Seized brass fittings help!!!!

[Tibs]

Hello all!

Need help with the brass fittings on my Gilmour spray gun that I use for foaming the car. The horizontal dilution adjustment 'bar' is stuck. I just cannot turn it at all.
Tried all sorts, but still no joy.

Any ideas/tips/advice?

Hope someone can help and get me back to the detailing routine!

Cheers.

[Tibs]

Can't really get any heat on it sadly.

Thanks for the suggestion though.

Any more help guys?