The zincs on my Cummins often unscrewed from the brass plug when removing them. Pliers etc didn't work very well to get the old zinc out in awkward locations. To remove the zinc I used an all thread coupler sized to fit the zinc thread. Simply screw the coupler on the stuck zinc and wiggle it a bit to loosen then pull out. I rounded off the points on my coupler but it isn't absolutely necessary.
Cummins zinc tip
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Not true for me. I always did that and I even messed up the threads so it would be tighter but the zincs still mostly stuck in place.
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Well, I certainly agree with that. But I think that the OP is reporting that his zincs unscrew. Otherwise the coupler wouldn't work.
But why if he tightens them with pliers, they still unscrew is beyond me.
David
psneeld
Guru
I really don't know...all I know is that no matter what I have done in the past...tight or loose...if the general condition of the zinc is good...I can probably unscrew it...if bad...it is a crapshoot.
Pgitug
Guru
May be the type of zinc being purchased. Be careful buying "Junk" zincs. I always buy from boatzincs.com. Never had the problem.
ranger58sb
Guru
Would Loctite or something similar in between zinc and nut help?
-Chris
-Chris
Pgitug
Guru
The zincs are only a bit smaller than the pipe thread so any corrosion makes them large enough to stick.
Reusing the brass plug is not the best idea since pipe threads are tapered and designed to distort and add to sealing when installed, once.
Reusing the brass plug is not the best idea since pipe threads are tapered and designed to distort and add to sealing when installed, once.
twistedtree
Guru
This makes me wonder if your zinc isn't a bit too long and is getting stuck on something inside the cooler? I too have never had one back out of the cap threads. Break off - yes. Disintegrate to almost nothing - yes. But have intact threads and come off the cap - never.
There can be subtle issues if you don't have the right length zinc. The cooler for my hydraulics has two zincs, one in each end. If you use the standard length zinc, it seems to work fine, but as you tighten the cap, the zinc comes up against an internal divider and snaps off. But you would never know it snapped off. I only discovered this by accident and had to disassembly the cooler and fish out 3 broken off zincs. The next size shorter was required.
Oh, and beware of using loctite. The electrical conductivity between the zinc, cap/plug, and cooler body is critical. I've never tried loctite, but would suggest measuring the resistance to be sure it's OK. Have any of you guys checked that? It might be fine - I just don't know. I know that pipe sealant works fine on the plug threads, but teflon tape does not.
There can be subtle issues if you don't have the right length zinc. The cooler for my hydraulics has two zincs, one in each end. If you use the standard length zinc, it seems to work fine, but as you tighten the cap, the zinc comes up against an internal divider and snaps off. But you would never know it snapped off. I only discovered this by accident and had to disassembly the cooler and fish out 3 broken off zincs. The next size shorter was required.
Oh, and beware of using loctite. The electrical conductivity between the zinc, cap/plug, and cooler body is critical. I've never tried loctite, but would suggest measuring the resistance to be sure it's OK. Have any of you guys checked that? It might be fine - I just don't know. I know that pipe sealant works fine on the plug threads, but teflon tape does not.
psneeld
Guru
Never have I had one that wouldn't seal and I have reused them dozens of times.
They only need to be snug and aren't under much pressure.
RT Firefly
Enigma
Greetings,
I also have reused brass plugs numerous times. I dissolve any stubs of zinc that have broken off in the plug with HCl (If I remember correctly) if necessary and have even re-tapped the threads in brass plugs if the zinc refill is of a different thread configuration.
Just checked WM. Anode c/w brass plug-$6.99. Same anode alone-$2.99.
Never had one unscrew or fall out and the fact they waste away means they are working.
I also have reused brass plugs numerous times. I dissolve any stubs of zinc that have broken off in the plug with HCl (If I remember correctly) if necessary and have even re-tapped the threads in brass plugs if the zinc refill is of a different thread configuration.
Just checked WM. Anode c/w brass plug-$6.99. Same anode alone-$2.99.
Never had one unscrew or fall out and the fact they waste away means they are working.
Capt.Bill11
Guru
+1 I've never seen one that wouldn't reseal. And as mentioned you just soak them in acid to clean out the old zinc bits.
