Best method to loosen and remove stuck brass nut?

Greetings, All,

I have been working on the wonderful old stove, part of an early Formaldehyde Generator, and am having one heck of a time getting the large brass nut removed from the end of the pump tube. I've tried heating and quenching, and quite a few different penetrating oils, including PB Blaster, and Break Free, and so far, the big nut shows no signs of loosening. Here are some photos of the nut in question:





And one which not only shows the nut setup, but also, for my good Mate @nmp , the pump bucket end, and fixtures of the pump rod, as he's been dealing with a setup just like this.



If you Gentlemen have any suggestions, or recommendations for loosening the brass nut, without damaging either the nut, the brass tube onto which it is screwed, or the stove font, I'm all ears, and would appreciate your help!! I'm really looking forward to restoring this Old Timer, and getting it back to it's original medical setup, and use, as a Formaldehyde Generator!!! Thanks, Gents, and God Bless!

Every Good Wish,
Doc

 

Doc, I can well understand your problem.
How to remove the nut without distorting the tank?
You seem to have done everything that I would have done.
All I can suggest is that the the nut needs a sharp shock to make it break free.
But that is easier said than done.

 

In your second photo it almost looks like a bead of solder between the nut and threads.

 

Hi Doc, do you really need to shift this nut? As you know the tank is made from relatively thin sheet, and will distort and buckle if overstressed.
Differential expansion is worth trying again, with crushed ice in the pump tube and then boiling water introduced into the tank. If you can get some penetrating oil into any gap which appears, you may then be able to loosen the nut, and remove the tube.
Good Luck,
Best Regards,
George.

 

I think Heirphoto is right. Looks like its soldered on

 

- yes the nut itself is permanently fixed to the pump tube threads - the nut itself should not come loose from the tube, Doc's problem is trying to unscrew the entire pump tube assembly whole, as shown in this photo:



(https://classiccampstoves.com/threads/1892-96-primus.18170/)

 

@Doc Mark , I will add time to this equation.
Penetrating oil, #1 acetone and ATF 50/50, #2 Kroil, or any other, in that order.
Warm it up, add the oil to the threads, and come back the next day, and the next and the next.
The warmth will add to the chemical reaction and time will penetrate. I would say weeks may not be out of the ordinary.

Ken in NC

 

totally agree with Ken, 50/50 ATF/Acetone is the best I have ever used
Jan

 

Good Evening, @shagratork @Heirphoto @kerophile @gremlin70,@igh371 @snwcmpr @scouterjan , and All,

To use an old Texas expression, "WELL, shut my mouth, wide open"!!!

Gentlemen, you have figured out my conundrum!!! I had always thought that the nut on this type of system, had to be remove, and then the inner pump tube could be lifted out. Well, thanks to some astute observations on your part(s), I now realized that the nut is there to allow the pump tube to be unscrewed, completely, from the soldered fixture on the tank!!! WELL DONE, MATES!!!

So, now that I have a MUCH better idea on how this system actually works, I can better focus my energies in the proper place, and thereby, finally be able to remove the pump tube on this Old Timer, and service it!! A very special thanks to our new member, @Heirphoto , and my long-time and very good friend, @Christer Carlsson , too! Heirphoto, you may be new, but you're spotting problems just like an old, and very experienced CCS member!!! Well done! And, thanks to the post from Christer, that Ian shared, (Thanks, Ian!!!), I have learned a very valuable, and very necessary lesson!!! Well done, all around, Friends, Neighbors, and all you Little Shavers, out there on CCS!!!! I now know that this problem will eventually be fettled, and I owe that success, when it finally comes, to all of you Gentlemen!! HUZZAH!!!! Take care, and God Bless!

Every Good Wish,
Doc (who is a very Happy Chappy tonight, thanks to you all!!)

P.S. This sort of teamwork and help is one of the reasons I LOVE CCS!!!! Thanks, again, Guys!!

