Diesel leak draining fuel tank

[Boeingdr]

I have a slight weep of diesel from the fuel cock from the base of my diesel tank. This has been the case since I bought the boat but it has been sufficiently small that a rag around the tap has soaked up the fuel.
I have just had a fuel feed attached downstream of this to a new Eberspacher heater.
Since then an amount of fuel seems to be collecting in the bilge (not sure if this is combined with a rainwater leak which I have just tried to repair from the cockpit table fitting above).
If the leak has got worse I may be forced to replace the fuel cock.
This will involve draining the tank, its a pretty old fuel tank I think, I am worried that draining it will disturb all the contaminants at the base of the tank and cause problems with the fuel system later.
Does anybody have experience of draining the tank, advice, warnings etc..
Thanks

 

[JonJon]

Oh yes! Draining yer fuel tank, depending on where you doit from wont disturb the crud at the bottom of the tank. But Might be a good idea to get most of it out anyway! My fuel drain off cock which was also the emergency shut off cock leaked like a sieve not externally but across it. I was very perplexed as to why I couldnt apparently shut off the supply to the engine. Cock was useless (if you'll pardon the expression).
Not familiar with your machine but you definitely need to get in there and find out whats leaking and why?

 

[SvenglishTommy]

I had exactly the same problem. I just drained the tank and replaced the fuel cock, didn't see any sediment when I drained or when I refilled. This is on a 30+ year old built in tank.

My plan was to sort out the leak(s), then bleed/run the engine for a while, and then change the filters, but the filters were pretty clean anyway so I wouldn't worry about it.

 

[Boeingdr]

Ok thanks for the advice, think Il go for it then.

 

[dolphin]

i have the similar case - leaking the tank! i decide to change the tank as if the small, even unnoticeable leaking, increase, and usualy this will happend in the moment when you dont like, the bilges will be full with diesel!
just a friendly warning - this is a very hard job, i dismantle everything in fore part of the boat to take the tank out!
also the draining of the tank was not the pleasant job.
hopefully, now i am in proceed of reverse work but still remain a lot more.
but i strongly recommend to change, before the actual leaking commence!