seat!

BS

Well As I see it lets say you went with the lag bolts with the seat belts bolted to the frame, I'm not sure about the weight of the seats but I'd guess 100 to 300 lbs, add the weight of an average person 150 to 250 and you could have a total weight of from 250 to 550 lbs. If the bolts failed but the belt held I would hate to think of the G-forces exerted on the person in that seat, and with the possible weight behind it you could possible cut them in half. Maybe  someone could run some numbers on what kind of forces at driving speeds you might get. If it were me I'd want it bolted to solid steel.

Ok guy's Blacksheep might have something going here that will require a test with an old bus. and of course a test dummy. First Who wants to be the dummy LOL.

WVaNative

[JackConrad]

A standard nut thickness is equal to the diameter of the bolt it is made to for (a 1/4" nut is 1/4" thick, a 1/2" nut is 1/2" thick, etc.).  We welded 1/2" plate steel to the bus frame before installing the wood floor. 6 holes were threaded for 1/2" fine thread bolts (4 for the seat pedestal ands 2 for the seat belt). 3/4 plywood sub floor and finish wood floor was installed with oversize holes at each threaded hole.  Seat pedestal and seat belts were then attached with grade 8 bolts.  Less would have probably been adequate, but  this was one place I not going to take any chances.  Drivers seat used OEM bolts and pedestal. OEM was 4  1/2" fine thread bolts through framing under driver's area with washers and self locking nuts.  Jack

[Blacksheep]

Jack sounds like you did a great job as always and went the extra step/s!

BUT...

I swear some of you guys crack me up! If you spent even half the time on your bus as you do pondering over what is right and what is wrong, you might eventually have a running bus or at least one that is liveable!

G-forces? This ain't a friggin nascar racer were talking about! Were talking about a 30k lb plus vehicle that is good to get out of it's own way! Heck half or more of you don't even use them to get them moving!

I guess these lag bolts I used that are NOT coming out are in the same catagory as the waste tank I "hung" from my upper frame in my bay! That WAS supposed to come out from all the sloshing and fall somewhere in the middle of the interstate and wind up killing a family of four! Guess what? Nobody killed in the last 5 years and being that it's aluminum, which was a definite no no, there has been no leaks of any kind!

I think sometimes you guys need to use a little common sense and  better judgement as in look outside the box? Take the blinders off and get the bus done and ENJOY life as it is!

BS

[Don4107]

Ace,

It is clear that you simply don't grasp the physics of a collision.  You are old enough to decide if you want to mount your seat with wood screws.  (From your description, improperly installed wood screws, wrong size pilot holes.) If you want to be the first one at the accident to get a real close look at the pavement, that is your choice.  Subjecting a passenger to that is another thing. 

Recommending it to another is irresponsible.  Kevin was not sure so he asked.  Kudos. I think Kevin is on the right track to mounting his seats safely. 

It may take me a little longer to get my next bus on the road, but at least I will have the satisfaction of knowing that I did not knowingly cut any safety corners to get it there.  In the mean time I will still occasionally sit in my properly bolted down drivers seat and make Detroit sounds with my lips while hoping nobody gets in your way out there on the highway causing you to test you alternative seat mounts.   

Don 4107

[Lonnie time to go]

I know I am very new to this forum.  I post several Questions to the members for there opinion.
I have appreciated all the knowledge from others who know more that I do. I must say I do not want
advice that will { even a little } put my wife and kids at risk. For someone to recommend lag bolts in a
wood floor to hold a seat and safety belt is just plain wrong. The cost of grade 8 steel bolts along with
a piece of steel is only  a few bucks. I work in the construction field and can say in no way shape or form
should lag bolts be used in a wood floor to hold a seat or seat belts. Wood expands and contracts with
the weather. Posting what you may have done is one thing. Telling others it will be safe with such attitude
is just plain not good.  I am surprised that you didn't use duck-tape to mount your seat.

[Blacksheep]

Duct tape? How did you know that I used that to hold my ceiling up? You guys know all the tricks! Can't get anything past any of you!
BS

[cody]

I was curious on the lag bolt idea so I posed the question to a friend of mine that is a structual engineer, and another friend that does accident reconstructions for the state police, they didn't know either but said it wouldn't be hard to find out, we used 1/2 inch lagbolts, and screwed them thru 2 thicknesses of 3/4 in plywood and on a vertical pull it only took 475 pounds to pull them completely out, on a 30 degree angle (thats what he figured the frontal impact of a crash with a 40 percent decrease in speed within the first 1.5 seconds, the guy even stated the G force created by the simulation of rear ending a car at 55 miles per hour assuming the car was going 30 miles an hour and the bus traveling at 55 miles per hour) the pounds needed for that situation increased to 515.  Their opinion was that even without impact, the force generated by hard braking could turn the seat into a launching pad, at the very least it would "most certainly" fail to remain secured.  I posed the next question to them, what would happen if the seat belt held, their response was that it would cut the person in half easily and that was without impact, only hard positive breaking of a 30,000 bus traveling at 55.  I felt that these 2 guys would be qualified to answer the question and that is the answer they gave, whether it's right or wrong doesn't matter, they just gave a straight forward reply using their knowledge base of their particulare fields.  Their opinion that to do that would be suicidal at the very least, so for whatever it's worth, thats the answer as seen by them.