Frame Crack - Cut and Weld or Steel Over Damage

[ZombieK5]

On my 1990 Silverado I came across a frame crack where the torsion bar crossmember is located. Would it be best for me cut out the damaged area and weld in a piece in place or would it be more appropriate to simply weld over the damage with a much larger piece that is welded to a meater section of the frame?

The images below show the damage and also a piece of steel plate in place. I can just weld this in place....or cut the frame and weld it in.

Thoughts??

 

[Blue85]

I would grind out the crack, re-align that steel, weld it up, then weld in a reinforcement plate. Angle stock would make it even stronger. In addition to perimeter weld, you could drill holes for plug welds (although overhead welding is more difficult). I think the problem will be that any proper welding in that area will melt the rubber crossmember isolator and getting that crossmember out adds a ton of work. Could it be safely jacked up off of the frame rail with the torsion bars still attached? This would also give opportunity to reinforce the top and bottom.

 

[83ChevyK5Blazer]

Drill the end of the crack, grind it out and beat it back into place. Weld it up, put a plate over it and weld that in.

 

[ZombieK5]

I would grind out the crack, re-align that steel, weld it up, then weld in a reinforcement plate. Angle stock would make it even stronger. In addition to perimeter weld, you could drill holes for plug welds (although overhead welding is more difficult). I think the problem will be that any proper welding in that area will melt the rubber crossmember isolator and getting that crossmember out adds a ton of work. Could it be safely jacked up off of the frame rail with the torsion bars still attached? This would also give opportunity to reinforce the top and bottom.

I am able to use a tripod support Jack to actually lift that side of the Cross brace off the frame. My plan was to put a sheet of thin Steel in there as a heat shield. I'm literally of actually cutting out the section in welding in a new one. Where the crack is the steel is paper thin. It cracked because of corrosion and stress not just stress alone.

 

[ZombieK5]

Drill the end of the crack, grind it out and beat it back into place. Weld it up, put a plate over it and weld that in.

One of the big issues is the crack is paper thin. It formed because of corrosion and stress not just stress by itself.

 

[ZombieK5]

I would grind out the crack, re-align that steel, weld it up, then weld in a reinforcement plate. Angle stock would make it even stronger. In addition to perimeter weld, you could drill holes for plug welds (although overhead welding is more difficult). I think the problem will be that any proper welding in that area will melt the rubber crossmember isolator and getting that crossmember out adds a ton of work. Could it be safely jacked up off of the frame rail with the torsion bars still attached? This would also give opportunity to reinforce the top and bottom.

You can see how paper thin the crack is. I lifted the cross brace up to show the crack on the side.

 

[83ChevyK5Blazer]

Wire wheel or sand blast it clean, fix the crack and weld some flat stock down the frame flange, drill it for the xmember bolts.

 

[ZombieK5]

Wire wheel or sand blast it clean, fix the crack and weld some flat stock down the frame flange, drill it for the xmember bolts.

I'm thinking I'll cut out the damaged area with a small two inch by 2-in piece of plate steel and weld that in then I will put the existing 10-in piece of Steel you see in the pictures on the bottom of the frame and weld that into place.

 

[Blue85]

Frame swap it is then

The key is to not leave stress risers in another section of thin frame. That's why you often see diamond or tapered shaped patches.

 

[sweetk30]

no need to frame swap it . .

jump down the rabbit hole and solid axle swap it and add in some angle iron in this area to beef it up and be done .

all good points on fixing it in here already . but from a rust belt for life guy you need to stop now and look over the whole frame before you dump money in to it .

gmt400 88-98-00 stuff has 3 spots i have seen . front frame horns / end of boxed section under firewall / and rear cab mount- 1st box mount area of frame collects junk in the bracket pocket and its junk .

and a air hammer with a button head to rattle the questionable areas for solid or to thin is a great tool to have .

 

[ZombieK5]

Frame swap it is then

The key is to not leave stress risers in another section of thin frame. That's why you often see diamond or tapered shaped patches.

So make the ends of the patch jagged? Makes sense, I do the same on boat fiberglass repairs

 

[ZombieK5]

no need to frame swap it . .

jump down the rabbit hole and solid axle swap it and add in some angle iron in this area to beef it up and be done .

all good points on fixing it in here already . but from a rust belt for life guy you need to stop now and look over the whole frame before you dump money in to it .

gmt400 88-98-00 stuff has 3 spots i have seen . front frame horns / end of boxed section under firewall / and rear cab mount- 1st box mount area of frame collects junk in the bracket pocket and its junk .

and a air hammer with a button head to rattle the questionable areas for solid or to thin is a great tool to have .

Frame Horns are good.

Replaced 4 out of the six body mounts. BOTH rear mounts, ONE mount under the firewall and ONE radiator support mount. Put in Po;y body mounts and 3" body lift kit.

Want to do solid axle swap but not yet. I seriously need to get this truck off the lift and start on my 77' Blazer again.

 

[Handy1]

So make the ends of the patch jagged? Makes sense, I do the same on boat fiberglass repairs

Radius the end of the patch.

 

[scouthead]

Wire wheel or sand blast it clean, fix the crack and weld some flat stock down the frame flange, drill it for the xmember bolts.

This is my vote.

I would:
-Clean the living daylights out of everything.
-if you can find the “end” of the crack, drill a 1/4 inch hole right through the tail end of the crack.
(I’ve been told this distributes the stress and helps prevent the crack from continuing)
-align the frame, weld the crack as best you can, and do not weld over that hole you drilled.
-grind everything flat. find some scrap steel and make a patch that runs well beyond the damaged area on both sides. Take some time to plan how to avoid stress risers. Look at where the frame wants to flex, and where the hard attachment points for crossmembers are restricting that… try to avoid creating additional places where hard stops create stress risers. Cutting the ends of the patch at a 30-45 degree angle… and consider NOT running a continuous bead around it. Corrosion is a concern, but I would think about running 3/4 inch bead, then skip an inch, then another 3/4 inch weld, then skip… etc. and I would probably drill 3/8 holes in a few places) in the middle of the patch, but in the areas between the welds) through your patch and plug weld to the frame. If you already have to drill the patch for existing bolts, this accomplishes the same thing getting both layers attached in the middle of the repair.

I’ve also been told to avoid continuous weld beads on the bends of the frame- so weld on the flats of the horizontal and vertical surfaces… but a long and hot weld on the edge may weaken the frame in that area.


Other than that… I would make sure your patch isn’t overly thick/heavy material compared to the frame material. For example, If the frame is 3/16 thick, cut your patch out of 1/8th inch material, and then angle and taper the ends to avoid stress risers