Replacing Weld Nut - TRD Pro Skid Plate

The rear two bolts for the TRD Pro skid plate are held in by nuts that are welded to the inside of a crossmember. These nuts can break off from overtightening using an impact/air tool, or from rust. The skid plate doesn't need to be removed for an oil change, but does need to be removed for a front diff service, when this happens you run the risk of a technician overtightening and breaking these nuts (I think that is what happened to me).

Once the weld breaks, its pretty much impossible to properly torque your skid plate due to the location of the nut being inside a cross member. The nut is also square, and doesn't properly fit in any metric or standard socket wrench (I found that 9/16 is the only socket that gets any grip on the nut).

Aside from the tightening issue, once rust starts to build up on the nut, it becomes very difficult to remove the nut. I wanted to install a steel front skid plate, but have been fighting this nut for awhile now. Below is the solution I came up with.

Photo of the broken welds on the nut (passenger side only).

I could get my fingers in the cross member, but rust prevented me from loosening the nut by hand. A socket wrench with angle adapter was the only way I could get a socket over the nut, however the awkward size/shape of the nut caused the 9/16 socket to keep slipping (13mm & 14mm don't fit on the nut).
I ended up spraying the nut using magnetic penetrating lubricant and let it sit overnight. Tried the socket again and was able to get it loose, then removed it by hand.

Rather than reinstall the weld nut, or swap it out for a flange nut, I needed something that would allow me to tighten the bolt without needing a wrench on the other side. I cut some 3/8" metal into 5" long sections, and then tapped treads into them. The idea is that the metal would rotate against the inside wall of the cross member and self tighten from there. When needing to loosen and remove the bolt, this metal bar would hit the opposite side wall of the cross member and hold itself while undoing the bolt.

Install of this new hardware went really well. There are enough threads in this metal to get a good torque on the bolt. The hardware is skinny enough to be able to maneuver around inside the cross member while still having enough room on either side for your fingers.

I am unsure of what to do with the driver side, as it is not broken yet. I figure it will break eventually, and it might be better to break it on purpose and remove before rust builds up on the nut. I made two of these tapped metal bars, so that I could move ahead replacing the driver side when ready.

Here is a photo of the non-broken weld nut on the driver side.

 

Nice! I might have missed it, but did you go with a larger diameter bolt? That would be something handy also.

 

@GarlicFarts, is this the same as yours?

 

I kept the same bolt. I could possibly go one size larger, but any more than that and I would have to modify the RCI transmission skid/engine skid holes, and possibly enlarge the hole on the cross member. Upgrading the bolt didn't seem necessary since the engine skid bolts on with 6 bolts.

 

Good stuff. It was more about just using a single 17mm to drop it.

I do take mine off for oil changes having cleaned up messes from other skids that had oil change access. Just works better for me with it gone.

 

Put anti-seize on all those bolts. Also put a little on the 4 countersunk allen bolts that hold the oil filter access panel in place.

 

Next time just use a SS Rivnut.

 

I think so, yes.

Honestly not the worst idea. My issue right now as Mr. Floats knows is the damn thing ain't coming out. So, that's good to see someone else and how they approached it. I'm good with just a SS flange nut though.

 

Thank you for this thread, glad to know I am not the only one that did this! Also seemed weird no socket seemed to work on that top nut.

 

Oh an update.

Tried to reach up in there with a wrench of some sort. We might have had some success? But we ended up just needing to sawzall the bolt off. Got all over 5 bolts out, let the skid hang down a bit, and got a sawzall blade between the skid and cross memeber, and cut it out.

Replaced with rivnut.

 

An 8 point socket should fit the square nut.

 

Cutting it was my plan after some time fighting with it.

 

I think it is an odd size as well.

 

I've been faced with situations like this a few times myself. What I've found works best is to weld a hex nut to the piece of metal. My experience has been that threads tapped into mild steel tend to strip out easier than if using a nut.
Additionally, if you drill a couple holes to either side of where the bolt goes through the frame or crossmember, you can then weld the metal piece w/nut into place by welding through the drilled holes (plug-welding it) so it's not moving around in there every time you disassemble it.

 

Get a riv-nut gun from Harbor Freight. My wife’s 4-runner skid plate had about 8 stripped nuts and the dealer quoted $600 to fix. Harbor Freight for the win!

 

Thank you for posting this. After trying to get a wrench on that nut for an hour I finally looked it up to see wtf was going on. Stupid design!

Cut it off and replaced it with an M8 rivnut (did have to drill out the hole just a little). The rivnut works for me but it’s maybe not ideal because the cross member is slightly curved there, so it sits at a slight angle. My skid pan has plenty of room in the slot to accommodate that though so it’s just fine. And you’d better believe that now I have anti seize on all the bolts too.

 

When my weld nuts broke loose I just ended up cutting the hardware off because they were rusted and seized up on me. The easiest solution I came up with was using a spare nut I had and holding it in place through the side opening of the crossmember and tightening everything down with a flex head ratchet. That was about 6 months ago and everything has held up so far.

 

Yeah, the idea of fucking around with that every time I needed to drop the pan sounded annoying, so I went with the Rivnut option.

 

+1 I drop my skid every year for undercoating. So it's not really one I can set it and forget it.

But if you can get a wrench in there relatively easily, it's not that bad. Magnets on a stick would help a lot too.

 

I've been wondering if rivnuts are strong enough long-term? Obviously the skid plate isn't going to fall out, but will have the same problem in a few years? If the old nut failed due to corrosion/over-tightening, aren't rivnuts a lot weaker? Do you just keep the hardware coated in anti seize?