Seacock

[KMM]

I have a Seamaster 925 on which the outlet from the head has totally seized and no amount of force, heat, plusgas etc seems to work.
Can anyone help with either suggestions to free off, or help identify the fitting if I have to purchase a replacement? It is a bronze casting, being one piece skin fitting and valve, attached to the hull by a 4" square flange with outer plate and four through bolts. There is a top cover secured by three bolts through which the shaft emerges vertically, and under which there is rope packing as in a stern gland. The inlet from the head is to the side of the body.
There is no room to replace with the common off the shelf fittings available in local chandlers.

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[ccscott49]

You have a blakes seacock, take off the top three screws and p[late, then try again moving the tapered plug, which should have a square on top and a handle to fit, it should come out. Failing that, get under the boat with a brass drift, which will fit in the hole and hammer, then twack the brass drift through the hole, this should shift the valve. Failing that, undo the four securing bolts and remove the whole seacock, then you can work on it on the bench, it will come apart, then you can clean it up and grease it, with the correct grease, operate it evrtime you leave the boat and it will still be working in 20 years.

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[dickh]

Sounds like a Blake seacock - lots of threads on this subject recently. Try a search. If it's as stuck as you say, you'll have to remove it completely to unjam it on the bench. Alternatively, slacken off the three screws around the shaft, then using a piece of Ø1" dowel(or larger) knock the centre bit thro' into the hull. Almost certainly it will be a taper plug and this will need reseating with grinding paste - but make sure all traces of paste are removed before refitting. If you decide to remove the whole fitting between tides, make sure you have an emergency 'clamp/bung' to fill the hole when the tide returns!
If it is a Blakes you have the real McCoy - don't replace it with cheaper inferior substitutes found in chandleries....
Good luck.

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I'd rather be sailing... /forums/images/icons/smile.gif

 

[DeeGee]

nice coincidence. My boat is out for its annual titivate etc. My heads outlet seacock is Blakes and was locked up. I removed the upper, coned, part and cleaned it up pretty well. The 'hole', through-hull, part was virtually impossible to clean up [bereft of ideas] and when I replaced the upper part, well greased, it went hard to turn with v little tightening of the holding bolts. There may be some special technique to this, other than leaving it relatively easy to turn and then taking up the slack when launched and visual inspection will confirm if leaking or not. I am going down this evening to do a couple of last minute jobs before relaunch tomorrow, so any further comment on this would be welcome.

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[Mirelle]

Tale against myself....

Quite a few years ago, I put the old girl on the posts, scrubbed and painted the bottom, removed the seacock cones as described above, greased them, put them back and....halfway down the Wallet, I went below to check the chart, and stepped into water!

I had been so terrified of over-tightening them that I had left them too slack.

I do as Richard does - wipe the grease off, apply a smear (really very little!) grinding paste (from car shop) put the cone back in, waggle the handle a bit, take it out, remove grinding paste and apply grease.

However, there are those who counsel against this, saying it wears out the bronze in no time.

The iron law is always operate each seacock whenever you are on the boat.

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[ccscott49]

Re: Tale against myself....

I would never use grinding paste on a bronze seacock, a clean up with a wire bottle brush, on a leccy drill does the job admirably, wire brush the cone and grease and refit, tighten the screws, they should have lock nuts, until the handle is just stiff to turn, no probs, I have 12 of them!

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[tome]

Re: Tale against myself....

Blakes recommend a medium grinding paste. Using grinding paste ensures that you end up with properly mating surfaces on both the cone and body. Cleaning with an electric drill is definitely a no-no! You could end up with leaks or a seized valve.

When tightening (after greasing) you should tighten the screws evenly whilst operating the handle, and stop when you start to feel friction. Then tighten the locknuts without disturbing the screws.

The heads outlet is prone to bacterial pitting and generally the worst. I replaced mine this season.

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[ccscott49]

Re: Tale against myself....

I've cleaned mine with a bronze wire bottle brush for many years and never had a problem with mine. But if you say so OK. I'll still do it my way and not use grinding paste, you never get all the grinding paste out of the pores of a soft metal, simple engineering principles, thats why proper bedding plates are made of porous cast iron, to hold the paste.

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[KMM]

Thank you all for the advice. Now that I know what I'm dealing with, and have had a look at Blakes exploded diagram, I 'll dry her out and have a bash (sic) from underneath. Will make sure I grease it properly when reassembling.
Thanks again.


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[tome]

Re: Tale against myself....

Just passing on the advice provided by Blakes - I have a service sheet they sent me somewhere. Agree you have to be thorough about removing the grinding paste, I use paraffin and lots of rag. You'll know if you haven't been thorough enough with cleaning as you can feel if it's smooth when you operate the valve.

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[ccscott49]

Re: Tale against myself....

Yes, I've read somewhere in their stuff about the grinding paste, but I still know it's, engineering wise, wrong. But never mind, I've never actually needed to re-bed a valve in yet on a blakes, a clean normally does it for me. I cant see how greased bronze/bronze is going to wear appreciably anyway, it's not as if it's a bearing on a revolving shaft or whatever.

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[andy_wilson]

Try this...

If it is a Blakes it will have a grease nipple on it.

Get a good quality grease gun with a flexible hose, and some sea-cock grease (you will need both in the future for regular maintenance).

Apply copious amounts of grease, the presuure generated is enormous and may well force the mating surfaces apart without need for dismantling.

I had a seized Blakes that this worked for. Over the course of a few visits (and re-applications) the valve became freer and freer until it was only just binding and proved quite servicable.

Often removing them can be a butchers job as the nut sieze tot he threads and the fitting is bonded so well to the backing plate it rips it off the hull.

Try a grease gun first.

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[vyv_cox]

Re: Try this...

Only the recent ones, I think. Blakes have hauled themselves into the 21st Century by the addition of the grease nipple, but mine, fitted in 1985, were not thus equipped.

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[ccscott49]

Re: Try this...

You can retrofit, you need a 21/64 drill, 1/8 BSP tap and a grease nipple, bronze if available. Drill into the grease trap area, tap the trheads and screw in nipple, easy, if the are out of the boat, or dismatled in the boat, if you have room.


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[KMM]

My thanks to all who contributed to helping me with my seacock problem.
Following your advice, I have now successfully released the valve, reseated with grinding paste and greased with Blakes grease. Now working beatifully smoothly.
Thanks, much appreciated.
KMM

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