Check your U-bolts!!!!!

[M1031]

As I was working under Big Max, I noticed I have not one, but TWO broken U-bolts that were holding the body to the chassis on the driver's side. I haven't checked the passenger side yet. There is a school bus dealership near where Big Max is being modified. I'll have pics either tomorrow or Friday.

Seriously, as you do your semi-annual inspection check the U-bolts to be sure they are not corroded, fractured, or missing anything (like a nut).

*Edit*

Here's the pic of one of the two broken u-bolts:



Update - I found some stress fractures in the supporting brackets under the driver's area where they welded the brackets to the floor sheet metal. I'm planning on acquiring a gas welder in the fall (Octoberish) to weld the fractures back together. Meantime, I'm replacing the u-bolts with new ones today.

[bus-ted]

Your post, M1031, brings up a question I've wanted to ask for some time, and to hell with being embarrassed by it. Anyway, I own a thomas built bus, and to be honest am not quite certain how the bus body is held to the frame except for two places up near the driver's area, where it's bolted- not with u-bolts, but with what looks like 1/2" bolts through a bracket that is bolted to the frame(I'll grab a pic tomorrow). Surely there are more points of attachment? To me, it looks like the floor panels just rest on these rubber spacers between them and the frame, but I know that can't be the case.

Any Thomas owners out there that can enlighten me? (I hope this doesn't qualify as post jacking, but I can start a new thread if need be.)

[frank-id]

The bolt pics look like the bolts are under size. The bolts should be at least 3/8ths diameter. Take the bolts to a truck shop that custom bends the u-bolts. The bolts are not expensive. The new bolts are supplied with washers and special nuts. Ask and learn. Do not make statements but allow the shop mechanics to give you information. Breaking a u-bolt is not uncommon. Ya did good to find this easy fix. Frank

[frank-id]

Get under the bus and make some new discoveries for your bus. Thomas buses are good buses. All buses are good buses. Tell all the Thomas bus folks, how many frame to body bolts are used. Frank Yep, I have a Thomas too...

[bus-ted]

Hey there, Frank in Idaho, I love my bus, and I spend/ have spent a good bit of time under it. I'm not implying it's anything other than a good bus, I'm saying that I only see two actual bolts holding the bus body to the frame. Are the others hidden? I wish I knew how to make drawings over the computer, then I could explain myself better. As it is , tomorrow I'll take a pic of the bolts I DO see, and maybe someone with more knowledge could help me with some actual info, or point out what I'm not seeing, not taunt me. Thanks.

[the_experience03]

You are buying actual u-bolts, correct? We had a guy come in the shop not too long ago looking for some threaded rod he could bend into u-bolts. U-bolts are made of special steel and the threads are rolled, not cut. Speaking of which. this also means you need to measure the diameter of the straight shank, not the minor or major diameter of the threads to be accurate. Frank was dead on with the special nuts comment.

[M1031]

Ok, a follow-up. I found out the u-bolts in my Ward are 7/16ths. These u-bolts are 1/16th under size. I replaced the broken ones with 1/2 inch u-bolts. I bought four other 1/2 inch u-bolts for Max. There are a number of J-bolts used as well under the bus. The Js are hooked to have the tops facing outside the frame with a straight bar bolted to the J and the body. I checked those out (1/2 inch) and they're fine. I also found stress fractures near the front u-bolt inder the driver's floorboards. I'll weld that up in the near future.

[M1031]

I counted 14 total J bolts securing the body to the chassis. Here's what they look like - Nice and beefy (or gerthy):

From the side facing out to the side of the bus:



Here's how it hooks under the chassis, note how thick the hooks are:



This is what the whole thing looks straight up from the bottom of the bus:



Now you know another big reason why I bought this bus besides the maintenance. I trust this bus to handle anything I throw at it.

[bus-ted]

So, you have 14 total j-bolts PLUS another 4 u-bolts, is that correct? That's a helluva lot better than this old thomas of mine.
I'm still in disbelief. Seeing the way yours is set up, though, makes me think I should go that route. An easy fix, and a big load off my mind (and on to the bus!).

[M1031]

14 J-bolts and 6, not 4 U-bolts, so that's 20 bolts of one description or another in total under my bus. Max could be a tank!

[Will]

My '91 Thomas has zero u-bolts. The body is clamped to the frame with clips inside of the frame rails. Look at your again and see if you have them. In this picture of the box my 50amp cord rides in, you can see the clamps right at the top of the box.

[M1031]

Yikes Will!!! That looks a bit scary to me. I'd need to know how thick and effective those clamps are. I'm curious to know how thick they are whenever you get a chance.

[hoser]

Check your rear axle U bolts too I drove quite a while with a broken one, I kept hearing a clunk when braking hard and could never pin point it until one day I noticed the U bolt broke, a local axle shop made me up 2 news ones I installed the one and kept the other as a spare, spring guy said they break all the time.

[wheeler]

working on the conversion shortly after getting my '91 bluebird, over a period of about a week we would hear these loud bangs. sure enough, it turned out to be the 4 front u bolts. all broke in the same place. a couple of months ago, parked in a buddies driveway overnight, the same bang. this time we knew what it was and got a new ubolt on b4 the rest went again. cut the old one off with a grinder. lucky it's a cheap fix.
*

[RUskoolietailgater]

I don't know if it is a U bolt but we have been riding without something on our axel for 2 years now. Mechanics tell me it is $20 to replace and helps the body not slam down on the axel when hitting bumps. Wondering if this is it...

[cschlessman]

its called a bump stop.
Chuck