G250 stuck adjustment knob

[PfcAJ]

Hey yall,

I've recently acquired a sweet g250 in beautiful shape. The only hiccup is that the adjustment knob is stuck. It looks to be all the way out, and it will not budge. I soaked it overnight in 50/50 vinegar and water per a compadre's recommendation, but its still locked up.

Any suggestions?

 

[redacted]

Hot and cold and more soaking. I don't have a G250 but I'm pretty sure you can remove the barrel and knob which will make it much more effective. Soak the whole "user" end in ice water and then run HOT water over the barrel as you try to work the knob. The hot water will cause the barrel to expand while the knob stays somewhat cold breaking the deposits and allowing water to get in and dissolve them. It will probably take a few treatment cycles but as long as you are patient, you should end up with a good regulator (even if is is plastic).

 

[cbrich]

I would try an ultra sonic cleaner to break up the corrosion in the threads.

 

[=C=]

When was its last service?

 

[redacted]

When was its last service?

How would that matter? A poor service job coupled with inadequate user maintenance could produce that problem in short order (weeks).

 

[PfcAJ]

Thanks. I don't know when the last service was, nevuary 32 for all I know

ill try the hot cold thing and see if that frees it up. Thanks for the advice!

 

[rsingler]

The best recommendation was the ultrasonic. The problem is crusting and crystallization of the brass oxides (various). Hot and cold may help, and soaking certainly would IF the vinegar could get to all the crap, but it may not.
If you don't have access to an ultrasonic, get a brad hammer or a child's play hammer. Holding the reg in your hand, tap on the adjustment knob with a sharp rap. You'll have to gauge what won't mar the knob. Because the G250 is plastic, don't strike the knob against a hard surface.
This poor man's ultrasonic may shatter enough of the crystals to allow movement. Once you get ANY movement at all, back in the vinegar and work the part a little then let it soak.

The first time I was shown this (to unfreeze an IP adjustment hex screw on a green diaphragm 1st stage) I was amazed.

 

[Zung]

+3 for the hot/cold/soak/ultra sonic.
Last time I looked, Harbour Freight still has a us cleaner for 30 bucks.
Of the dozen plus G250/156 I have, none has resisted the treatment.
After you've done with it, lube the thread COPIOUSLY, like you would with peanut butter, only more. I use the regular Dow 111 silicone grease that's plenty good enough for this application, which is to prevent metal to metal contact.

Edit: a silly question: did you remove the D clip?

 

[OkByMe]

White mineral deposits on threads, pinch points and other hardware is easily removed with CLR. I suspect in this case that the salt or mineral deposit on the internal thread is the culprit, you might try soaking barrel assembly in a rich solution of CLR. I use that instead of Vinegar since it will remove just about anything without a lot of discoloration.

 

[rsingler]

I don't have a G250...you should end up with a good regulator (even if is is plastic).

OMG! You don't have a G250!! :shocked2:
Yeah, I know it's not shiny chrome like the 109. But there have been just a couple of technological advancements in the past 30 years. Have you converted any of your 109's to 156's? Then I rest my case -- having a balanced low pressure seat with a lighter spring was an improvement.
And venturi? Compare the flow diagrams for a 109/156 with a G250. Venturi was a good thing, too!
Yeah, there hasn't been much that's improved since the '70's, I agree. And trading pretty chrome for scratchable graphite/plastic (even if it is much lighter) is a little bit of a disappointment.
But I had to hijack this thread for a flame! No G250!!!!????
Go on, awap. Get one on EBay and clean it up.