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I have a GDR era PT5 with the old style ball in socket rotary linkage. When doing some deffered maintenance (dissembling and repacking of the ball in socket joints with grease) I found that one of the screws that holds the linkage together is stuck. Before I waste Dana Hofer's time with this, does anyone have any at home / no heat source advice? Already attempted remedies are firm taps with a rawhide mallet, WD40 and wait, graphite based penetrating lubricant and wait, and firm taps with a rawhide mallet again.

A photo of the stuck screw is below:



Thanks!

Someone may have put Loctite on it, but I had a stuck screw like that on the St Pete I just sold. I just got a better screwdriver with a better handle along with a better tip, dug in like hell, and busted it loose. Quite often, you can bust them loose by slightly tightening them, and then they will turn backwards.

Put it back on the instrument, so you have something against which you can push.

WD-40 is a perfectly useless substance. Go get some PB Blaster, spray a very small amount in there, heat it too hot to touch to where it bubbles a little bit, spray a little bit more in there, and wait.

Offering this advice will trigger other people who claim that their penetrating oil is better, "The Science" backs up their boasting, etc. and blah-blah-blah, but - regardless of how much better theirs is supposed to be, this stuff never lets me down.

@Dents Be Gone! could be correct re: the inside threaded part having been distorted...ok...so it might be worth a try to put a regular medium/medium-large slot screwdriver in that bottom slot and spread the metal slightly (??)

Just to add to everyone's advice:

It might make it much easier if you put the linkage in a vice(smooth jaws) to hold it for you while you turn the screw out.
If it is locktight or corrosion, then best to lightly warm the outer part of the socket as you are turning. I would also recommend using a screwdriver that fits as tight as possible to give the most power and prevent damage.

Worse case, if Dana doesnt have any extras, hit me up as I have a few boxes of spares.

Thanks to all for the helpful advice! The @bloke higher horsepower screwdriver + back on the instrument + moving it a bit the wrong direction first did the trick.

daktx2 wrote: ↑Sat Aug 12, 2023 11:51 am Thanks to all for the helpful advice! The @bloke higher horsepower screwdriver + back on the instrument + moving it a bit the wrong direction first did the trick.

I'm glad it worked out for you.