Help ? Rusty fire hydrant disassembly

[Indyducati]

Hi folks,

I bought an old fire hydrant for my dog. A US Pipe Sentinel 250.
I'm trying to disassemble it completely, before striping and repainting.
The top... bonnet ? won't come off. I know, I know, I know, I should just leave it stuck and start painting...

The bonnet is 10" in diameter and smooth. It's got one hole, about .655".
The manufacturer shows disassembly with a spanner wrench in their documentation.

It seems the body or barrel has four tabs sticking out at the top, like a pill bottle.
The bonnet has four channels that grip the tabs on the barrel.

I've been soaking in penetrating oil for a month. I regularly pound on it with my BFH and punch. No movement yet.

What's my cheap, next, step ? I can imagine fabricating a big chain wrench or spanner.
Could I thermally shock it with a charcoal fire and a bucket of ice ?

Any ideas ?
Thanks,
Steve

 

[southalabama]

No help but will be watching. Just sandblasted and painted mine without complete disassembly

 

[dffay]

Consider a big plastic garbage drum and immerse the entire thing in Muriatic acid water. Let it cook for a few days.

 

[driftpin]

Just wondering about your motivation for disassembly. What would that accomplish over leaving it alone? I have a Corey hydrant that is stripped but not painted. I am a retired FF/paramedic. We had to use a 'Corey adapter' because of the predominant threads on the steamer caps (the big one) on the city hydrants. A Corey hydrant would get the adapter then the soft suction hose would attach to the adapter, and the other end of course would go to the pumper inlet.

Heat is usually my method for breaking the grip of rust. I'd use my gas axe and get each section incandescent, and quench it with PB Blaster or ATF/acetone, though the latter might flash-ignite, so wear a full-face safety shield, suitable gloves, and other protective clothing. It could even shatter so wear enough suitable protection.

 

[The Cobbler]

after fighting I would be inclined to leave it as is. but, you could try heating the bonnet hot and not putting heat on the hydrant . (some will creep there) and then try to spin it. a made up spanner wrench would help alot too, I think .
maybe even a short pc of round bar fitting snugly into the hole for something to hit on with a hammer .
my luck would be I would beat on it until I broke it,then wish I had not tried to separate it

 

[Indyducati]

Just wondering about your motivation for disassembly. What would that accomplish over leaving it alone?

Driftpin, it would just bug me, if I didn't at least try a few times to break it free.

I figure I've still got a $50 budget and a couple hours of sweat I'm willing to invest.

I appreciate your suggestions!
Steve

 

[BigMike782]

I would try rattling it with a muffler gun. Don't get crazy but enough vibration to work it loose.
I have had great success doing this.

 

[2oolhound]

Sounds like it must have got wet from inside somehow. Your best bet to crack it loose would be dog urine.
Sorry can't really help but nice score! should look good painted up.

 

[snyder]

Chain wrench?

 

[fitter30]

B ack 80 - 120 years they screwed large pipe 8" - 12" they tighten them with chain wrench. Heat is your friend full size torch big rosebud tip. The gas would blow ur budget!