Lubricant for seacock

[FrankTugw2ell]

My thruhull began to drip when I closed the seacock, and I suspect it is out of round. I pulled the insert in the seacock out and cleaned it and the seacock (in the water--luckily my bilge pump was up to the job) and replaced it, but it still leaks unless I leave it in open position and screw the nut so tight that I can't close the valve without loosening the nut. Have I used the wrong lubricant? and what do I do if the seacock is out of round (having been left in open position for several years, I guess)?

[RichH]

Go to an automotive supply store and get some 'fine' valve grinding compound - this will be used to re-polish the barrel and the plug. Remove the plug, apply the compound to both the plug and inner part of the barrel and turn (rotate - dont just 'rock-back-and-forth') until all is cleaned and repolished ... dont get carried away or the plug wont fit and the nuts will be too 'far away' to the side of the barrel when assembled - polish dont 'grind' deeply into the surface.
(If you do this in the water, jamb plumbers putty into the throughull to 'stop the flood' -- its BEST to do this when the boat is hauled).

The BEST sealing compound (auto store stuff) for the tapered plug valves is 'waterproof' wheel bearing grease ... try to find a WB Grease that has 'fiber added'. Apply to the barrel and plug, assemble the plug to the barrel and 'slightly tighten' the nuts and washers of the plug to the valve ... but NOT so tight so as to squeeze all the grease out of the valve .... just tighten so that there is a 'wee little bit of drag' when you rotate the handle - not so loose that there is no drag but not enough so that you dont squeeze all the grease out.

[sailingdog]

You'd be better off replacing it with a ball-valve seacock.. The tapered plug type ones are not as good for marine use, as there is no guarantee that they are actually closed, and the handle doesn't provide a visual inidicator as to the status of the valve.

For lubrication of seacocks, I'd recommend using lanocote or anhydrous lanonlin.

[pigslo]

Actually Sailingdog, the tapered do have a lever handle that indicates open or closed. I believe you are refering to the gate valves that you cannot tell if they are open or closed.

[sailingdog]

Yes, my bad... his description could be describing either a gate or a tapered plug valve. I'd still recommend going with the ball-valve rather than the either the gate or tapered plug. But that's my personal preference.

[pigslo]

I had one gate and5 tapered that I replaced with Conbraco bronze body with stainless ball valve. Maintenance recomendations range from nothing to grease once a year.

[heron237]

Nothing wrong with a tapered bronze seacock, they're easily inspected and serviced and if you clean and regrease them periodically they'll give years of service. Whereas a ball **** style valve, has more parts, plastic seating surfaces and disimilar metals....

[RichH]

Stainless steel is NOT a good metal for sea water, especially the polished surfaces of a ball. Chlorides WILL attack stainless; and, If the ball ever begins surface corrosion it will quickly wear the polymer seat .... and the valve will leak no matter what you do with it - open or closed it will make NO difference.

[sailingdog]

I'd go with BRONZE ball valve seacocks... I don't see how a ball valve is more complicated than a tapered plug seacock. Marelon, the only plastic I would use on a below-the-waterline through hull is reinforced, and quite durable.

I'd also replace the through hulls with titanium ones...but that's just me.

[flcapt]

The procedure for re seating a proper tapered sea **** with simple valve grinding compound is correct. I prefer to use TefGel as the lubricant. It is a little stiff but does not wash out easily and reduces the de-zincification of the bronze surface that causes the leakage. I find Tapered valves preferable to ball type. They are easily serviced, even in the water if necessary. Ball valves have a limited life and must be replaced if neglected. Once they stiffen they do not recover. The labor and parts to remove dis-assemble and reinstall is more than the cost of the valve. Which is not cheap either. The movement away from plug valves is sad. I Hate having to tell customers that they need to spend $1000 plus on parts and labor to replace a 8 year old ball valve when a 50 year old plug valve could be over hauled in about an hour. If a plug valve is stuck the packing nut can be loosened and the the small end of the taper tapped with a mallet and a block of wood (to protect the threads) and the taper will release. With a frozen ball valve it is all over.