I gently wire brushed the outside threads and material, grooves, etc. I plugged the holes and let it sit in pb blaster, soaked it in muriatic acid for maybe 15-20 minutes (didn't want to damage the brass), then let the whole thing soak in penetrating oil overnight for about 12 hours. The petcock on the bottom is freed up now and I can turn it open and closed. I still can't really get the shutoff on the bulb to move though. It's stuck in the open position. any tips on how to get it to unfreeze and work, get it clean, and will it be safe or too likely to clog my line?
The shutoff valve is tapered, you need to remove the cotter pin, any washers and the spring. Then the valve is ready to come out. Whether it wants to or not is another question.
That type of valve is called a plug valve.
The shutoff on these is a taper fit in the housing. Usually there is a cotter pin, washer and a spring on the stem of it (or some other fastening system). if you remove all this, then you can consider a couple of options. I see you own a '25, so I assume you are working on the version that mounts under the seat, but I don't think it really matters.
1. HEAT. Brass expands much more quickly than cast iron. If you apply some quick HOT heat to the stem of the brass valve plug (only for a few minutes but hopefully get it red) AND THEN WALK AWAY!! Brass is very brittle and weak when hot, so don't try anything until it cools. As it cools, my favorite penetrating lube for this is ordinary candle wax. Apply the wax somewhat liberally at the temperature of the object where it is still smoking a bit, but only just. Now leave it a bit longer until you handle it. With a bit of luck it will now move and you can remove the valve stem and finish cleaning things
2. Another option is to make a custom punch that fits closely the end of the stem and applies force to as large a area as possible. A sharp tap with a hammer might work.
3. A combination of above.
Heat is really useful for disassembling things without breaking stuff and candle wax has really worked well for me during this process. It "wicks" in beautifully to threads if applied when the object is still hot and just barely at the "smoking temp"!!
Once you have it all apart and cleaned up, to get the valve to now work and seal against gasoline, I like SOAP! The scum from the bottom of the soap dish works well, is gasoline proof and lubricates well. I am not sure if ethanol might not affect it, but I try to avoid ethanol gas in my old cars
Thanks for the responses guys. I also found an old mtfca sheet suggesting putting it in a freezer, as this will cuase the brass to shrink. then it was much as you guys suggested: remove the washer and pin, then tap out carefully. Then undo the screen by taking the big square nut off. Off to give it a shot now.
As Les posted, use heat, a propane torch is ok if you don't have acyl/oxg rig.
Heat the brass and then put it in the freezer to rapidly shrink. Then before any pressure use penetrating oil (haven't tried the candle trick)
Carefully punch the stem end out, twisting the handle too hard can bend or break it off!
Do the same to the large brass nut, heat and freeze, then turn it off to inspect the screen on the backside of the nut. Often the screen is clogged or busted, replace the screen by soldering in a new screen. use a new lead washer seal too.
For a non-weeping valve, using some lapping compound on the taper to seat better in the iron bulb works well.
Only by taking the whole bulb apart can you properly restore its function.
As instructed I heated and rapidly cooled it. It worked! I got both the shut off and the disk section off. Cleaned out the insides with soapy water and an old tooth brush, rinsed it well. Now I just have to order a new screen, gasket, and pin from Lang's (I'm assuming they sell them). I have to order some parts from them anyway. Thanks for the help guys.