Installing a Vintage K Valve on a Steel 72

[Akimbo]

I've heard of that but have never seen it, they must think that people that buy Acuras just call tow trucks when they have a flat!

I had the option to get an undersized fake spare or run-flat tires when I ordered a vehicle in 2019. The salesman convinced me to go with the run-flats saying the ride was just as good.

1. I now doubt that is true. They run flat because the side walls are super stiff.
2. He did not say I would be lucky to get 20K miles/32K kilometers out of them. I get 60-80K miles on my other vehicles.
3. Or that are much more expensive to replace.
4. And that there are a lot fewer manufacturers to choose from.

Of course I had to replace them during the deepest part of last year's supply chain debacle.

On the other hand, there is about a 60 miles of mountain road that we frequently travel to get out of the boonies and a good part has no safe place to pull over or even pass.

 

[Eric Sedletzky]

Several years ago, I was forced to remove my J valve on my trusty US Divers steel 72 tank. The reason for the removal was the LDS refusal to fill tanks with J valves. “Safety” was their official rationale. So, I bought a used XS valve from them and got my tank filled.

The XS valve has served me well and i would recommend them to anyone. But unfortunately, I have several vintage short yoke regulators that have trouble fitting on this modern valve. So, I found an era correct US Divers K valve that will better serve my ancient regulators. I found a rebuild kit from Silent Explorers and installed it in the USD valve. Super easy, works and looks like new.

Now the hard part. The XS valve is on tight and won’t budge, even with a 1-1/2 wrench and a three pound hammer. The problem for me is keeping the tank from moving. I don’t have access to a tank vise, so it looks like I’m out of luck and dependent on the LDS. But no, I remember a trick I was taught by an old salt many years ago. So, I jack up my truck and put the tank under the wheel as I drop the jack down. Now the tank is immobile with 5000lb of Ford’s finest on top of it. Even with the wrench and hammer the valve is stubborn, but finally breaks free. On goes the USD valve and all is well. Anyone have other ways to change out valves?

Question:
Is this a 1/2” tapered pipe thread or a 3/4” straight thread with O-ring valve?
If it’s a 3/4” straight thread then there’s absolutely no reason for it to be hammered on that tight. I had a hydro facility do that once to one of my tanks and I was furious! It was a new guy working there that didn’t know.
Anyway, 3/4” valves only need to be tightened just past hand tight to bottom out. The O-ring does the rest.
1/2” tapered valves take a 160 ft lb torque. I wrap six wraps of teflon tape around the valve then install. I lay them on the floor on a carpet and pin them down in between my knees and that usually works to get enough grip. You can also wrap a strap around them to stop them from spinning. Use one arm to hold the strap and the other to work the wrench. You’ll need a short open end wrench the size of the valve with a 3/8” or 1/2” square hole (crow foot wrench) to be able to use a torque wrench.
Once any tank is pressurized either style valve isn’t going anywhere.