 

Hi doc here in the Uk we have an aerosol spray that plumbers use to freeze pipes to allow them to cut water pipes with out draining the system,you could fill the tank with boiling water and spray the pump tube end to cool it fast ths may loosen the joint, sometimes trying to tighten then loosen works as well?!
Good luck
Nick

 

Doc, that looks like an interesting old stove! Is it an old US Primus?
We will see more of it, I hope.

( @Doc Mark )

 

@nmp @Christer Carlsson ,

Good Morning, Nick and Christer,

Thanks, Nick, for that excellent suggestion. I'll check out local Plumber's supply places and see if I can locate some of that stuff. In the meantime, I'm continue to soak (this time the proper side!) the brass nut, in hopes that, with proper substances and a bit of work, the nut will finally release it's death grip, and allow fettling the NRV on this Old Timer!

Christer, yep, I will most definitely be posting more of this old stove, and of two others, one is a US Made Primus, which we discussed in another thread, and the other is the original stove for my Novy Formaldehyde Generator, medical device. You may recall that that stove, too, had a nut which would not release, and after much work (though I now realize that I applied the penetrating oils to the wrong side of the nut!), in desperation, I unsoldered two parts on that old stove, and realized that the brass keeper tube is supposed to remain on the tank!! YIKES!! So, now I have to not only resolder that tube, but also the bottom plate, which I removed at a past CASG event. Oh, well....... best laid plans, and all.....

Here is a quick "group photo" of the three Oldsters in question, including the stove seen in this thread, which is in the middle stove in the photo:



And, here's my Novy, which was designed to "sterilize" hospital rooms in which very contagious patients had been treated. It was an excellent medical advancement, though not totally effective.



So, more to come, and more than one stove in need of fettling in this way! Thanks, so very much, to you for posting the excellent thread about your own Old Timer, and because of you, I think my own fettle can finally be completed successfully!! Thanks, to @igh371 , too, for sharing the link that led to this great information!! Well done, Mates, all around, and VERY much appreciated!! Take care, and God Bless!

Every Good Wish,
Mark

 

Thanks Doc!
I'm looking forward to see more. It looks like you have some fettling to do on those.
I wonder about that strange air release screw. It's on both stoves with the removable pump.

 

for stubborn bolts, I generally use an impact wrench, of the type used to remove tire bolts in tire shop, compressed air operated ones are the best, and you can regulate the impact force.
Try starting with light impact force.
Some electric drills have an "impact drive " function too.

 

Soak the whole thing in ATF and heat it to 90C for an hour or two. Use a sousvide heater or heating element with circulator (a stainless steel type). I have also had great success with hot water and kitchen soap in a ultrasonic parts washer. Make sure you use a soap that does not harm brass/copper.

 

Btw most old brass stuff was hardsoldered. Meaning you can heat it to about 400 C without damaging it. Then use a cooling rust desolver spray. You should be able to get this from you local hardware store. This kind of rust desolver cools down to -40 C or more. You can also use a compressed air can for electronics cleaning. This will turn very cold if you do not shake the can.

 

And a last tip. When you put it back together use copper paste (the suff you put on brakepads on cars) on the threads, and it will never be stuck again. Just put a small amount on all threads.

 

Doc, Glad I was of help. While new to stoves I have been restoring old farm engines, motorcycles and mainly old Land Rovers for 30 years so get good at figuring things out.

 

I once took a two week long (10 day) blacksmithing course. Old fashioned style using coal forge etc. One of the things the old guy taught the 5 of us taking the course was how to use heat to remove sticking nuts and bolts. He told us the secret is in the expansion of the metal. You want to expand the metal of the nut, and shrink the metal of the bolt. It's a physics thing.

You only should be using heat to expand the nut, not the bolt. That takes some thinking but ice or the aforementioned plumbers freeze (freon gas) to cool the bolt (in this case the pump tube) and heat to warm the nut (in this case the fount metal) will cause the right part to expand, the other side to contract. You've got to be fast because in brass the conductivity is very good.

Whew, I think I got that right????? Let me know if I didn't not reverse my thinking in mid stream will You?
Stan