Sounds to me like the bolts sheared. Like Jim said, possibly from over torquing. Use the torque specs, and a little thread locker.
A pet peeve of mine: Hardware Gorillas; people who think tighter is always better. Ironicly I have "gorilla proof" hex wrenches.

Daggerdoggie: probably from accumulated fatigue on the metal

DBAX: That is the coolest graemlin thing ever.

that is kinda cool...but again dont post for pics....i said you wont get them until i get my X back in working condition...not driving 2 hours out of my way for pics...so dont post for the pics anymore please. maybe i could have made the title a little different...sorry but something broke. The bolts didnt break from what i saw...no shearing action. They jsut came clean out of the horns and took some metal with them. How about this...we leave the thread alone and I am guessing around Thursday I wil lbe getting my X back from the shop (Earliest!) By then if I have it back in CT that day I will take pics of the bumper and frame as is and you guys can come to your conclusion as to what happeend then.

Being there, seeing the situation in detail both when it happened and the next day when there was more time to examine it I have a couple--non-important--things to add here....#1--Dom(cobain913) has no ill intent here when he says his bumper "broke"...he doesn't mean the bumper snapped in half or anything like that....he just meant that something went wrong and the bumper is not operating the way it was intended...can't imagine there was any blame implied...#2--Jim...to quote you "This sounds like the threads simply pulled out of the ends of the frame horns and the bumper rotated down a bit. If the threads did pull out the ends, it *would* rotate down and point downward some bec the side bolt holes are slotted." This is EXACTLY what I believe happened...there was no twisting or damage to the frame horns, there was no obvious movement or damage to the side bolts and it simply looked as if the bolts to the front of the frame horns had pull out of their holes, doing some damage to the bolts on their way out....the likely repair I would imagine--though other more knowlegable(pretty much 99% of the people out there) people may have a better solution--would be to redrill the holes, use the next bolt size up, and confirm the torque setting...

I didn't realize their was a torque spec on the bumper. I read the directions and everything when I installed it. Maybe I just overlooked. Anyways, I just used an impact on my bolts. I imagine they are pretty snug on their... I hope not too tight now.

OK - it sounds like the frame horn bolt strip from overtightening, and the subsequent pivoting of the slotted rail bolt points is it.

The stock parts are a bit delicate, and just like putting together IKEA furniture, if you use too much force, the stock parts can't take it, and can break, strip, warp, etc.

That's one of the reasons I didn't use the stock frame horn end bolt holes when I lifted my winch bumper, I welded an "L" on top of the horns, and bolted through that, and as the horns themselves were a bit wimpy, I also welded a brace between the horns to shore them up, especially against torque loading from potential off angle winch loads, etc.

Our confusion here is that articulation is important, even in conversation.



Saying something "broke" implies that it, well, broke.

If what was meant by "it broke" is that "What it's attached to broke", that's fine, its not like Cobain is famous for clarity of speech....hell, most of the time he gets kudo's for performing opposable thumb and forefinger tricks.



By process of elimination, and reliable eye witnesses, we figured out what he would have said had he been better at this sort of thing.



The morals here are:

To take the pics BEFORE travelling 2 hours away..

...and to take it easy on stock mounting points, they were not designed to take non-stock forces.

And to add to TJ's...

Use freaking loctite on important bolts. The bolts may not have stripped out; they could have just simply loosened up over time. There shouldn't ever be any force in the sideways direction; at least not nearly enough to strip out the bolts, considering they're perpendicular to the bumper... My guess is they loosened up a bit, 'cause there wasn't a lock washer and/or loctite involved.

haha unfortunately this is true...I do ahve one pic on my phone that is a shot of the frame horn but i dont know how to upload it onto my computer...so unless somone can tell me how to do this I'm SOL...I have an LG phone (the one with the sxivel camer on top) and Verizon service...I am really bad with figuring this stuff out so if you want to tell me quick i can get that pic up

Same kind of thing happen to a couple of owners of ARB bumper owners who winch on 2K’s. Ned being one of the ones I remember, I saw 1st hand what happen...his bolts where torque down properly yet the frame horn holes ended up elongated after a normal pull. He eventually went with the extra bolts on each side like Jim suggested and also welded on a L type bracket on top and did’nt have any problems after that.

When I put my winch on my ARB I just went with the extra bolts on each side and haven’t had any problems but without them the bumper is not secure enough for pulling IMO.

Brian

Do we need to put in more than the 6 bolts if we winch/pull with the shrock bumper? I thought about drilling 2 more holes for 8 bolts total through the frame horns.

