99 4964 Frame Crack Suggestions

Nope they're definitely steel, and there's no boltholes to "waller" out

I've attached a screenshot. This isn't the exact crossmember, but the design is almost identical. It looks like they bolt the flanges on the truck, square the frame then weld around the eyes to secure it. I looked at mine outside, it's only welded all the way around the eyes you see in the picture, but gouging those apart would be creating more work I feel. I'm going to do some calling in the morning and see what I can get my hands on for material. At this point I feel installing as big of an insert as I can without hitting the crossmember, and cutting the ends to 45 degrees may be the way to go. I can add a few bolts, and certainly monitor the outside frame rail to ensure cracking doesn't reoccur. The only shortening necessary would be torque rods, which I can do. On the right side rail the crack is after the rear crossmember, so I'd only be able to come to it anyways.

 

I hear you, and certainly value the input. I just don't see a way of doing it that won't potentially open up another can of worms. Kinda wish I'd found these cracks sooner.

 

Here's another possibility for you, that you may or may not be interested in doing.

You could run new frame rails in front of the tandems to a spot where you are exactly between the cross members. Then the only thing that you have to change is to shorten the crossmembers up and go past them with your insert and have it cut on a 45.

Then you have new frame rails so you don't have to worry about your cracks, and you only had to change your two crossmembers without changing a lot of other things. Depends on your situation. You could also get a cut off or get the frame rails from the same exact truck with the same exact suspension, and that way you really only have to drill for the insert.

I don't know if it would interfere with your suspension, but you could even have an outer frame rolled and run that right up to your cab.

 

Thanks for the input. At this point I don't think there'd be any value in splicing the frame with a new one. I'd be introducing two different areas for fatigue (vertical vs horizontal cracking) and a heck of a lot more work/money too. The rest of the suspension is intact with no cracking, so there's no point in going that far in. If the suspension did ever completely fail I'd likely be swapping it for an AR2 setup out of another truck.

Rolling on the outside isn't an option either. It would interfere with all the rear suspension.

I really don't like the idea of not inserting at least the full length of the drivers, so I'm thinking the best solution may be to cut the rear crossmember in the middle so it can be removed, shorten both pieces by 1/4", then reinstall and weld in-truck with a fishplate over it. That would get me the necessary clearance for the inserts, and also allow me to run full length inserts.

The forward crossmember is a tube-in-socket type deal. I'm pretty sure I can gouge the welds off it and simply re-weld.

 

If you don't run an insert inside the frame rail it's just going to crack again wherever you weld it.Any type of heat to a frame removes the temper in that area, hence the reason for the reinforcement. I would extend at least 12" on either side of the crack. Same deal with the crossmember, wherever you weld it, it's just going to crack.

 

Correct me if in wrong, but I believe the frames are heat treated, not tempered. It they were tempered they'd shatter after a certain load point. Heat treating makes the frame more flexible, but with a memory so it springs back after load. I don't believe the crossmember is heat treated or tempered. Looking at it and the current WS bodybuilding catalog, they indicate that it can be modified in frame with no consequences.

It can be preheated and post heated to relieve welding stress. That much I do know.

I think 1ft either way would be a minimum fix. At best I'd like to sleeve the entire drive section to prevent this from happening again any time soon.

Either way, I'll be making a decision tomorrow. I may just end up having a local truck shop do it if they're reasonable enough. They have half the kit there anyways.

 

I have never seen crossmembers like that but they are even easier than the bolt together style.

Just measure the outside to outside of your frame, remove the crossmembers and cut the welds loose that hold the flanges to the crossmember put your insert in and then reweld the crossmember tube at the correct length. All steel makes it a pretty straightforward process.

 

If you plan on keeping this truck spent the time and money to insert the frame as far back and forward as you can afford. I've seen those type of cracks on dump trucks before. Usually near the end of the trucks useful life I've seen dump trucks that have a third layer a foot long or so where the box pivots at the rear too. On the crossmembers you can get away with only shortening one end. Its only going be offset a 1/2" or so. There should be enough adjustment in the panhard arms to not need shorter ones. Western Star used to say one piece crossmembers were stronger than 3 piece. That was their theory anyways. Good luck on the job.

 

Thanks for the reply. Called dealer and they suggested the same. Insert forward to the drivers at a minimum. We'll see what our local job shop has to say about it, apparently everything channel related has to be brought in from the US now.

 

Just go to a steel shop that has a large break and have them bend you a pair of insert rails out of 1/4" T1. Should cost you less than $40/foot Canadian.