How to Replace Dampener Seals on a UMG

Posted on Sep 08, 2017 by Kathy DeGlandon

Crown's Flange UMG's will withstand the harshest industry conditions, and with regular maintenance they will last for years. It is important to follow a regular maintenance schedule where the diaphragm cup, and o-ring seals are checked for nicks, cuts or tears. If these all important items do wear, they can affect the gauge's accuracy. When it's time to replace the seals, use our UMG Repair Kit CKT-UMG following these steps will ensure that your flange UMG will perform at its peak. 


Items Needed to Replace Dampener Seals

  1. UMG
  2. Black O-Ring and White O-Ring
  3. Flathead Screwdriver
  4. 3/4" Socket

Replace UMG Seals

  1. The dampener screw is located on the dampener assembly below the gauge face on the flange. Loosen dampener screw with flathead screwdriver. Once loosened, remove screw.

  2. Using ¾” socket, break seal on hex nut and loosen. After hex nut is loosened with ratchet, finish loosening with hand, and remove. Note: Fluid will leak from dampener when hex nut is loosened.

  3. Remove dampener stem. If dampener stem cannot be removed by hand, then  use needle nose pliers. Caution: Do not use excessive force or pliers with sharp teeth to remove dampener stem. Excessive force can damage stem and cause gauge to leak.

  4. Using a pick, fingernail or screwdriver, work black O-ring out of grove and remove. Remove white O-ring. Because it is split, it will be easier to remove.

  5. Replace black O-ring onto dampener stem first, by sliding it on until it rests in the groove towards the top of the stem. Slip white O-ring past black to fit behind it. Note: White O-ring holds black O-ring in place. Black O-Ring keeps fluid in gauge.

  6.  After O-rings have been replaced, lube dampener stem with silicon-based grease. Note: Lubricant is needed to keep O-rings from being cut when replaced in flange.

  7. Replace dampener stem. Dampener stem is seated properly when is pops into place.

  8. Replace hex nut and finger tighten. Tighten completely with socket.

  9. Recharge fluid in UMG. For more information about how to recharge UMG, refer to How to Pump Up Flange  UMG.

How to Set Dampener Sensitivity

After gauge has been replaced on pipe . Check the sensitivity for optimal use. After dampener has been tightened and you have backed off two turns, check for pointer bounce.

Too Much Bounce – Use screwdriver and turn clockwise (to the right). Doing so will restrict pointer movement and reduce sensitivity.

Not Enough Movement – Use screwdriver and turn counter-clockwise (to the left). Doing so will loosen the dampener and allow for more movement.

With proper service and repair, your  Crown UMG will provide years of service. Proper service and repair, such as replacing worn seals, is important to the safe and reliable operation of all Crown equipment. The service procedures recommended by Crown and described above are recommended methods of performing service operations. Some of these service operations require the use of tools specifically designed for their purposes. These special tools should be used when and as recommended. For more information or for any questions, contact our friendly, knowledgeable staff at or at 1-877-908-3790. 

Like what you're reading? Sign Up for our newsletter and be the first to read our latest blog posts.