Are HD frames that weak and known for cracking?

[WarWagon]

Sigh another scrap metal rig. Says blows black smoke - well easy enough to see why.
Hint: it's a 1993.

Looking at the frame just behind the cab where the tow bed attaches the fix has even cracked through!

I used 2nd, 4th, and 5th at WOT getting away from that! Didn't want to risk stalling by starting in 3rd.




Smokes eh? Pretty clear why.



Inside the frame repair:

 

[Burning oil]

Never seen that before, is it a "low performance" mod?

Has oil going to turbo from OPS port too?

Like that frame, what would you do if you had a million dollars? Buy a new butt mine has a crack in it.

 

[WarWagon]

I bet it's a 6.2 replacement. So used to seeing that on my turbo 6.2's I forget what it means and overlook it.

 

[Will L.]

That frame is repairable. find a truck equipment shop in your area. If you pull the cab, the frame repair should be around a grand. If you are or know a welder, I can let you know more details.

I was a 50% owner of a truck equipment shop in the early 90's. We used to shorten and lengthen frames all the time.

 

[WarWagon]

That frame is repairable. find a truck equipment shop in your area. If you pull the cab, the frame repair should be around a grand. If you are or know a welder, I can let you know more details.

I was a 50% owner of a truck equipment shop in the early 90's. We used to shorten and lengthen frames all the time.

It's behind the cab in plain sight. So does the cab still need to come off?

I would be interested to know: What does the "proper" repair involve? This frame issue is the only thing having me turn this truck down as it's ideal for what we want to do with it.

Remove incorrect year turbo that is put to boost, not vacuum, and should be a spring can for a 1993, fix bad engine oil leak, and new cable and new parts on draw bar for 2nd car.

For a MT truck the proper turbo selection would be interesting.

 

[Will L.]

You have to make inside and outside gloves to fit the frame. Basically mild steel plate the same thickness as the frame, bent into a "u" shape. One fits the inside of the frame, the other outside the frame at least 24" long.
The edge of the flanges should line up together.

Cut the frame where it is cracked with a beveled edge on both sides. 100% welded, let air cool down. Grind flat for gloves to fit. Where the crack goes into the relief (and the oval hole). A piece of metal will have to be fit in to fill it and fully welded, then ground down. All the welds have to be peined. Nothing else can be in the way in between the frame and the two gloves. The gloves get bolted into place. You have to drill through the frame and the gloves with get bolted into place with three 1/2" grade 8 bolts and mechanical lock nuts on either side of the welded section. The bolts have to be 1/2" away from the flange in a diagonal line at a 45 degree angle. They should make a letter v when on the drivers side, when on the passanger side it should be an upside down letter v.

Where the tab that is bolted and welded on has to go. Repaired in similar fashion.

Whenever attaching a flatbed,or similar item to a frame, if the original mounts cannot be used, and needs to be tab mounted to the frame: the bolts need to go through the frame face. It needs to be half inch away from upper and lower flanges. The flanges are the top and bottom part of the frame including the round over portion. Never drill or weld the flanges and you won't have a problem. Also never drill or weld in between spring mounts on the rear of the frame. Technically there are exceptions to the rule, but it is too detailed to try to explain.

 

[GM Guy]

Its a 5 speed, you have to save it now.

What wheelbase? are you up for a frame swap?

you could get the OEM frame braces that were found on the 95+ units(maybe 94+?). It involves cutting the cab mounts off, as the braces have the mounts allready on them. I imagine this could be the outer "glove" and one would have to fab the inner glove still.

 

[Will L.]

Yes that is. I forgot about seeing those.

And for the future, the best way to mount a flatbed is 1x3 apitong wood strip between the frame flange and flatbed stringer frame with ubolts.

 

[GM Guy]

Yes that is. I forgot about seeing those.

And for the future, the best way to mount a flatbed is 1x3 apitong wood strip between the frame flange and flatbed stringer frame with ubolts.

Excellent point. I was going to mention that, but figured there was something I didn't know about rollbacks.

Around here, nothing is ever welded to the frame, either straps with bolts through them, or just plain u-bolts, and anywhere from a strip of belting cut to size, or thin strips of lumber.

IMO the welding of the bed to the frame caused the break in the first place.

 

[ak diesel driver]

X2

 

[uniquediesel]

The early HD's had problems with breaking the frame. Find a newer HD frame and get the re-inforcement plates that come on the 1994+ HD's. My rollback has these on it, as does my other HD.

 

[Ed HD]

I'm assuming it's because the frame and the flatbed flex differently, which is why the factory uses rubber mounts to bolt down the bed/cab? Our 08 GMC 4500 has some beefy looking lumber in between the frame and the cargo box.

 

[schiker]

Its a couple of reasons flex stress, point loading, and heat affected zone stress.

A roll back is a pretty harsh attachment and load on a truck frame I would think. Expecially if they get sloppy with loading crooked, on uneven ground, or funky retrieval. Could be some fairly harsh binding and buckling forces.

Have you ever slowly tried to stand on an aluminum can. If it is undamaged it can hold a little weight but if someone takes a stick and pokes the can it will crumple. Or a can with a dimple cannot support the same weight without crushing. The fame can be like that if a heavy load is placed on a small area like a small welded tab.