How to prevent seal damaging SS shaft sea water pump?

[lucseawalker]

I have a Jabsco 3270-0001 sea water pump on my engine and every few hundreds of hours, the seal on the seawater side of the pump starts leaking



When taking the pump apart, I always find a grove in the SS shaft, made by the lip seal on the seawater side (rarely and barely by the lipseal on the engine side in engine oil!)


If installing a new seal on that damaged shaft, it won't even last as long and leak again with a shaft with a deeper groove. So I am forced to replace that SS shaft at over 130 US$ each time !!


I am not an engineer but it seems to me that only the seal should wear off and be replaced, not the expensive shaft! Speaking with many cruisers around, it seems as everyone has pretty much the same problem.


Has anyone experience having a shaft manufactured in a different material than the soft SS used by Jabsco. Titanium?? Carbon? Composite?



Or using some kind of expendable sleeve?


Another idea would be to use a different kind of mechanical pump or a electric water pump ... Any ideas or better any solution successfully implemented? I guess it has to be a pump that could run days non-stop without overheating ...

[jamhass]

2 options:
1. reassemble with the shaft slightly shifted to have the seal run in a new spot.
2. have a machine shop weld and regrind the shaft. In some places (Mexico, for example) this can be done inexpensively.

[model 10]

A Speedy Sleeve will fix the shaft for something like $30. Remove the spring from inside the seal and use nothing or an O ring instead of the spring.

[Sailorman Ed]

Ecos - thanks, just what I was looking for.
Ed

[lucseawalker]

Thanks for these 2 suggestions ...


Perhaps I can find a way to slightly move the shaft one way or the other .. will check into that.


As far as shop weld, I had that done in the Philippines but it did not work at all. While that spare pump was in storage for just about a year, the welded spots rusted and the pump leaked right away Perhaps they did not do the job well ...

Originally Posted by jamhass

2 options:
1. reassemble with the shaft slightly shifted to have the seal run in a new spot.
2. have a machine shop weld and regrind the shaft. In some places (Mexico, for example) this can be done inexpensively.

[lucseawalker]

Originally Posted by Ecos

A Speedy Sleeve will fix the shaft for something like $30. Remove the spring from inside the seal and use nothing or an O ring instead of the spring.

I just read the SKF Speedy Sleeve pdf and it sounds exactly like the best solution .. perhaps I will finally be able to avoid buying new shafts and get more hours of no leaking pump!


Thanks for this excellent tip! Power to our many brains sharing on forums

[RaymondR]

Originally Posted by lucseawalker

I just read the SKF Speedy Sleeve pdf and it sounds exactly like the best solution .. perhaps I will finally be able to avoid buying new shafts and get more hours of no leaking pump!


Thanks for this excellent tip! Power to our many brains sharing on forums

I have used these on the output shaft of a gearbox and they worked very well. The carbon steel shaft had rusted under the seal lip allowing the oil to drain out and the gearbox seized. I decided then that it would have saved a significant amount of cash to install the SS sleeve before the shaft had a chance to corrode.

[Bean Counter]

Have used SKF speedi sleeves on sail drive shafts with same groove issue - fixed the problem.

[Lepke]

If you do have a shaft repaired, the best, long lasting way, is to have it hard chromed. People that repair cranks do it. The shaft is turned down slightly in the seal area and chromed back up, then polished. It's also done on journals on heavy duty cranks in engines that will be rebuilt many times. Before products like speedy seal I had many shafts chromed, none failed. Welding usually fails because they often use the wrong stainless (or other metal) filler.

Hard chrome is different than shiny chrome.

[model 10]

[QUOTE=Lepke;
Hard chrome is different than shiny chrome.[/QUOTE]

In aviation, it is common to chrome cylinders and crankshafts. In the case of cylinders, they can apply a chrome surface that holds oil. Somewhere in the chrome process they switch polarity and it causes the surface to crack. The cracks hold oil, amazing.