The S152 Series screw-in constant-force balance uses one or more stainless-steel coil springs, a pivot lock shoe, and a protective balance cover to support the sash in a tilt window.

Safety Warning: Constant-force coils contain stored spring tension and may have sharp metal edges. Wear eye and hand protection, keep each coil controlled, and do not allow a spring to unwind suddenly.

Do not bend, flatten, cut, or unroll the coil. Stop if the assembly, mounting method, or original coil arrangement is unclear.

Constant-force balance components that appear similar may differ in coil width, spring rating, shoe dimensions, cam style, housing shape, and mounting-hole location.

Compare the replacement with the original and record:

• The stamp or weight rating on each coil
• The number of coils used on each side
• Single, tandem, or triple configuration
• The order in which multiple coils are stacked
• Coil width and attachment-hole position
• Pivot lock shoe dimensions and profile
• Metal cam shape and orientation
• Balance-cover style and mounting location
• Original screw sizes and positions

The left and right balance assemblies should use matching configurations and provide the correct combined support for the sash.

Arrange the coil springs in the same order and direction as the original balance.

1. Place the lower coil in position beside the pivot lock shoe.
2. For a tandem or triple assembly, position the next coil above it.
3. Line up the attachment holes in the stacked coils.
4. Confirm that the coils face the same direction as the original assembly.

The outer end of the upper coil may need to be moved outward slightly so the attachment holes remain aligned. Do not crease or sharply bend the spring.

Position the aligned coil holes over the attachment hole in the pivot lock shoe.

1. Keep the coil stack controlled with one hand.
2. Align the coil holes with the screw opening in the shoe.
3. Insert the retaining screw far enough to hold the coils in position.
4. Confirm that no coil has shifted or twisted.

The screw should pass through the complete coil stack and engage the intended attachment point in the shoe.

Tighten the retaining screw through the pivot lock shoe to secure the coil springs.

For the assembly shown in the original WHD instructions, the recommended screw is a #6 screw approximately 1/2 to 3/4 inch long. Confirm the correct length for the actual shoe and number of coils being assembled.

Tighten the screw securely without stripping the shoe or crushing the coil stack. The coils should remain aligned and able to roll into their normal operating position.

Position the balance cover or housing around the coil springs in the same orientation as the original assembly.

1. Keep the coils rolled and controlled.
2. Fit the cover around the outside of the coil stack.
3. Confirm that each coil is seated within the cover.
4. Align the front mounting hole with the original installation direction.
5. Make sure the shoe can move beneath the assembled balance.

The housing should contain and guide the coils without pinching their edges or forcing them out of alignment.

Insert the completed balance assembly into the same jamb pocket or mounting position used by the original balance.

1. Orient the cover, coils, and pivot lock shoe correctly.
2. Place the shoe into the jamb track.
3. Position the balance cover against the original mounting surface.
4. Make sure the shoe can travel vertically without binding.
5. Confirm that the assembly is not reversed or twisted.

Insert the mounting screw through the hole in the front of the balance cover and secure the assembly at the original jamb location.

1. Align the cover with the original mounting hole.
2. Install the correct screw through the cover.
3. Tighten the screw until the assembly is secure.
4. Do not overtighten the screw in vinyl or weakened jamb material.
5. Confirm that the cover sits flat and does not interfere with the sash.

Repeat the assembly and mounting procedure for the balance on the opposite side of the window.

Use a flat-head screwdriver to control and position each pivot lock shoe.

1. Insert the screwdriver securely into the metal cam.
2. Rotate the cam to unlock the shoe while maintaining control.
3. Pull the shoe downward approximately 6 to 8 inches.
4. Rotate the cam back into the locked position.
5. Repeat on the opposite side.

Position the left and right shoes at approximately the same height before reinstalling the sash.

One shoe may be placed slightly higher temporarily to make seating the two pivot bars easier.

1. Hold the sash nearly horizontal with the top tilted toward you.
2. Insert the first sash pivot bar into the cam of one pivot lock shoe.
3. Angle the sash slightly and insert the opposite pivot bar.
4. Confirm that both pivot bars are fully seated.
5. Level the sash before tilting it upward.
6. Raise the sash into the frame until both tilt latches engage.
7. Lower the sash gently.

Do not force the pivot bars into the shoes. Recheck the shoe height, cam position, and pivot-bar alignment if either side will not seat correctly.

Raise and lower the sash slowly several times after installation.

Confirm that the sash:

• Moves smoothly and evenly
• Remains open at several positions
• Does not drift downward or rise on its own
• Does not bind against either jamb
• Remains level while moving
• Closes completely
• Locks correctly
• Remains securely connected to both pivot shoes

A worn coil may not be the only damaged component. Inspect the complete balance and sash-support system.

• Cracked or distorted pivot lock shoes
• Worn or damaged metal cams
• Bent, loose, or broken sash pivot bars
• Torn, stretched, separated, or corroded coils
• Cracked or damaged balance covers
• Loose retaining or mounting screws
• Damaged jamb tracks
• Cracked sash corners
• Uneven wear between the left and right assemblies

• Installing coils with the wrong weight rating
• Changing the original number or stacking order of the coils
• Reversing the direction of a coil
• Creasing, flattening, or unrolling the spring
• Using an oversized retaining screw
• Failing to pass the screw through every coil in the stack
• Pinching a coil inside the balance cover
• Mounting the cover in the wrong location or orientation
• Unlocking the shoe without controlling it
• Positioning the two shoes at significantly different heights
• Allowing the sash to hang from one pivot bar
• Forcing the pivot bars into the shoe cams
• Discarding the original hardware before testing the replacement

Assembling an S152 Series balance requires aligning the correct coil springs, securing them to the pivot lock shoe, fitting the cover around the coil stack, and mounting the completed assembly in its original jamb position.

Keep the springs and pivot shoes controlled throughout the process, position both shoes evenly, and test the sash slowly after installation.