Blakes Seacock Problem

Wigeon

Wigeon

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Hi
Have a problem with a Blakes Seacock outlet to my sea toilet. Last trip out I noticed water slopping around in my small heads compartment. Traced problem to be sea coming in around shaft of Blakes Seacock Toilet outpipe. The cock is sealed to hull, no problem, but it seems engine vibrations had loosened one of the nuts holding on top. Its one of the older type without the greasing nipples, thus :
15scock.jpg

I've temporarily (hopefully) stoped leak, by tightening down both bolts to max. Thus cock (in closed position) makes head unusable, but at least the sea has stopped coming in. I know about stripping cock and regreasing when boat hauled out for winter (I only did it last winter!!!), but wonder if anybody has a clever idea to see me through the season, without a mid season haul out or beaching for a tide? I'm a bit worried the whole thing could come apart mid voyage
ALSO, CAN ANYBODY TELL ME IF THE NUTS HERE ARE LOOSE FITTED OR SHOULD THEY BE CAPTIVE TO THE BOTTOM PLATE. Mine clearly are not /forums/images/graemlins/frown.gif
ALSO I USED BLAKES GREASE LAST TIME AND IT SEEMS NOT TO HAVE LASTED ANYTIME AT ALL. IS THERE A BETTER PRODUCT?
 
As far as your nuts are concerned another diagram on the BLT website shows them as separate not captive. Look just next to the grease nipple, not at the one floating about to the right

scockdia.jpg
 
Mmm. thanks. bit of a design problem there since the body of the bolt is not long enough for a locking nut. I think the previous owner might have used Locktight, and I messed up the very critical setting when I last stripped her. Seems regreasing a Blake is not always a good idea
Still open to others suggestions
 
Longer screws with locknuts?
Longer screws put in the other way with nuts and locknuts on the top?
 
It's quite some time since I last worked on the Blake sea cocks on Como but I'm sure that the fixed bottom plate was tapped so the bolts screwed in to it and the nuts were then used as lock nuts. Maybe someone else can confirm.
 
Not an expert on these, but have lived with them for many years.

The bolts that you have tightened are threaded into the fitting, with a locking nut underneath. Thats how mine work anyway.

I have found that the bolts might seem to be a little loose, but locking nut underneath should keep them safely in place.

The 'art' is to have them as tight as you can, and still be able to turn the stopcock. Of course when the boat is out of the water, a good cleaning and greasing enable the stop cock to turn relatively easily and be tight.

I have found that after re-assembling the stockcock, put a little grease up the tube from the outside, and rub it into join between the stopcock shaft and its cylinder. This prevents or slows down any water entry between the shaft and cylinder.

However, all you can really do for now is to loosen the bolts until you can turn the cock, and they don't leak. You might be able to take out the stopcock if you have a large bung to stop up the hole!! We do it for the paddlewheel on the distance log!!. Not sure that I would do it though. (unless desperate)

If you were brave enough to do that, then you could at least clean the stocock shaft, and re-grease it. Whether that 'repair' would last long I would doubt it.

I don't use Blakes grease. Not sure what brand of grease it is, but something from the local chandlers.

(Another daft idea!!!)

Mj
 
Yes mine on my old boat were fitted into a threaded bottom bit so the nuts below were in fact acting as locknuts, never had any problems with them, just cleaned them off once a year and regreased with seacock grease, can't remember the make but it was mint green in colour. Might have been Blakes. Are the tapers in good condition?
 
Oh~ Oh!.
It appears from your info, if correct, that mine has stripped the thread on one of the bolts or the bottom plate, and its only the nut done up to max, is stopping me from disaster.
Anybody ?
 
In all the Blakes seacocks that we have had the nuts have been lock nuts. The flange on the body of the seacock is threaded and you tighten up the nuts to lock the bolt in position once you've bedded the cone in and its nicely on a film of grease so that it can be moved easily. (Should be able to almost move the handle with one finger - firm but not loose.)

If your threads are stripped, you could get a longer bolt and two nuts? Make sure the bolts are bronze to match the body of the seacock!
 
I used Castrol water pump grease on mine, after despairing with other products, which soon washed away in use. It is yellow and really thick stuff. God knows if it is still available,its 10 years ago I had the boat with these seacocks. As others have correctly said, they work best when tightened gradually to the point where movement is stiff.But do check again as the grease extrudes gradually. They did not leak even when fairly loose, with this grease.Good luck, the 2nd lock nut idea may work or a half thickness nut may fit between the flange and the body, with another full nut underneath.(if the threads are stripped in the body! Good sailing.
 
