How do I change the springs in a medium PlexiDor dog door?

Spring in the PlexiDor frameThe medium PlexiDor dog door has saloon-style panels, and there is a spring on each side. 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
  • 3/8 inch nut driver
  • 5/16 nut driver
  • Phillips head screwdriver
  • Flat head screwdriver

To be able to access the springs, you need to remove the pet door’s interior frame from the door or wall. Unscrew the four retaining screws and slid it out of the mounting hole.

The springs are protected by a spring hood. Unscrew the hex head screws and lift the hood on each side over the rivet head.

If your door is manufactured before 2008, the new springs may be too tall to fit under the spring hood. The new springs should not touch the top of the spring hood. If this happens, just leave the spring hood off.

Spring hoods on a PlexiDor dog door

The next step is removing the pivot screw that holds the bent arm in position. Use a 5/16 nut driver. Remove the old bent arm and spring.

Spring in a Medium Plexidor

Putting everything back together will be easier if you take a moment to clean the frame. You can use warm water with Dawn to wipe it down. This will also ensure you don’t get old dirt in the new spring assembly.

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

  • Push the new pivot pin into the frame. The notched end should go on top.
  • Put the gray nylon shoulder washer over the pivot pin. The wide part should go on top.
  • The nylon tube spacer goes over the pivot pin.
  • Put on the dark gray nylon 0.092 thrust washer.
  • Next, put on an opaque white flat nylon washer
  • Put the spring on the 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.

  • Snap the bent arm onto the pivot pin
  • Place the internal tooth washer on top of the bent arm and slide screw down into the pivot pin
  • Hold the pet door panel in the center of the frame and tighten the pivot pin screw. It should be snug, but not overtigthened.

Repeat for the other side.

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 panels are fully opened.

The parts come together in this order:

PlexiDor medium spring assembly

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 shows the procedure step-by-step.