Rusted fasteners sometimes just can't be successfully removed

I had this unique opportunity presented to me, so decided to give it a go. Do the experiment. In case anyone’s interested in the result, posting here.

What happened is I dug up a short section of 50 year old 1/2 inch galvanized iron pipe a couple of weeks ago. From an ancient lawn sprinkling system. You know it was ancient b/c practically nobody uses iron pipe for the low pressure part of lawn sprinkling systems these days. Anyway the pipe section had a fitting where a sprinkler head could have been placed. Instead it had a 1/2 inch iron plug screwed in. You know, those square shaped iron plugs. Everything is totally, unbelievably rusted. My goal: See if I could remove that plug!! This was done under ideal circumstances; I could do everything on the work bench. The question: If I applied everything I’ve learned here at Car Talk, would I be successful?

I wire brushed the area until most of the external rust was removed. Then soaked the threads w/rust-dissolving penetrant daily, for 7 days in a row. Wouldn’t budge. Tried clockwise, counterclockwise, wouldn’t budge. Next I heated it with a propane torch to the point it was glowing. Wouldn’t budge. Heated it again, pounded with a hammer. Wouldn’t budge. Next I heated it until it was glowing, then applied candle wax. Wouldn’t budge. Pipe wrench, Crescent wrench, whacked the wrench with a hammer to shock it loose. Wouldn’t budge. Heated it up to glowing again, then poured cold water. Wouldn’t budge. Tried more leverage, used a pipe over the handle of the Crescent wrench. This time something budged at least. The 1/2 inch plug head sheared off. … lol…

My conclusion is this problem I took on for scientific purposes either was completely unsolvable, or it required tooling I didn’t possess, such as a major heavy duty impact wrench and an impact socket designed for a 4 sided bolt head. Any other ideas/conclusions?


Shaking it loose with an air wrench is about the last resort.

We had a Subaru in once with a trashed 4WD transmission. It was less than 2 years old, had almost a 100k miles on it, and every single mile had been out in the oil field muck and mud along with being axle deep in various chemicals.

I spent 2 hours AFTER allowing everything to soak overnight with PB Blaster to no avail. Torch, air chisel , nothing worked. Finally I put the cutting head on the torch and pretty much annihilated everything holding that transmission in place.


We live this experiment around here:grinning: I found a 1/2" SK ratchet in the bottom of a metal scrap barrel in the fall that had been sitting with a foot of water in it for years.

I locked the square drive part in my vise and gave it some penetrating oil. A couple of times a week I gave it some more oil and put a pipe over the handle to try to work it. just before spring came I got a little movement finally got the snap ring out and cleaned everything up with a rotary wire brush and oiled it… Works like new and I use it before my Craftsman.

I also have a 1972 eight hp Airens snowblower that I bought in 1990. I have uses it every year since but the augers are rusted to the shaft and were that way when I got it. It has defied every effort to free it.

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When I have something small enough like your ratchet I put in a container of ATF & keep trying to loosen over a period of time when I moved to the house I live in now the first time I dug up ground for a garden I found a pair of pliers that looked to have been under ground for who know’s how many year’s soaked in a can of ATF took 2 month’s worked with them once a week before they broke loose wire brushed them & they worked good that was 12 year’s ago & still use them to this day.

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I dunno. I think some stuff you just end up breaking. I had to get (absolutely had to) the aerator off of the sink faucet in the bathroom in order to mount an attachment. Wouldn’t come off. Ended up twisting the fitting off of the copper pipe inside the faucet. Went to the other faucet and did the same thing, so now I had two faucets with the end ripped off. I had another faucet from a remodel so went to do a temporary change and the shut off valve wouldn’t close completely. Sheesh. Dinked around for over an hour hooking something up to work. Then I had to take both the other faucets apart and re-braze the ends back on, then re-install. I used anti-sieze on the new aerators. Water pipes are bad news. Gotta have extra time, tools, and materials anytime you mess with them.

You are dealing with a pipe plug with tapered threads. This puts a compressive stress on the plug and a tensile stress on the pipe fitting. Makes it MUCH harder to remove than just plain 'ol bolts.

I’d suggest the trick in this case, other than far more penetrating oil/days, would have been to drill out the plug. Start small and get larger and larger while maintaining the square so you can turn it. I’d apply heat, too, from an oxy-acetylene torch - gets much hotter, quicker. Left handed drills bits can help this, too, as the drilling forces can spin out the plug. Drilling the hole relieves the compressive stresses which makes your removal progressively easier. Maybe not easy enough but in the end, you may end up drilling nearly out to the smallest thread and using an easy-out.

And you still might not get it out!

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And don’t forget impact wrenches are much more effective on rusty nuts and bolts than simple ratchets.

I’ve seen Bee’s wax work better than candle wax.

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That reminds me of an upstream oxygen sensor that was mounted on my '98 Civic’s exhaust manifold/catalytic converter. It was totally fused, no way to get it out. If I remember correctly, the replacement OEM oxygen sensor was $180 at the dealership.

Like your scenario, I think the threads had fused into a solid piece of metal for all practical purposes.

You know what’s crazy? That catalytic converter cost me at least $600, including labor. Based on a quick search, I can get a brand new catalytic converter on Amazon for about $100, and oxygen sensors for about $30 a piece. I guess parts prices really decline when your car gets this old. I might just go ahead and replace that catalytic converter to get rid of that CEL I’ve been staring at for the past 17 years or so.

50/50 mix of acetone and ATF is a nasty substance, but it’s worked pretty well for me for getting badly rusted stuff off. Drip it in, let it sit for awhile, drip more in, repeat, repeat, then torch it and right after it’s torched, air wrench to vibrate the rust loose.

Of course, that’s a long, time consuming process and it’s faster just to drill the stupid bolt out and put a new bolt in, so that’s what I end up doing more often than not.

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I have yet to encounter a fastener that, when reddish-orange, did not come out. They often screech and complain but they come out :wink: