Topic: KH Proportioning Valve stuck

[k-code]

Anyone have a trick to free up the adjuster screw on the proportioning valve?
All set to take apart and rebuild and the adjuster is frozen solid. I've soaked in penetrating fluid for 3 days, applied heat to the body, soaked some more, got fluid inside the bleeder and line fittings and still won't budge.
Thanks,
Andy

[CharlesTurner]

Might try a brass block to cover the end and give it a few whacks with a heavy hammer.


Otherwise, keep soaking.

[sgl66]

Not sure what penetrating fluid you're using, PB Blaster is the one that works best for me. Sounds like you're coming at it from both sides, try squirting some in the weep hole on the bottom too. Also try to tighten it, anything to move the threads initially

[k-code]

Deep Creep is the stuff I'm using. It's very good. Yeah it's been soaking for 4 days now, fittings, weep hole, everything. Gonna try heat again and hammer tomorrow and if that doesn?t work, I'm done. Too bad as it's original to the car.

[sgl66]

I've had success with heat many times for nuts and bolts but thinking about this more, the core of the prop valve is probably acting as large heatsink and not expanding much while the hollow adjusting bolt can expand more easily into the core, if it expands at all.

This is an old thread talking about applying candle wax after heat to get into the threads and act as a lubricant. It's the same concept as sweating copper pipes https://bobistheoilguy.com/forums/threads/liquid-wrench-vs-pb-blaster-vs-seafoam-deep-creep.47088/

Did you also remove the c clip and plate from the rear to get access to the inside?

[ruppstang]

I read a report one time that showed that a 50-50 mix of acetone and ATF out preformed all commercial penetrating oils. 

[Murf]

You might try soaking the valve in some Evapo-rust. Since you can get the liquid on both sides of the plug I think you may have a  good chance of defeating the rusty bond.  It  removes rust very well.  Things having brake fluid in them are rust magnets and require extra attention to break free. Good luck!

[k-code]

Yes I did remove the clip but the cap isn't popping off. I've given it a couple taps with a small brass punch and it hasn't moved at all. I assume you need access from the other side to push it out?

Soaking in rust remover is a good idea, I'll try that.

[sgl66]

Yes I did remove the clip but the cap isn't popping off. I've given it a couple taps with a small brass punch and it hasn't moved at all. I assume you need access from the other side to push it out?

Soaking in rust remover is a good idea, I'll try that.

The c clip presses the cap against a rubber O ring to seal the rear but I suspect there was moisture in the fluid that has caused rust to form now holding it in place. I would heat the cap and tap it to try and break the bond, the worst case is you melt the O ring which will need to be replaced anyway. I don't think you'll get enough Evaporust in through the brake line connections to do the job. Once you get the cap off, you will probably find the valve also has rust on it and then you'll be in a better position to use Evaporust.

I suspect the core will need to sleeved and if that's the case, White Post may be in your future https://whitepost.com/#hometop

BTW, my earlier comment about candle wax, it may still work but thinking about it more, I would hold off because it will block any penetrating fluid/Evaporust you may try. I would focus on removing the rear cap first.

Also, +1 on ATF/acetone

[CharlesTurner]

Blocking one of the brake line connections and using an adapter to pump grease in with a gun would pop the rear plate off.

[k-code]

Thanks for the all the comments and suggestions.
Got up early this morning, soaked the valve in rust remover for 4 hours, a couple taps with a rubber mallet, into the vise and it finally began to turn. Wasn't easy but it freed up.
What a mess inside. The spring was frozen in black muck. Surprisingly the critical surfaces aren't too bad and looks like it will be ok. Inside the adjuster, where the spring sits, is ugly and will need some work with a dremel and small wire wheel.