I'll chime in with my method,
With the top tube and upper pull rod removed, unscrew the lower pull rod with a socket wrench and after a few turns the pedal should drop.
You may find that the coupling nut that attaches the lower and upper pull rods together comes off of the threads as you unscrew it, leaving the lower pull rod intact with just bare threading on top. This has happened to me multiple times. It's an easy fix, though. Just coat the threads on the top of the lower pull rod with JB Weld, than screw the coupling nut back on all the way. Leave it be for 24 hours. Then you can proceed with unscrewing the coupling nut, which will dislodge the pedal.
Hold the stand upside down and pull out the lower pull rod (so the spring comes with it. If you leave it upright, the spring has a tendency to stay inside the tripod tube). Take off the spring, wash it in soap and water and then let it soak overnight in paint thinner or mineral spirits in a small bottle, like a Snapple bottle or Salad Dressing Container. CAUTION: Paint Thinner stinks, so do this outside if you can. There should also be a small, asterisk shaped washer that slides onto the lower part of the lower pull rod, but stops at the small "wings" built into the rod that also stop the spring. Make sure the washer is in good condition and let that soak overnight too. If the washer is damaged or missing, you can find a replacement at your local hardware store. Just be sure to take the lower pull rod with you so you can verify that the new washer fits on the rod but is small enough to stopped by the "wings".
It's also a good idea to clean out the lower tube (the tripod). The gunk build up in there is pretty gnarly. Here's how I do it. I recommend doing this OUTSIDE in fresh air!
Put some painters tape or duct tape over the hole at the bottom of the tripod (where the lower pull rod comes out and attaches to the pedal). Take a funnel and pour paint thinner into the lower tube until it's full. Then take a bottle brush (narrow, long brush) and scrub the inside thoroughly. You will have a little liquid leaking out the bottom, that's ok. Turn the tripod upside down to pour the (now disgustingly dirty) paint thinner out. Repeat this process several times, until the paint thinner is clear after scrubbing/soaking. You'll be absolutely amazed at how dirty the inside of that tripod base was!
ANOTHER WORD OF CAUTION: Do this over pavement, dirt or weeds/plants that you don't care about. The paint thinner WILL kill any grass or plants it comes into contact with, just like gasoline. Also, like gasoline, it can leave a residue on pavement, so be conscious of that. Then, remove the tape covering the bottom hole and put the bottle brush up there and scrub a few times. Finally, pour some more paint thinner down the tube, just to let it all flush out thoroughly. Let the tube sit for awhile so that everything evaporates (again, OUTSIDE if you can). While the spring is soaking and the tripod is drying out, you can clean /polish everything else.
To clean the lower pull rod, use soap and water and then lighter fluid or a little paint thinner to get all the gunk and residue off. The next day when the spring has soaked itself clean, wash the spring with soap and water and get your washer and spring in proper position on the pull rod (AGAIN: Dump the used paint thinner OUTSIDE on dirt or weeds). It's time to lubricate and reassemble! An optional step before reassembly is to use a small rubber grommet that goes in between the top "yoke" on the pedal (with the threads that the lower pull rod screws into) and the hole that you had previously covered with painters tape while cleaning. This is optional, but it creates a soft impact and no noise when you take your foot off the pedal. Some people use small cymbal felts. That's ok too, but I prefer the rubber grommets. Way more durable and way thinner than a cymbal felt, so the angle of the pedal isn't affected by having something too thick, preventing the pedal from "going up" all the way. You can get one for about 30 cents at the hardware store.
Use whatever lubrication you like (I prefer Tri-Flow with Teflon). On a piece of cardboard or something disposable, assemble the washer and spring to their proper position, then lay the lower pull rod down and spray it thoroughly with your lubrication of choice. Insert the lower pull rod horizontally into the tripod base by holding the tripod base horizontally, so that you can put the lower pull rod into the tripod base without the spring slipping off. Then, screw the lower pull rod into the pedal (tight, with your socket wrench to prevent it from unscrewing there when trying to unscrew the upper pull rod!), insert the upper tube and upper pull rod and work that lubrication in! You'll have to keep wiping off the excess as it drips down near the threaded "yoke" where the optional rubber grommet is, but that means it's working. Don't forget to put some lubrication on either side of the heel plate too.
Good luck and your hi-hat should have much more "spring in its step" after this. That is my all-time favorite hi-hat stand. I've got about 15 of them and I love them! (EDIT: I just counted and I "only" have 13!")
