How do I change the spring in a small PlexiDor?

The small PlexiDor intended for cats and small dogs has a single panel and only one spring. Changing it is easy and the spring replacement kit contains these step-by-step instructions.

Besides the spring kit, you will need:

• Small wire grip pliers
• 5/16 nut driver
• Flat head screwdriver

Start with removing the interior frame of the pet door from its installation site through unscrewing the four retaining screws and sliding it out of the mounting hole.

Remove the spring hood by unscrewing the hex head screw and lifting the hood off.

Now when you can access the spring, remove the pivot screw that holds the bent arm. You will need a 5/16 nut driver. Remove the old bent arm and spring.

This is a good time to clean the pet door frame, to make sure you don’t get old grime in the new spring. You can for instance wipe it down with warm water and Dawn.

Once all the parts of the old spring have been removed:

• Push a new white tube spacer into the frame.
• Put the white thruster washer over the tube spacer and push it down to the frame
• Put the white flat washer over the tube spacer
• Put the spring on top of the nylon tube

One side of the spring has a tail that points up slightly. This part should be on the bottom. Take a pair of small wire gripping pliers, grab the top spring end, and wind around and hook it over the vertical plate.

• Put on the external tooth washer
• Snap the bent arm onto the pivot pin screw
• Place the internal tooth washer on top of the bent arm, and slide the pivot pin screw down through the spring assembly, into the pet door frame

Next you need to lock the pet door. Hold the pet door panel in the center of the frame and tighten the pivot pin screw.

Do not over-tighten – it should be snug, but not hard. Make sure the panel stays in place and centered as you tighten the screw.

You may need to trim the spring tail ends so they extend about 1/16″ beyond the vertical plate. Check that the spring tails don’t touch anything and hinder the door’s operation when the door is fully opened.

The parts come together in this order:

When you have made sure the spring is installed right – the door works as it should – apply a high quality grease to the spring. We use marine grease for longevity.

Do not use WD40 as grease – it’s a cleaner.

Replace the spring hood – don’t over-tighten the hood mount screws – and slide the pet door back into its mounting hole.

The following video isn’t specifically for the small PlexiDor, but the principle is the same: