Stuck screw

[Shaman]

Trying to change out the head on a shurflo 8000 series pump, and one screw is not cooperating. I tried banging on it on both sides, tightening then loosening (it does the tightening really well), heat( screw goes throught plastic to metal), and heat with wax. The wax went through, but the screw won't go past a certain point. I can tighten and then loosen it back to the original point, but can't get it looser than that. In Japan, so about the only I might have access to is WD-40. Read about coke, and acetone and ATF, but don't know where to get Acetone right now.

 

[Bob Woods]

don't know where to get Acetone right now.

Look for nail polish remover

 

[dparm]

Impact driver?

 

[doitmyself]

HMMMMMM, can't delete my post, but can edit it still.

I took a look at a diagram and see that the screw seems to go into a nut inbeded in the "ear" of the pump head. Try to find a plastic safe thread penetrant and work slowly.

Seems like you can just break it off and then drive the screw and nut out the back side.

 

[doitmyself]

On second glance, I see there are other configurations of the 8000 model, so maybe my idea is wrong. Sorry.

 

[Shaman]

MIne is the pump at the top, and the offending screw is like the upper most screw. It is threaded into the center part, and I don't know if an impact driver would do anygood, or if it would just strip the head completely.

 

[Shaman]

Bought a bigger screwdriver, and it still didn't want to come, so because it would get tighter but not looser, I used the screwdriver and had the wife spray a silicon penetrant on the opposite side, and just went back and forth for about 2 minutes, giving it a crank loose to see if it would move. Finally, and suprisingly, it did start to loosen, so I got it off, replaced the screw, and used antiseize in case I need to remove it again.