Check your bumpers! (1 Viewer)

[Squash]

Well, I've done it again.
Tried accessing a trail to a set of rapids to enjoy some ww kayaking and rhubarbed the SC'd 80.
The combination of ice and packed snow plus me being dumb called for help.
Normally my chains do it, but no!
Called a friend so we could grab the HDJ81.
A little snatch forward to prevent tipping when backing out and then the pull sideways and back to swing the arse end back onto the trail.
I always suspected this might happen as I did not install the bumper.
Luckily the two side to side braces held, welds all let go, but she did move, not allowing me to not drop the tailgate....hmmm.
So just finished taking the bumper off and will get it properly secured.
17mm inserts in frame rail, got one off with the impact and the other had to be cut with a grinder because it just spun.

 

[DancesWithMutts]

PICS

 

[Squash]

Only the sides held!
Welds or bubble gum failure. DS insert in frame rail also let go.

 

[BILT4ME]

That does not look like bubblegum welds and weld failure.

That is metal fatigue on the sections of frame rail and Heat Affected Zone (HAZ) failure.

Those are not bad welds. That was a hell of an impact. It is also very possible that since it was installed, it has had a LOT of those type impacts and that is what has caused the fatigue.

I would be interested to see another pic of the complete rear of the frame where the pieces were ripped out and broke of the frame rails.

 

[bencallaway]

Wrecked and rusted. Can’t really make sense of what you’re describing.

 

[Squash]

No worries, I will ensuse the new install gets reinforced as the bumper should be more than cosmetic.

 

[BILT4ME]

No worries, I will ensuse the new install gets reinforced as the bumper should be more than cosmetic.

View attachment 2263728

View attachment 2263752

Only those three points held it on?

No wonder it came off!

Should have had a horizontal under the frame rail and bolted up from the bottom as well as a plate on the outside of the frame rail on both sides, bolted through the rail.

Yeah, those were destined to fail due to how hey were attached. A bit of a side hit and all the bad ideas cm together.

Sorry for your loss.

Good luck on reworking it and reinforcing it!

This is one of the issues of home building a bumper and not REALLY understanding the fabrication and engineering design behind things. I'm sure this bumper looked impressive, but the attachment left a lot to be desired. Unfortunately, many of us here would have thought it was great as well until one really digs into analyzing it.

In all honesty, I probably would not have taken it off to redo it, just mostly because of "laziness" on my part. I would have put it off until the event of exactly what happened to you.

But now we can ALL think about it!

Thanks for your posts!

 

[leonard_nemoy]

That is metal fatigue on the sections of frame rail and Heat Affected Zone (HAZ) failure.

I have had a few very knowledgeable welders tell me that welding onto a vehicle frame is a bad idea because it will change the temper/heat treat of the frame leading to a crack or failure around the weld. I feel like this is a good example. And a good argument for bolt on vs weld on armor.

 

[jonheld]

I have had a few very knowledgeable welders tell me that welding onto a vehicle frame is a bad idea because it will change the temper/heat treat of the frame leading to a crack or failure around the weld. I feel like this is a good example. And a good argument for bolt on vs weld on armor.

Look at your frame and count up all the points that are welded to it.
What your welder is alluding to is the frame of a tractor trailer, not a Land Cruiser.

 

[BILT4ME]

Look at your frame and count up all the points that are welded to it.
What your welder is alluding to is the frame of a tractor trailer, not a Land Cruiser.

Respectfully, it does also apply to LC frames and any other pickup frame. They are not the common A36 mild steel that is not heat treatable anymore.

There is a very specific welding/repair procedure for doing frame repairs on big trucks (semis) as regulated by the DOT and it should be followed sorta closely for other frames. The other frames don't see the heavy loading the big trucks do.

If the frame welding procedure would have been followed here, the failure would have been much less likely. The biggest difference is that there are no re-pads around the flat bar welded in on the narrow axis. There should have been a pad (preferably round) that was welded to the frame rail, then the clip welded to that. Then, in a perfect world, a rosebud torch to anneal and even out the HAZ to temper the area around the weld in order to reduce the crystallization within the HAZ.

Oh, and BTW, it's best to preheat the weld area before you do actual welding on it in order to reduce the problems associated with HAZ cracking. Different materials required different preheat temps, and you really SHOULDN'T weld on them outside of those parameters, but most applications do. Hence, the need for CWI's, radiography, and X-Ray technology in welding inspection services.

FWIW....YMMV.

 

[Squash]

No worries it will be a tractor! Luckily the two side braces were bolted into bottom of the frame, mind you the inserts were pulled nearly through the frame. Those will get long extra plate.
Pics of DS frame insert and side brace

 

[george_tlc]

That damage has been some time coming. If you look at the steel where it 'ripped', there's a lot of rust already on the surface of the rip. Unless those pictures were taken some time after the incident...

cheers,
george.

 

[BILT4ME]

When you do your reworked version, also include a plate on the SIDE of the frame rail. That will help a LOT.

 

[dan1554]

Might look to an off-the-shelf (eg. 4x4 labs) bumper for inspiration on mounting. Like @BILT4ME says, run something parallel to the frame instead of coming in from the side. Those bolts probably got twisted out when the welds let loose, but Im not sure they were a point of failure to begin with.

 

[leonard_nemoy]

Look at your frame and count up all the points that are welded to it.
What your welder is alluding to is the frame of a tractor trailer, not a Land Cruiser.

Yeah, I have heard this argument from plenty of people... But none of them had master degrees in metallurgy. But both of the individuals that told me welding on a frame is a no no did have extensive educations on the matter.

Can you verify the process toyota used for welding the frames on an 80 series? Were they welded by hand using gmaw or smaw, or possibly welded with an automatic submerged arc welder or welded using a variety of other industrial weld processes? Did toyota heat treat the frame after welding? Also why grind off the paint and weld on the frame when it could increase the potential for rust when bolt on works just as well?

Just some food for thought. At the end of the day there are a lot of vehicles driving around the country that have had their frames welded on with absolutely no issues so it really doesn't matter lol.

 

[jonheld]

Both my 80s have welded sliders, but they were built and installed by an industrial metal fabricator. I've never been a fan of the bolt on options, but that's just me.

 

[dan1554]

My concern is always the burned off paint on the inaccessible parts of the frame after you weld to it. I still do it, I just try to keep it to a minimum and lean toward bolt-ons.

 

[Railwelder93]

I happen to have a good example in my garage right now. Looks to be a good design to me. 12 10.9 bolts will hold it on.

6 up from the bottom (factory hitch holes)
One passes through the frame from each side and clamps the frame rail with another loose plate.

4 into the rear cross member.

 

[Wompom]

I happen to have a good example in my garage right now. Looks to be a good design to me. 12 10.9 bolts will hold it on.
View attachment 2265861
6 up from the bottom (factory hitch holes)
One passes through the frame from each side and clamps the frame rail with another loose plate.
View attachment 2265865
4 into the rear cross member.

Is that a kit or homemade?

 

[Broski]

No worries, I will ensuse the new install gets reinforced as the bumper should be more than cosmetic.

View attachment 2263728

View attachment 2263752

The Biggest issue I see with the weld failure is the mounting points don't reach the top & bottom of the the cross number and theirs no triangulation. The non factory crossmember looks to be 2"x 4" .120 wall or 1/8" thick so if the mounting points don't reach the top & bottom it's like welding to a peace of 1/8" plate and with no sheering ( flat bar tying all the mounts together) or triangulation this bumper was destined to fail. JMHO