How To Replace A Scuba Tank Valve O-Ring

Just mounted your regulator on your cylinder, turned on your air and you have an O-Ring Leak? There’s nothing worst than having to abort a dive or sit out a dive because a $2-$4  part broke down and no one had any spares.

Just as duck tape fixes everything on land, O-rings and tie wraps can fix anything when your at sea. These tiny rubber rings are crucial parts of a variety of scuba diving gear and equipment. O-rings prevent leaks at the seams of scuba gear and are a vital part of your life support equipment while diving.  O-rings are used in scuba regulators, underwater flashlights, dive computers and tank valves, and may often break due to pressure and wear & tear. It’s no wonder that these tiny rubber rings are a must have in any diver’s spares kit!

pictured above: A Mini Tank O-Ring Kit with Pick available at

However, if you aren’t well versed in the technical aspect of scuba gear, it’s only advisable to attempt to change the O-ring a scuba tank’s regulator. Leave other O-rings for experienced professionals. This is the O-ring that sits in the opening of the top of the valve of your scuba tank and seats the first stage of the regulator.

Here’s look at how to replace you tank valve o-ring:

  • Remove the old O-ring visible in the orifice of  the tanks regulator valve. For this you should use an o-ring pick which looks similar to that of a dental pick (pictured right). This is because metal tweezers or other objects can damage the o-ring groove, and even the slightest dent of the groove can cause leaks. A plastic toothpick too is a safe tool to use if you don’t have an o-ring pick.
  • Using the pick, scoop the old o-ring out and clean out the groove using the same plastic toothpick or professional pick. Look out for sand or debris and keep an eye out for any corrosion. If you spot any, you may want to have a professional take a look at it.
  • Check your replacement O-ring against the one you removed. Confirm they are of similar size and materials.
  • Push the new o-ring into the groove to replace the old one. It should slip in easily. If you have to stretch or force it, it’s probably not the right size. Never use silicone grease. This is especially to be avoided if you are using a nitrox mix (a combination of nitrogen and oxygen)-silicone reacts with oxygen. Avoid using anything other than your finger or the back eraser end of a pencil to seat the o-ring.
  • Make sure the new o-ring you just put in doesn’t have any nicks, cuts or stretch marks on it. If it does, replace it with a new one again.
  • Test the new o-ring, by attaching the first stage of your regulator like you would normally do. Slowly open the cylinder valve to pressurize the regulator. If you hear a loud pop or clap and air hissing out, the o-ring is not properly seated. Go back to the beginning and try again.

Note: Different scuba gear use different size o-rings and o-rings of different material. Scuba o-rings also differ from o-rings you may find for other equipment. specifically designed for high pressure and marine exposure. In addition, nitrox diving as well uses special O-rings that are designed to stand up to the corrosive effects of high-oxygen mixes. So if you ever need help, don’t hesitate to as a scuba expert. The staff at LeisurePro will always be glad to help you with your scuba needs. A great way to make sure you have the right  O-rings is a small o-ring kit like this Viton Nitrox “O” Ring Kit which includes replacement rings nitrox tanks as well as for most Regulators, Cameras, Tank valves, Dive Lights, Pressure gauges, and high & low-pressure hoses.

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