That final bolt

It always seems that the last bolt is always the one that you can never get off cleanly, and this time I am stumped.

I am changing the original rear shocks on my (admittedly ancient) 1995 Tahoe, and the upper bolts are secured by U-Clips. These are pieces of sheet metal that wrap around the edge of the frame and are threaded to retain the bolt. The problem is that the final one has sheared, and so now its just a piece of metal rusted to the top of the bolt, and spins freely.

There is enough clearance to squeeze a needle-nose locking pliers into the space above the frame, but the pliers aren’t strong enough to hold against the torque necessary to move the bolt. I tried gripping the edges vertically and horizontally and it is just too much.

I tried penetrating oil (WD-40), without much luck. I have tried breaking it free with a torch, but there is not enough metal and not quite the right angle to make them expand at different rates. I tried flexing the tab in hopes of inducing metal fatigue and breaking it off; it turns out my muscles fatigue a lot faster. I even experimented with drilling out the bolt from underneath, but the bolt appears to be super-hardened and my drill bits barely made a nick.

What’s the method here to remove this freely-spinning inaccessible threaded metal plate?

The clip in question, started out looking something like one of these:

WD-40 is NOT penetrating oil. WD stands for Water Displacement. And that’s what it does best.

Try PB blaster or Liquid Wrench…you’ll get much better results.

Cut the bolt with a torch or cold chisel…

I think at one point I knew that WD-40 isn’t penetrating oil. Will try your suggestion.

Since I am working under the truck on a creeper, I am not comfortable going at it with a torch from there, and can’t get to it with a torch from above. I’ll try the cold chisel, but don’t have much clearance to swing a hammer.

Thanks for the suggestions

Drill it out??

Are you talking about a nut plate? If so, you might try a new pair of vice grips. If you use an older pair, and the teeth are not very sharp, they will have to be squeezing too hard to get a grip, and the harder they squeeze, the tighter they will squeeze down onto the bolt, so a new pair with sharp teeth that will “bite” into the metal part just might do the trick. I broke down after using the same pair of my favorite vice grips for 20 years, and got some with sharp teeth, for that very reason. Worked like a charm.

yes, a nut plate along the lines of what you have shown here. the bottom of the plate is gone and the top is short and rounded, above a small flat area.

So, I got a brand-spanking new vice grips and it actually hold worse than the ones I am using now. I can’t use full-size grips because of the limited space, so I got a smaller one, but it slips just like the other.

A sawz-all would work, but I don’t have one and there is no way to approach the bolt anyway. I am thinking of slicing it off with a dremel tool, using a carbide bit for hardened steel. I have to wait for the battery to charge before giving it a go.

This job is going to take me 30 minutes, plus 2 days and several trips to the tool store to remove a single bolt. Ah well…

That’s a good thought. I tried that above. The bolt appears to be hardened steel (grade 5 or 8 or maybe grade 42). My steel bits are hardly dimpling it.

These are called J-nuts. One way to remove a broken J-nut when access is tight is drill a small hole thru the panel/plate it’s mounted to and thru what’s left of the J-nut. Run a sheet metal screw into panel and J-nut. Now the fastener can be removed without the J-nut spinning.


Cool idea! There might be enough of a flange left on top to make it work. I’ll give it a try.

WD-40 absolutely is a penetrating oil. The trick is to be patient and let it sit for a while, maybe even overnight for it to work.

On the really stuck nuts, I reach for the Sawzall and a pack of metal blades.

An air die grinder usually works. Then there are Dremel tools or their clones. You are working way too hard.

Well, WD-40 and PB Blaster both failed in this case. I am guessing that the bolt resembles a rusted rivet at this point, but it’s hard to get eyes on the back side of it.

I bought a sawzall, because I’ve always wanted one, but there is no way to clearance around this bolt. So I am going to try the dremel with a carbide cutting bit this morning. This is a bit dodgy, because the bolt is hardened and I am working pretty close to it on a creeper.

I know your pain well. I have battled many of these restoring Corvettes. When they break, you know you’re in for a battle. They are used where conventional fasteners won’t work so by design, they are a bear to access when they break loose.

My final solution involved bending a wrench to hold the nut. I had quite a few flat wrenches, like the kind you get in a motorcycle repair kit. I suppose any wrench that fit into the available area would work.

I heated the correct sized one up and bent it 90deg so it would lay flat against the frame and hold the nut. I clamped the wrench against the frame to hold it secure and after some liberal soaking in B’Laster PB, buzzed the bolt out. It’s another option for you to consider.

Doh, I didn’t read the whole post. Lazy.

WD-40 absolutely is a penetrating oil

People use it as a penetrating oil…but it wasn’t DESIGNED with that purpose in mind.

WD-40 was and IS designed to remove moisture…It does a LOUSY job are penetrating…

Liquid Wrench does a MUCH better job…You just have to let it do it’s work…It will take a good 12-24 hours to penetrate.

I want to thank everybody for their ideas and suggestions.

As I wrote above, this is a 1995 Tahoe, and it needed about $5-6K worth of repairs, as estimated by the dealer. New rear brakes (brake lines, drums, etc), rear shocks, master cylinder, oil pan, differential gasket, a variety of front and rear seals and a few other things.

We only use it occasionally (<1K miles per year for the last 4 years), so I decided to do most of the work myself instead of buying a new car that would mostly sit, or spending more than the truck was worth.

For less than $700 in parts, I got everything else done, and of course the shocks were the last thing, and this was the last bolt. Of course.

I am pretty well equipped, but I am still working in my driveway on the jacked-up truck, with the bolts over my head. I finally got down to using the dremel tool, and when I saw the light cloud of metal dust floating around my head, I decided it was time to call it quits. This bolt requires that the truck be up on a lift and someone with a better torch than I have.

Again, thanks all for your help and encouragement.