I'm the building manager and handyman for our block of units, built in 1972. Most of the windows are aluminium framed glass that slide on little plastic wheels along the integrated track. Over time, in our case nearly 50 years, dirt build-up and wear can cause the wheels to seize up. Not only does this make the window hard to open and close, if the faulty wheels are not replaced the scraping motion of metal-on-metal can wear away the track to the point the window stops opening or worse falls out entirely!

This Instructable shows you an easy way to repair this issue at a fraction of the cost of replacing the window that should last for years to come.

Tutorial Video: The Video above on my YouTube Channel will be a good visual companion to this Ible. Make sure you check it out.

Supplies

Materials:

Replacement Window Roller Wheels - These will be specific to your model of window. The best thing to do is take out one of the old ones and bring it to the hardware store or a window supplier to match them if you can't find the correct ones online. Here is an example of what they should look like.
Replacement Window Track - This stuff is not super cheap, but compared to replacing the widow good value! The Window Track comes in a variety of lengths so measure up your window and get the closest length to the one you need.
- USA - Prime-Line Sliding Repair Track
- Australia - "Miracle Track" from Bunnings
Small Tube of Clear Silicone

Tools:

Tape Measure
Screw Drivers
A Metal File
A Hack Saw
A Dust Pan
Optional - Clamps
Optional - Caulking Gun (if you don't get the squeezy tube)
Optional - Shop Vac

(NB: The links above will take you to Amazon.com where you can source some of the gear I use if you can't find it locally. It won't cost you any more than normal Amazon, but purchasing via that link gives me a small commission and supports my work. Thanks!)

Step 1: Remove the Window for Inspection

Most of these styles of sliding windows lift out. Be careful as they can be quite heavy, get help if you need it. If it won't lift out, check for little locking lugs on either side at the top that should unscrew and then allow you to simply lift and pull.

There are two parts you will need to check. Carefully flip the window upside down and take a look at the little nylon plastic wheels. If your window has not been sliding well chances are they are gunked up or broken. If that is the case, we'll replace those in the next steps.

Then take a peek at the actual metal track in the window sill. I can guarantee it is probably filthy (don't worry, everyone's are! :P) but more importantly, check for "flat spots" and damage. Compare the track near the wall (where the window rarely rolls) to the track near the middle. If there is significant wear and tear the second half of this Ible will show you how to fix that.

Step 2: Replacing the Window Wheels

These nylon or plastic wheels that allow the window to roll open and closed are not very expensive and super easy to replace. The hardest part may be finding the correct sized ones. Note that there is usually a LEFT and a RIGHT wheel that will be mirrors of each other and go at either end of the window.

Prime-Line is a company that sells on Amazon various styles and are worth checking out. Otherwise, pull an old one out, take it to your local hardware or window supplier and they should be able to match it.

TIP: Sometimes you can find spare wheels attached to the TOP of the windows. Have a quick look!

Unscrew the old wheels and use a flat head screwdriver then lever them out. (Don't dispose of the old screw until you've checked the new ones have the correct thread.)
Thoroughly clean the bottom of the window with a brush.
Install the new wheels noting the Left and Right orientations.

Easy as that! If your track is in good condition you can simply clean the track sill, reinstall the window and you're done. But we are assuming here the track is damaged. If this is the case don't run your new wheels on a damaged track or you risk the sharp edges of the aluminium cutting the new plastic wheels and ruining them instantly.

Step 3: Prepare the New Window Track

Now we can prepare to install the new Window Track.

Grab a brush and a vacuum and give the whole track area a good clean.
Measure out the old track. It's fine if your new track is a little shorter, in fact being an inch (25mm) shy will make installation easier.
Transfer your measurement to the new section of track.
Use a hacksaw to cut the track to length. These tracks are stainless steel and quite tough so this may take a little effort. If you have a clamp or a vice to hold the track still this will be much easier.
Use a file to clean up the edges of your cut.

With that, we are ready to install.

Step 4: Install the New Window Track

Installation is also very straightforward. The hardest part is lining things up.

Grab your silicone in either a tube or caulk gun and run a thin bead the entire length of the underside of the new track. Start and stop about an inch (25mm) from either end so you don't get squeeze out.
This is the tricky bit! Grab your track and being careful not to bend it, hook one end over the old damage track. Slowly lower the new track gently pressing down as you go until the entire length covers the old track. Once down, ensure the gap at either end is even (about 12mm or 1/2")

TIP: If the old track is very bent or flattened, grab a hammer and a thin block of wood. Place the thin block over the trouble section and gently tap with the hammer to knock the new track into position. The new steel track is stronger than the aluminium, so it will give way.

Pick up your window and gently lift it into position. Run it slowly backwards and forwards along the whole length of the new track. Not only will this test you've installed everything correctly, but the weight of the window will fully seat the new track too.
Leave the window half-open (sitting in the middle of the track) until the silicone cures.

Step 5: Enjoy Smooth Sliding Window Operation

You did it! Clean up the mess, put on the kettle and relax. That pesky stuck sliding window shouldn't give you any more grief for a number of years, especially if you stay in the habit of the odd vacuum clean and at the first sign of the wheels becoming stiff, lifting it off for a look before they can damage your new track.

If you have any questions, need clarification or spot an error, please don't hesitate to contact me.

I release regular woodwork and DIY content on my YouTube Channel - Fixit Fingers including lots of content for beginners. I'd love to have you come check it out and join me.

I have a curated list of handyman and tools and supplies on my Amazon Store for your browsing pleasure too.

Otherwise, you can see what I'm up to in between videos on my Instagram @FixitFingers and Fixit Fingers on Facebook.

Cheers! James