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How to Fix Window Locks: Possible Issues & Solutions

How to Fix Window Locks
Written by Willie F Brodson
Last Update: September 28, 2022

Window locks are essential for home security and if they are broken or not functioning as they should, the security of your whole family is jeopardized.

Here we will show you how to fix different types of window locks that any home-based DIYer can do if guided right.

How to Fix Different Types of Window Locks

  • Fixing the sash lock on a double-hung vinyl window

Things you need

  • A flat head screwdriver


1. Raise the lower sash and find the small “u” shaped fallen slot

You’ll find the slot (pivot block) at the footing of one side of your window track. This interferes with your ability to lock the window and allows you to raise and lower your sashes properly.

2. Raise the slot and make it aligned with the slot on the other side of the sash.

Stick your flat-head screwdriver in the fallen slot and turn it to 90°. You need to keep the screwdriver in the slot the entire time since it’ll have a high spring tension on it. Turn the screwdriver until the slot is horizontal.

You’ll feel the slot wanting to go up immediately as you turn it horizontally, but hold on to the screwdriver and let it rise gently. When it’s about 5-6 inches raised from the window track, turn the slot vertical again. Make sure it’s facing up like a “U”.

3. Lower the bottom sash and see if the pivot bar inside engages fully

If the pivot bar inside engages all the way when you push the bottom sash down, go to the next step. If not, then you’ll need to adjust the slots once more.

4. Tilt the lower sash out and make sure it’s completely in and then try to lock it

The task is successfully done if you can lock your window now. Go for a replacement in case you notice that the locking mechanism in the window is completely broken.

Note: If you can’t lock your double-hung window or feel excessive resistance as you try to engage the lock, a possible explanation could be the improperly closed sashes. Push the top sash up and the bottom sash down. This will help ensure the lock will fit the keeper and engage.

  • Fixing a locked casement window that has a broken lock lever

Things you need

  • Scraper knife
  • Regular hammer
  • Phillips screwdriver


1. Insert your scraper knife into the window frame

Carefully push the scraper knife into the frame as deep as you can without damaging the rubber and slide downward until it hits the hidden metal linkage inside.

2. Hammer downward until the linkage is fallen off

Grab that hammer and lightly tap it onto the side of the knife. Soon you’ll see the window is released.

3. Reconnect the broken lever to the linkage that just fallen off

Reconnect the broken lever

Go ahead and unhook the link arm attachment with a push of your finger. Take the 2 screws out using your Phillips screwdriver and slide out the lock from the window frame.

4. Put the parts back together

Put the parts back together

Be sure to put the split arm on the right way to avoid issues ahead. Replace the washer if it looks unusable.

5. Reinstall the latch

Reinstall the latch

Re-engage the rod on the side without dropping the screws and drive the 2 screws in. Now you should be able to lock and unlock the window easily.

Note: If your casement window locks have no interior facing screws and the locking lever has broken off in the locked position, you can easily open it with a slender tool like a thin screwdriver. Push the tool inside the lock hole and try to drag down the mechanism until your lock is disengaged. Remove and replace the damaged lock with a new one.

  • Fixing a blocked window handle


  1. Turn open the sash and locate the metal levers on the side.
  2. Push the metal lever and turn the window handle at the same time.
  3. Close the window and check it.
  • Opening a locked window using paper clips

Things you need

  • 2 ordinary metal paper clips


  1.  Make a tensioning tool with one paper clip. Open up one paper clip as straight as possible and bend the two points toward each other. Squash the loop together with a pair of pliers. Then bend over the flattened end about ½” to one side.
  2. Take the other paper clip and open up just one side of it with a bit of an angle.
  3. Take the tensioning tool and put it in the top of the keyway with one hand.  Keep it as high up as possible so you have maximum clearance to pick the pins inside. Try to bump all of the pins down using the paper clip prickle with the other hand.

Once you’ve got the pins down, take off a little bit of tension as you wait for the clicking sounds. Make sure you don’t overset it at this point. Turn the keyway over entirely to the side and get your window unlocked.

  • Fixing an old wood window’s lock with a SAG in the check rail

Things you need

  1. Leatherman tool
  2. Phillips and Flathead screwdriver
  3. Wood toothpicks
  4. Sash lock shims (1/16” or 1/8”)
  5. Long screws (3”)


  1. Start with the 1/8” shims and stack them up next to the lock to get a level space for your keep and lock to line up nice and tight. You may need 2-3 shims per lock. Set the lift or catch to test it out.
  2. Stick the toothpicks in there if the holes on the window sill are quite opened up and break off the excess.
  3. Set the shims on top of the screw holes, get everything lined up, and drive the screws. Make sure the lock fits the keep perfectly. And do not use a power tool for this task.
  • Fixing a window that has a loose handle or spindle detached

Fixing a window that has a loose handle

Things you need

  • A pair of Tweezers
  • Screwdrivers


  1. Remove the 2 screws holding the handle if the handle isn’t linked with the metal attachment inside and pull the handle off carefully.
  2. You’ll see the metal attachment that drives the locking mechanism inside. Pull it out with tweezers.
  3. Once the metal piece is out, you need to secure the piece back into the handle and lightly hammer it a couple of times to make sure it stays in position.
  4. Reinstall the handle back into the sash and screw it back on to reconnect the handle and the locking mechanism of your window.
  • Fixing sticking double glazed windows and locks with WD-40

Things you need for this job

  1. Good quality PDF sprayer (preferably WD-40)
  2. Cleaning brush


  1. Clean the dirt on the edges of your window with a brush.
  2. Grab the can, give it a shake, and apply the formula to your window’s closing and locking mechanism. It’ll allow you to get rid of the stiffness and make your window operate a lot more smoothly.


1. How do I fix a window frame gap?

Ans: Apply gap fillers like Selleys “No More Gaps”. They are flexible and have low shrinkage. You may use them to fill gaps and resist cracking. Clean and dry the area you’re going to apply the gap filler. Read the instructions on the cartridge to apply the filler the best way.

2. How much does it cost to fix a broken window?

Ans: Replacing a broken window glass can cost you between $200-and $500 on average. You may expect to spend a lot more depending on the kind of repair you need, the size of your window, and the type of material you go for. It’s around $2,000 including the labor costs in many cases.

About the author

Willie F Brodson

Certified by the Board of Certified Safety Professionals and a master of Science in Occupational Safety Management from Indiana State University, Willie F Brodson is an occupational safety expert who believes in the age-old saying – “It is better to be safe than sorry.”

Willie’s areas of expertise include legal guidelines for health and safety, coding and construction safety, fire prevention and theft, and environmental technology. Over a span of four decades, he has provided safety training and consultation and developed safety manuals for a number of state-owned and private organizations.

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