If your hot tub has developed a leak between the pump and pump motor, then it is likely that the pump's wet-end seal has failed. Fortunately, replacement isn't difficult, and it can be accomplished by most spa owners with a minimum of tools and time. Below is what you need and how to perform the replacement:
Tools and materials needed
Replacement wet-end seal for your particular spa
1-inch PVC slip coupling
Tube of silicone sealant
How to replace the seal
1. Open the pump housing—After you have removed the pump from the spa, the first step to replacing the wet-end seal is to take off the pump's cover. Depending on the specific model you own, the cover might be attached with several Phillips-head screws. Remove the screws and set them aside in a safe location, then lift the cover from the pump housing; use a flat-head screwdriver to gently pry the cover if it doesn't pop off readily.
2. Remove the pump's internal components—Once you have access to the inside of the pump, the internal parts should be accessible and easy to remove. First, lift up the spacer that holds the impeller to the pump cover, then remove the impeller itself. While you have the impeller out of the pump, take a quick look to be sure it hasn't been damaged by any waterborne debris. Finally, take out the bearing or bushing if it isn't integrated with the impeller.
3. Remove the wet-end seal—With all of the internal parts out of the way, the wet-end seal will be exposed. Turn the pump housing over and insert the tip of a flat-bladed screwdriver into the opening above the wet-end seal. Tap it lightly with a hammer to knock the seal out of the housing. Inspect the interior of the pump housing where the seal was mounted and remove any bits of silicone or other debris that might be present.
4. Install the new wet-end seal—Once the old seal is out of the way and its mounting location is clean, test fit the new seal to be sure it will seat correctly. Next, apply a thin line of silicone sealant around the circumference of the seal, then slide it into position in the housing. Place a 1-inch PVC slip coupling on top of the seal, then lightly tap it with a hammer to ensure the seal is firmly mounted and in place.
5. Rebuild the pump—When the new seal has been installed, replace the pump's internal components in reverse order from how they were removed. Place the cover on top of the housing, then reinsert the screws; be sure to fasten the screws in a "crisscross" pattern so you apply even pressure to the cover and create a watertight seal with the housing.
If you run into any trouble or would prefer to have the wet-end seal replaced by a professional, contact a service like Anchor Pools & Spas.