How to Repair Jalousie Windows: A Full Guide

Jalousie windows use a crank or lever to tilt a series of horizontal glass slats in unison, letting you control airflow precisely. Over time, the crank mechanism strips, the glass slats crack, or the vinyl clips that hold the glass wear out. This guide walks you through diagnosing the problem, replacing broken parts, and getting the window operating smoothly again—no special tools beyond a screwdriver and a tape measure.

What You’ll Need

Phillips and flathead screwdrivers (including a stubby one)
Replacement glass slats (measure the width and thickness first)
Replacement vinyl or metal clips (check the style before ordering)
Replacement crank handle or worm gear assembly (if the mechanism is stripped)
Silicone spray lubricant or white lithium grease
Pliers (needle-nose and standard)
Razor blade or utility knife
Clean rag and mild glass cleaner
Safety glasses and work gloves

Step-by-Step

Inspect the window fully. Crank it open and closed a few times. Note which slats are cracked, which clips are missing or broken, and whether the crank feels loose or slips. Look at the track ends—if the metal track is bent, the slats won’t move evenly.
Remove the broken glass slat. Crank the window so the broken slat is tilted nearly vertical. Gently push the slat to one side to slide it out of the track. If it’s stuck, use a flathead screwdriver to pry the end clips away from the track. Wear gloves—the edges are sharp.
Measure the slat. Use a tape measure to get the exact width (the long side) and thickness. Jalousie glass comes in standard widths like 3/16″ or 1/4″. Write these numbers down; you’ll need them for replacements.
Remove the remaining clips from the track. The clips are usually small plastic or metal pieces that snap into the track and hold the glass. Slide a flathead screwdriver under the clip and pop it out. Keep one intact clip as a sample for matching the replacement style.
Install the new clips. Slide the new clips into the track at the same spacing as the old ones—typically one at each end and one in the middle for long slats. Press them firmly until they snap into place.
Insert the new glass slat. Tilt the new slat at an angle and slide it into the track, then lower it into the clips. Make sure it sits evenly—check that both ends are at the same height. If it’s tight, apply a little silicone spray to the track first.
Test the crank. Turn the crank slowly. The new slat should move in sync with the others. If it lags or catches, adjust the clips—sometimes they need to be nudged a millimeter or two.
Repair the crank mechanism if needed. If the crank handle spins without moving the slats, the worm gear is stripped. Remove the handle by unscrewing the set screw, then remove the cover plate (usually 2-4 screws). Pull out the old gear assembly and replace it with a matching unit. Apply a thin layer of lithium grease to the new gear teeth before installing.
Lubricate the tracks. With the window fully closed, spray a small amount of silicone lubricant along both vertical tracks. Crank open and closed a few times to distribute it. Wipe off any excess with a rag.
Clean the glass. Use a mild glass cleaner and a lint-free cloth. Avoid ammonia-based cleaners if the slats have a tinted film—it can degrade the coating.
Final check. Crank the window fully open and fully closed. Confirm all slats close tightly with no gaps. If any slat doesn’t seat flush, adjust its clips or check for debris in the track.

Common Mistakes

Buying the wrong size glass. Jalousie slats are not universal. Even a 1/16″ difference in width means the slat won’t seat correctly. Always measure the old slat, not the track opening.
Forcing the slat into the track. If it doesn’t slide in easily, you’re either at the wrong angle or the track is bent. Forcing it will crack the new glass.
Using the wrong clips. There are at least a dozen clip styles. A clip that’s too small won’t hold the glass; one that’s too large will prevent the slat from tilting. Match the shape, not just the size.
Over-lubricating. Too much grease attracts dust and grit, which accelerates wear on the gear. A thin film is enough.
Ignoring a bent track. If the track is dented or bowed, new slats will still bind. You need to straighten the track or replace the whole window unit.

Tips

Take a photo of the window before disassembly. It’s easy to forget which clip goes where.
When ordering replacement glass, buy one extra slat. They’re fragile and it’s cheaper than a second shipping charge.
If the crank is stiff, check the pivot pins at the top and bottom of the slat stack—they often need a drop of oil.
For older windows, consider replacing all the clips at once, even if only one is broken. The others are likely the same age and will fail soon.
Work on a warm day. Cold plastic clips become brittle and snap more easily.
If the window is in a second-story room, remove the slats from inside. Never lean out to access them.

Troubleshooting

The crank turns but the slats don’t move. The worm gear is stripped. Replace the entire crank assembly—the gear and handle are typically sold as a unit. If the handle itself is loose, tighten the set screw first.
The slats move unevenly. One or more clips are worn or the track is dirty. Remove all slats, clean the track with a rag and mild solvent, then reinstall with fresh clips.
A slat won’t stay closed. The clips are too small or the glass is slightly warped. Check that the clip’s grip surface is contacting the full thickness of the glass. If not, get a thicker clip.
The window leaks air when closed. The slats may not be seating flush. Look for a bent slat or a clip that’s holding the glass at an angle. Also check the weatherstripping along the bottom rail—it may need replacing.
The crank handle is hard to turn. The gear needs lubrication, or the track has debris. Spray silicone into the track and apply grease to the gear. If it’s still stiff, the gear may be misaligned—loosen the mounting screws, reposition, and retighten.
Glass cracked during installation. The track was likely too narrow or the glass was twisted. Remove the pieces carefully, check the track width, and try again with a slightly thinner slat if needed.

Frequently Asked Questions

Can I replace just one glass slat? Yes, if the others are intact. Measure the old slat and order a matching replacement. Just be aware that a new slat may look slightly clearer than the older ones if they’ve yellowed with age.

How do I know which clip style I need? Remove one intact clip and compare it to photos online or bring it to a hardware store. The key dimensions are the width of the channel and the depth of the grip.

Are jalousie windows worth repairing, or should I replace the whole window? If the frame and track are in good shape, repairing slats and clips is cheap and easy. If the track is bent, the frame is rotted, or the mechanism fails repeatedly, a full replacement is more cost-effective.

Can I convert jalousie windows to regular casement windows? It’s possible but usually requires removing the entire frame and modifying the rough opening. That’s a significant project—consult a contractor for a quote before starting.

Why do jalousie windows leak so much? The slats can’t compress like a solid sash, so they rely on precise alignment and good weatherstripping. Over time, clips wear and slats warp, creating gaps. Regular maintenance—replacing clips and lubricating tracks—keeps them tighter.

What’s the best lubricant for jalousie windows? Dry silicone spray is ideal for the tracks because it doesn’t attract dust. For the gear mechanism, a small amount of white lithium grease works well. Avoid WD-40 as a long-term lubricant—it evaporates quickly.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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