Pressure tank valve stem

my rubber valve stem was leaking on my water well pressure tank. i tried to replace it with some others for auto tires that i had laying around but they are too big at the base to fit the hole in the pressure tank. can i get a valve stem at an auto parts store or do i need to go to a well supply?

THANKS!

I've never heard of or seen a valve stem leak like this or of a replacement stem on a pressure tank but... if you dropped any part of the old one into the tank, the 'bladder' should fail fairly soon. The new tank will have a new stem on it.

my tank lost it's air and filled completely with water. i was just going to drain out some water by shooting air in there but that's when i noticed that the stem was leaking. the only part that fell into the tank was the rubber ball on the end of the valve stem. i then plugged the hole so i can get some water but i want to install another rubber valve stem but i'm assuming that they install these things from the inside of the tank because the valve stem is way to big at the base to shove through the opening. i don't want to buy a new tank just because a 50 cent valve stem is bad.

is there a way to install a new rubber valve stem from the outside of the tank?

if i can't get a new stem in there can't i just drain the tank, plug the hole then turn on the pump and let it fill until the existing air creates about 40psi back pressure?

I can't help you with the stem, maybe go to NAPA and ask if they are made in various sizes and lube one up and stuff it in but...

The bladder has already been stretched too far, and the ball will probably get caught between the bladder and wall of the tank and stretch that spot until it pokes a hole in the bladder.

If the tank air pressure isn't right, the pump short cycles and that heats uo the pump motor until the pump fails or the thermal overload shuts off the power to it.

You need 1-2 less psi of air pressure in the tank when there is no water in the tank than the cut-in setting of the switch. I.E. 30/50 switch settings gets 29-28 psi air pressure with no water in the tank.

gary: thanks for the reply.

what i did was cut most of the bulk from the bottom of a new valve stem which allowed me to squeeze it though that hole with a lubricant and screwdriver. i then pumped air into the tank and drained the water. i then turned on the well and monitored the pressure. it shut off exactly where i wanted, at 39psi and the new valve stem is staying put. i'm keeping my fingers crossed. the rubber base on that valve stem won't hurt the bladder at all especially if i more closely monitor the tank pressure.

but you touched on something that i always wondered. is the air bladder large enough to expand to the full size of the tank without rupturing? it would seem that they would make them large enough to expand all the way without weakening.

tab said:

is the air bladder large enough to expand to the full size of the tank without rupturing? it would seem that they would make them large enough to expand all the way without weakening.

Click to expand...

It's really water in the bladder, not air which is above the bladder, and I would hope it could expand to the full size of the tank...


Rancher

I'd be careful not to stand in front of that valve stem .

Tank Air Valve!

In my 70 plus years around the drilling/pump business I've never had a problem with those valves, however they are mechanical and I'm sure they can go bad.

When there's no pressure in the system the valve, the pressure should measure 2 lbs. less than the cut-in pressure.

Just watch the system and if the pump starts short cycling, replace the tank!

thanks again for the replies. i let it pressure up then shut off the power so i can monitor it for a while. but so far that new stem is holding quite well.

let it be known though that i'm a guy who found a monarch butterfly with a bad wing but was otherwise in good shape. i superglued on a wing of another monarch which was killed by a car. it wasn't easy.... i took it outside and the darned thing flew away out of my sight. i have no idea how far he got but it was a sight to behold. next, i need to design a teeny tiny butterfly tracking device.

You didn't tell us the brand of bladder tank. Most of them when full of water are already bad. The bladder has already ruptured by that time and it will again waterlog.

I would start looking for a new Bladder Tank

bob...

yeah i will eventually install a new tank IF that bladder has ruptured. i guess the only way to tell is to let the air out, let it pressure up and see if water comes out the air valve. not gunna do that though. i'll just monitor the air pressure and if it keeps losing pressure that will signify a blown bladder. then i'll get another tank. i'm hoping that this one lasts me though the winter.

No the 'bladder' doesn't expand to touch the inside of the top of the tank above where it is attached to the bottom part of the tank.