Rebuild leaking fuel system ball valve?

I won't be able to get to this project until I get the fuel low enough to transfer all into the starboard tank. I was already going to re-plumb the area because the sight glass (plastic) does not have a shut off. The sight glass only registers when the fuel line is open and in use. The new problem is that the ball valve has developed a really slow leak, maybe from not having been used for years and then recently being thrown 25 times. Probably a drip a day on the diesel diaper I put underneath.

The leak is coming up from the handle stem. I assume that there are O-rings inside that have worn and no "packing gland" type of washer that can be tightened around the stem? Does anyone have experience with rebuilding a ball valve? At $10 for a new one, is it worth rebuilding?

Mark

I'd just replace it. Haven't needed to do any of my fuel, but did both of my water. Quick. Easy. No uncertainty. Done.

Just replace it.

Take the handle off. Below the handle will be a nut you can tighten. Not too much or it will be too tight.

Be careful with "big box" ball valves, they will have tapered threads and it is unlikely that you have tapered onboard. Check that out first.

I would just replace it. Why mess around with it and maybe still have a leak.

Pulling that valve will be very messy, even with a shop vac. If tightening it works...?

Xsbank said:

Pulling that valve will be very messy, even with a shop vac. If tightening it works...?

Click to expand...

Seems to me that at least attempting to tighten the nut is a no brainer.

I agree with at least take the handle off and have a look to see if there is a nut that can be tightened. If not then replace the valve.
/Ball valves, good as they are, are not foolproof and can develop problems.

At my previous jobs we used hundreds of them and once in a while there would be a goofy one.

If you do replace it either reuse the nipple or if not then use either a SS nipple or a plated steel nipple. NO brass or bronze nipples. The SS or steel nipple will be enough isolation to protect the tank

Wasn't there a poster a few years back that had good luck plugging the vent and pulling vacuum on the tank then removed and replaced of the valve?
HOLLYWOOD

'Twas not me but I have done that and it worked fine but the tank was a WHOLE lot
SMALLER and I had run it down.

But you must have a darn good seal where the vacuum is attached.

If you are going to try to tighten it, be prepared to replace it in case the leak gets worse. Sometimes when you try to fix things you actually make it worse. So I would have a new valve on hand and the tank as far empty as possible and then hope for the best. Good luck.

Some ball valves have O-rings, not a compression type packing gland with a nut. Can't see if the valve in the pic has a nut, but from what the OP described, it does not. An O-ring stem seal won't heal, nor is there any adjustment; it will only get worse. In 30 years in the plumbing trade, can't say I've ever rebuilt a ball valve, or any service valve, for that matter. Not even a consideration. Replace. For fuel service, I'd avoid the box store inventory, go to a plumbing supply house and get a decent one.

I would certainly try tightening the stem nut first. Removing the valve is going to be a PITA.

Maybe you could take a look under the nut to see if you can repack it or replace an o-ring without removing the valve.

If you do have to remove the valve, just replace it.

Looking at the photo again, it will be a bugger replacing it due to the hard piping it is attached to. Hard piping is nice until you have to work on it. You will probably be disassembling quite a bit to replace the valve. Per the above advise, buy a quality valve to replace it with. Good luck.

At your local plumbing supply you can purchase a similar valve that is used on home heating oil tanks ,,

that will automatically close if there is a fire. Not boat priced

https://ordering.fwwebb.com/woitem/...MIrM_jvZ6j7gIVa_7jBx18uwDdEAQYCyABEgLth_D_BwE

It seems like just dealing with a single drip per day might be easier.

Turns out that there wasn't a nut underneath the handle to tighten. But... under the handle was a short length of steel tube around the handle stem. I carefully lifted that out and could see that it sat on an o-ring or packing material of some sort. All that was required was to tighten down the handle and that forced the tube on to the packing material. Issue solved (for now).

Good outcome, Marco.
If you will be buying spares I would suggest avoiding any valve not rated for fuel.
I always get these parts from McMaster-Carr or a similar company that lists all the
pertinent data about their various components.

I wouldn't use any old ball valve especially brass, I use these.