Oh, just remembered, if any are stuck, when boat is ashore, remove the fixings inside and insert a long drift from outside, give it a good tap with a hammer and the conical part will separate.Trying to twist a stuck seacock may break off the handle.Purists will grind the cone and the body with valve grinding compound to achieve a perfect mating surface, I also heard of Brasso being used for this purpose.Nice to start off with the items clean, before reassembly. They will probably outlast the modern equivalent.Watch for pinkness or porosity, as this can indicate electrolytic damage or Galvanic action. Unconventionally, I banged mine regularly with a lump hammer just in case they were on the point of failure!
 
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Yes mine on my old boat were fitted into a threaded bottom bit so the nuts below were in fact acting as locknuts, never had any problems with them, just cleaned them off once a year and regreased with seacock grease, can't remember the make but it was mint green in colour. Might have been Blakes. Are the tapers in good condition?

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Thought so. I even used a sort of cutting paste to Re-seat barrel of cock into taper. Cleaned that off, and likewise think the mint green stuff is the Blakes grease I used. Its almost as if the Blakes grease has dissapeared, and now I cannot get a position where the bolts are just slack enough for cock turning without the sea coming in shaft. I'm begining to believe that Blakes knew about this, and so manufactured the new types with the grease nipple so one can top up grease seal without dismantling.
Wish I'd never disturbed it now. There was no real reason, I just felt last winter that I should go over everything and do all those maintainance jobs. I guess the moral is, if it aint broke dont mend it !!
 
[ QUOTE ]
I used Castrol water pump grease on mine, after despairing with other products, which soon washed away in use.

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Thanks for this. Sort of chimes with my experience that Blakes own grease is not a wonderful product. Seems pretty clear now that vibrations having slightly slackened one bolt, it took no time at all for the grease to be washed out, and now I cannot get a working watertight condition. Ill ask around boatyard for the Castrol product, cheers
 
In a properly fitting seacock, the grease cannot get 'washed-out'. I have an ancient SL sea cock which is pretty identical to the Blakes. I use Blakes Sea Cock grease and it is fine. Mind you I've had the tube 15 years. You don't get through a lot. It is not 'mint green' in colour but dark brown and pretty thick. I suspect that you need to lightly grind the cone again this winter and take care to remove all the grinding paste. Key to success is not to tighten down the ring too much or you squeeze out all the grease. If you need to tighten it to much to stop leaks, the seating needs a light regrind. The idea of the nuts unscrewing through vibration seems bizarre (and I speak as someone who had a solidly mounted engine), just how much vibration have you got? They are just not that loose. We have had a debate on this forum before about how tight it should be screwed down and the general view was a light finger and thumb ought to be able to move the lever and no leakage should occur. Blakes seacocks have been around for 50 years and the grease nipple is a response to the need to be able to service (grease) the cock in the water not to any design fault.
 
If you are unable to get it to seal even after stripping it down and regreasing, then there is a possibility that the cone or body are slightly oval. If it sticks at one particular point when it turns, but seals if you harden it right down, then it needs a heavier regrind next time you have it out. I did this on a Rowe unit (same basic design) until it got too stif then replaced it.

Not sure what causes it, but if you do get it ground in well a nd keep it greased I think that will do the trick.
 
your description doesnt sound much more than the routine settling down of the seacock after being taken apart and re- greased. as has already been said, the trick is to get the nuts tight enough to prevent leaks but still allow you to turn the handle which requires equal tension on both of them. so unless I am misunderstanding what you say and you have stripped one of the nuts, my inclination would be to slacken them off a little bit and turn the handle. see if it starts to leak again.

if it does, can you not at least tighten up with the khazi valve in the open position. no doubt the H&S and the insurance companies would say thats a definite "no" but I've known sailors who never shut any seacocks over the season.

your decision . incidentally, Blakes grease is deffo one of the best. used to use it on my outdrive leg because it stuck there way longer than anything else.
 
Never considered myself a 'purist' (see above) but IMHO you'll never achieve a good seal and finger-touch operation unless cone and body are ground to a fair fit. It takes a few minutes and lasts for years.
 
The Blakes on my boat must be 32 years old. I lap them every time I have the boat lifted out, which is every three years. It does take more than a few minutes to do it with medium and then with fine.

It is important, however, that this seemingly simple .job is done properly This means not applying undue force downwards, keeping a light hand, lifting the cone and turning 90 degrees from time to time and cleaning religiously ALL traces of paste before applying the next dabs.

For greasing I used to use Keenol, now I use PBC. The bolts that hold the cone collar down are only done up finger tight before the locking nut is tightened. The lever should be turnable by just applying the tip of one finger.

When the cone has been properly lapped it will not leak.
 
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