You don't want to do that.

suspect2 i wouldn't do that, it what designed to have six bolts and not 8 and it was also designed to have winches inside and pull stuff. If it couldn't, the people at Shrockworks would add some bolts or modify it if it was a problem. If ur bumper came out of the car then it was prollly put on wrong.

JUst follow the directions!

I don't think there's any harm in adding one hole per horn,.... once the bumper is mounted with the end horn bolt, and the slotted side bolts, there is an extra hole on the frame mounts of the bumper that isn't slotted....drilling a hole through the frame, through those holes, would lock the mount so it would not pivot.

I believe that was always an optional mounting point, so Jim already has given the option if desired.

I'm not sure if the frame mounts on every year's bumper have those extra mounting holes or not, but, if you have them, seems to be an easy add-on...and, if not, you could always just drill through the bumper and the frame, and then slide a bolt all the way across.

I haven't done this, but then again, I like torque wrenches, and I appreciate the concept that if you torque something past the strength of the thread system, it can strip/be weaker than if you were more gentle....more isn't always better.



I also like lock-tite, etc....so my shit don't fall off.

is it ok if u dont do this

cause when i ordered my bumper i asked the guy on the phone if the bumper came with everything it needed, and he claimed it did and it would come with 6 bolts and all that stuff, but he claimed that is all u need.

You look at it like this. Most are running 6 bolts and it's not like you have hear bunches of horror stories about the bumpers ripping off. So I am sure 6 is fine for most applications. On the other hand, drilling two holes and buying two bolts isn't a big deal, so why not do it for the extra security?

As others have said, over tightening is a bad thing. This is the reason there are torque specs for things. Stressing threads are just as bad as not tightening the bolt/nut.

My number of 70ft lbs comes from the typical torque specs of trailer hitches, not just on X's but most vehicles.

Adding bolts may not be a solution. You could make it 8, 10, or 12 and then you have frame horns like swiss cheese, and just as strong. There can also be a lot of torsional stress and upwards stress from hitting rocks with the bumper. Which I have done a fair amount.


As you can see, I even bent my bumper at the hole where you can reach in to move the cluch on the winch. Mine has held up fine, and I have used the winch many times as well as the tow points. Following torque specs is important. when you torque a bolt, you are stretching it to a point, when you over torque it you strech it too much and weaken it.

Sometimes, things just break on the trails.

NICE PIC!!!!!

Hey guys, late chiming in but I was the other person that had problems that day with the bumper mounting points. The reason the bumper tiltd without doing damage to the other 2 bolts is because the other bolt holes are slotted. I have a pic. Though the bolts didn't pull out like Cobain's, it was on it's way. I plan on banging the warped matal back flush and adding more bolts like Jim said. I think why winching doesn't do the damage but being pulled does is the load is more centered on the bumper when winched (load is spread more evenly) where being pulled from one recovery point puts all the pretty much load on one side. I winched myself quite a few times later that day and no further damage. I had a TJM on my Frontier and used 1 recovery point and no damage what so ever.

Another late chime in - The frame horn threads are not that strong. In the course of mounting my Shrockworks bumper, I tightened and loosened them probably half a dozen times trying to get things lined up perfect (I'm anal). In the course of doing so, I stripped out 1 side. I wasn't even torquing them that hard - those threads are really weak. My solution was to drill the hole out a smidge and put a nut on the back side - there is just enough room to slide a nut up behind there (at least on my frame horns there was). The threads are weak, so be careful.

i recommend if you add one more bolt or maybe even two that you sleave the frame. box it so it doesn't crush. i did this when i lifted my ARB for the 2"BL.

Can you explain what you mean by "sleave the frame"??

Those threads are weak. After I had taken off/put on my Shrock bumper numerous times, I got the bolt on the frame horn end driver's side crossthreaded because the threads had gotten so thin and I haven't fixed it yet.

That's a good idea about the nut - I'm going to see if there's enough space on my Frontier to fit a nut up in there. I'd like to still do the "L" brace on top of the frame horn end like TJ did, but damnit I don't want to take off the bumper again!

-Bp

I believe that is when you cut some tubing and weld it into the holes you drill through the frame horns. Stormtrooper/The BN Guy over on NOR also did this when he raised his bumper to match his body lift:

Shrockworks Bumper Relocation After Body Lift

This is another thing I might do if/when I take my Shrock bumper off.
Right now I just have two pieces of 1/4" thick steel 2" wide by 6" long as a backing for the bolts I drilled through:



-Bp

Exactly

nice job on the frontier. very clean.