How to Replace Seals on 4:1 Debooster

Posted on Oct 04, 2018 by Kathy DeGlandon

The 1502 4:1 gauge protector debooster (CWDB4X) is fitted with seals that assist the gauge protector in sensing and transmitting pressure to a hydraulic pressure gauge. When the seals becomes worn or damaged they will need to be replaced.  Using a replacement seal kit (CKT204-1), follow these steps to replace the seals in your CWDB4X 1502 gauge protector debooster.


What You'll Need:

  • Hex Cross (CJ100-1)
  • Plug with Teflon Tape
  • Check Valve (CC102)
  • Seal Kit (CKT204-1)
  • Debooster
  • Williams Adjustable Spanner Wrench
  • One Inch Socket
  • 5/8" Wrench

Step 1.   Attach lower sub of debooster to vice. Using a 5/8” wrench, remove the brass plug from the hex cross at the top of the debooster cap.

Step 2. Using a 5/8” crescent wrench, remove the check valve from hex cross at the top of the debooster cap.

Step 3. Using a 1” socket, remove the hex cross at the top of the debooster cap.

Step 4. Using a Williams adjustable spanner wrench, remove the debooster cap. Spanner wrench fits in debooster cap hole as shown.

Step 5. Remove the debooster from the vice. Turn the debooster right-side up, and remove 1502 hammer union for debooster housing by lifting the wing nut over the housing until it is free of the housing. Hammer union will only slide one way, over the top of the housing, not the bottom.

Step 6. Because the seals are located on the piston, the piston will need to be removed from the

housing. With the wing nut removed, turn the housing on its side to reveal the bottom

of the housing and piston. Using your index finger or a small, rounded backend of screw- driver, push the piston up until it can be removed from the top of the housing.

Step 7. Once the piston is removed from the housing, remove old, worn T-seals and O-ring with dental pick or a small, pointed tool that will release them from the designated groove. With old seals removed, place small O-ring on bottom of piston in O-ring  groove, then add one T-Seal above and below the O-ring.

Step 8. Turn the piston over to the top, larger side. Place large O-ring seal on top of the piston in designated groove, then add one T-Seal above and below the O-ring.

Step 9. Using a silicon-based grease, brush  grease on inside of housing and on upper and lower seals. Grease is important to movement of piston and to keep seals intact during installation. Failure to add grease could result in seals being crimped or torn and/or piston seizing or freezing in place.

Step 10. With new seals in place, slide smaller side of piston into debooster housing.  Piston should be pushed into the housing until it fits just below flush with the housing top. Piston will be flush with the bottom of the housing and in the “down” position prior to pumping debooster up with fluid.

Step 11. Place last seal on top of piston in housing.  Using extra grease that is on the top of the housing and piston, cover seal with grease. Doing to will protect the seal when the debooster cap is replaced. Notice the piston is in the “down” position and just below flush of the debooster housing.

Step 12. Replace hammer union.

Step 13. Replace debooster cap until finger tight. Use Williams spanner wrench to tighten.  Do not over tighten.

Step 14. Using 1” socket, replace hex cross on top of debooster cap.  Do not over tighten.

Step 15. Using a 5/8” wrench, replace the check valve on the side of the hex cross at the top of the debooster cap. Do not overtighten.

Step 16. Using a 5/8”  wrench, replace the brass plug onto top of hex cross at the top of the debooster cap. Do not overtighten.

Important Safety Notice

Proper service and repair is important to the safe and reliable operation of all Crown Oilfield Instrumentation equipment. The service procedures recommended by Crown Oilfield Instrumentation and described in the service guide are recommended methods of performing service operations. Some of these service operations require the use of tools specially designed for their purposes. These special tools should be used when and as recommended.


It is important to note that some warnings against the use of specific service methods stated in the guide can damage the equipment or render them unsafe. It is also important to understand these warnings are not exclusive. Crown Oilfield Instrumentation could not possibly know, evaluate and advise service personnel of all conceivable methods in which service might be done or of the possible hazardous consequences which may occur. Accordingly, anyone who uses service procedures or tools, which are not recommended by Crown Oilfield Instrumentation, must first thoroughly satisfy himself that neither his safety nor equipment safety will be jeopardized by the method selected.


For additional assistance, please contact our friendly, knowledgeable staff at 1-877-908-3790.