If your dishwasher is overflowing or leaking from the front, it probably has a defective drain pump. The drain pump is responsible for pushing the water out of the bottom of the dishwasher and into the drain hose that connects to your kitchen sink. When shopping for a replacement drain pump, take the part number from your owner's manual or use the old pump as an example to make sure you get the right part for your particular make and model of dishwasher.
Turn off the circuit breaker switch that controls power to the kitchen before you begin working on the dishwasher. If you are replacing the drain pump on a portable dishwasher, you may be able to unplug the power cord instead of flipping the breaker switch.
Remove the bottom dish rack from the inside the dishwasher. Use the end of a flathead screwdriver to pry off the cap on top of the spray arm bolt. Some dishwashers may not have this cap and the bolt will already be exposed. Remove the bolt with a socket wrench and lift the spray arm off the spindle.
Block the blades of the impeller at the bottom of the dishwasher with a stick or plastic fork. Remove the screws that hold the impeller onto the dishwasher unit. Lift the impeller out and set it aside.
Move to the front of the unit and remove the screws that connect the bottom panel and kick panel to the rest of the dishwasher. Take off the panels and set them aside.
Find the hose that runs from the drain pump at the bottom of the dishwasher to the kitchen sink. Set a rag under the point where the hose connects to the pump. Loosen the screw on the hose clamp to disconnect the drain hose from the pump. Move back to the inside of the dishwasher and lift the drain pump up and out to remove it.
Insert the replacement drain pump into the bottom of the dishwasher. Move to the front of the dishwasher and attach the drain hose to the pump. Tighten the screw on the hose clamp to secure the drain hose. Replace the kick panel and bottom panel and tighten the screws.
Return the impeller to its place inside the dishwasher cabinet. Tighten the mounting screws and remove the stick or fork you used to block the blades in Step 3. Set the spray arm back on top of the spindle and tighten the bolt. Replace the plastic cap, if applicable to your dishwasher.
Replace the bottom dish rack and turn on the breaker switch to restore power to the dishwasher. Run a test cycle with no dishes in the racks to make sure your new drain pump is working properly.