Repair Failed Window Counterbalance

A lot of modern tilt-in windows have spring-loaded counterbalances that are attached to the window with small plastic clips called shoes. These shoes can fail after a few years, rendering the counterbalance inoperative. The fix is relatively simple once you know the technique.

• Safety glasses
• Flat screwdriver
• Gloves
• Replacement balance shoes

Balance shoes can be purchased online; try searching for "tilt window pivot shoes." We obtained ours directly from the window manufacturer by calling their customer support number.

We first need to get the window sash out of the frame. This is tricky because you have to support the full weight of the window while you tilt it in. I usually raise it 8 inches or so, and then tilt it in 90 degrees (so it's lying flat). At this point you can lift one corner straight up and out of the balance shoe; once that corner comes out, lift the other corner out of the shoe and the sash will be completely free from the frame. Carefully place the sash somewhere safe while you continue the repair.

The balance shoe is designed to lock its position in the frame when you tilt the window sash, for example for cleaning. It locks this way so that the sash won't move up and down while tilted. The secret to the locking and unlocking is a cylindrical metal cam with a U-shaped slot in the end (see the pictures).

This cam rotates when the sash is tilted, and the position determines whether or not it's locked:

• When the U-shaped opening is pointing up, the shoe is locked and won't slide up or down. It will be in this position when the window sash is tilted horizontal.
• When the opening is rotated 90 degrees, the shoe is unlocked and can slide up and down. This is the normal operating mode of the window, when the sash is tilted vertical.

Since we're going to be replacing these balance shoes, we will need to manually set the cam position (locked or unlocked) using a flat screwdriver.

When you removed the window sash, the old balance shoes were left in locked mode. We will need to unlock them before removing them from the frame. They are locked when the U-shaped opening in the cam is pointed up, so unlock them with your flat screwdriver by rotating the cam 90 degrees. Once it's unlocked, you can tilt the shoe out of the track and twist to remove it as shown in the video.

This is the trickiest part. Make sure the replacement shoe is in unlocked mode and insert it into the track using these steps, and using the video as a guide.

• insert the shoe sideways into the track
• turn it 90 degrees to engage it into the track. Make sure the cam is on the bottom (pointing down)
• at this point the "hook" part of the shoe will be pointing up toward the window balance
• grab the window balance and pull it down. You'll have to pull pretty hard
• there is a metal bar inside the balance, near the end. The idea here is to engage this bar into the hook in the shoe
• while holding the balance with one hand, push the shoe hook up into the end of the balance. The hook should engage the metal bar in the balance
• now push the balance (horizontally) all the way into the window track. The shoe should stay connected as it goes
• you should hear a click or snap when the shoe fully engages into the balance

That's it. You can now let the balance go (slowly) back up to the top of the track.

With the balance shoes unlocked, pull each counterbalance down about 12 inches. You'll have to pull pretty hard. Then, while holding them in place with one hand, lock the balance shoe by turning the cam with your flat screwdriver. The U shaped opening in the cam should be pointing up as you can see in the video.

Now all that's left to do is reinstall the window sash by reversing the removal steps. The sash has a rectangular post on each bottom corner; these posts slot into the U shaped openings in the balance shoes. Hold the window in place and carefully drop one corner post into one balance shoe, and then drop the other one in. Once both posts are in the balance shoes, you can tilt the window up into place. The repair is now finished and the counterbalances will function as new.

Here's a failed shoe next to a brand new one. It's clear what the failure was - the plastic clip broke. It seems they could make these metal if they wanted to.