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Simple Pump Maintenance - 100CA Cylinder Piston Seal

May 22, 2024
5 min read

Pump Cylinder Piston Seal Maintenance on the Simple Pump 100CA Pump Cylinder

Changing The Piston Seals on the 100CA Pump Cylinder

In order to replace the u-cup seals on the pump cylinder piston, the pump system must be pulled from the well as the piston is in the pump cylinder at the bottom of the pump system.

Remove the Piston from the Cylinder

Grab the piston rod and just pull it out.

The piston rod is threaded into the piston.

Change the piston seals.

All 100CA pump cylinder models prior to 2023 use two types of o-ring seals. They use two buna o-rings and two urethane o-rings. The urethane o-rings are on the outside top and bottom of the piston. The buna o-rings are the two middle seals on the piston.

Starting in 2023, we utilize four of the same style of seal and it's EP rubber, for durability, seal life, and easier maintenance.

Removing the Seals

  1. Using a sharp point tool or small flat tip screwdriver, get underneath the seal to pull the seal off of the piston.
  2. Don't worry If the seal is damaged getting it off the piston.
  3. Make sure the seal groove is clean and clear of debris before replacing the seals.

Replacing the Seals

  1. Once the old seals are off, start with the seal on the inside of the piston. If you have an older seal kit, this will be one of the buna o-rings. The seal u-cup needs to be pointed up towards the piston rod because it's going to spread when you're lifting the water and push it against the side of the cylinder.
  2. Get the o-ring just over the edge of the piston into the seal groove. The first couple of times you do this may be a little tricky. Get your tool underneath the o-ring and bring it around the piston to the middle groove.
  3. Continue replacing the remaining seals on the piston

Re-installing the Piston

  1. Once all of the seals have been replaced and are seated flat into the seal grooves we are ready to put our 100 piston and piston rod back in the 100 cylinder.
  2. Just like before when you just pulled it out to remove. You will just push it back into the cylinder to reinstall. NOTE: there are MPT threads in the top of the cylinder. They are fairly sharp, so you don't want to shove the piston in the cylinder. Gently push it in. As you push it down, you should hear the air pushing back up through the bottom of the piston.
  3. Once the piston is re-installed into the cylinder, the the pump system can be reinstalled into your well.