How to Replace a Pool Cleaner Side Brush Axle

Why the side brush axle matters

The side brush on a robotic pool cleaner scrubs walls and waterline areas that the main brush cannot reach. The axle is the rod that holds the brush and lets it rotate around a fixed point. When the axle bends or breaks, the brush stops spinning or wobbles, and cleaning performance drops. If you notice streaks along the waterline or on vertical walls, a damaged axle is a common cause. For more on how side brushes work, see side brushes explained.

Side brushes are especially important for wall-climbing models, where they maintain contact with vertical surfaces. A stable axle keeps the brush perpendicular to the wall, ensuring even pressure. Without it, the brush may skip over areas or leave a distinct line of debris. Understanding the role of the axle helps you diagnose problems accurately.

Signs of a bent or broken axle

Common signs of a bent or broken axle include: a brush that does not rotate, abnormal noise from the side brush area, visible wobble in the brush, and reduced cleaning effectiveness along edges. Sometimes the axle is simply out of alignment, but a visible bend or break requires replacement. If the brush is not spinning at all, check the axle before suspecting the motor.

You can also inspect the brush when the cleaner is off. Try to turn the brush by hand; it should spin freely with minimal resistance. If it binds or feels loose, the axle may be damaged. Regular inspection after each cleaning cycle helps you catch problems early.

• Brush does not rotate during operation
• Unusual grinding or clicking sound from the side area
• Brush appears tilted or wobbles when spinning
• Visible bend or crack on the axle itself

Prepare for the replacement

Before starting, unplug the cleaner from its power supply. Robotic cleaners use low voltage, but you should still disconnect to avoid any risk. Read the user manual for your specific model; the side brush assembly location and fasteners vary. Common tools include a Phillips screwdriver, a small flathead screwdriver, and sometimes a hex wrench.

Order the correct replacement axle from the manufacturer or an authorized parts distributor. Verify the part number matches your model. Refer to the replacement parts guide for advice on sourcing parts. Always follow safety practices when handling equipment, as outlined in pool cleaner safety tips.

Remove the side brush assembly

Turn the cleaner over so the bottom is accessible. Locate the side brush, which is typically mounted near the edge of the chassis. It is often secured by one or more screws through a hub. Remove the screws and gently pull the brush off the mounting hub. If the brush is stuck, use a flat screwdriver to pry it free, but avoid damaging the housing.

Once the brush is off, you can see the axle protruding from the gear or motor. Remove any retaining clip or screw that holds the axle in place. Keep all fasteners organized. Some models may require you to open the main housing; refer to your manual. For brush type information, see brush types.

Install the new axle

Inspect the new axle to make sure it matches the original in length and diameter. Apply a light coat of silicone lubricant to the shaft to ease installation and reduce friction. Insert the axle into the mounting hole and secure it with the original clip or screw. Make sure the axle spins freely without wobble.

Then attach the side brush onto the axle, aligning any notches or flats, and tighten the screws. Do not over-tighten, as that can strip threads. The brush should sit flush and rotate evenly when you spin it by hand. If there is any resistance, recheck the alignment.

Reassemble and test

Reassemble any parts you removed and place the cleaner back upright. Plug it in and run a short cycle in a small area. Watch the side brush turn; it should rotate smoothly and stay level. If you see wobble or hear grinding, stop and recheck the axle installation.

A properly installed brush will not leave gaps along walls and waterline. After the test, inspect the area to confirm the brush is scrubbing uniformly. If you notice any issue, consult the troubleshooting guide for further steps.

When to replace the whole assembly or cleaner

If the axle fails again soon after replacement, the brush assembly or the drive gear may be worn. In that case, consider replacing the entire side brush assembly rather than just the axle. If your cleaner is old and needs frequent repairs, it might be time to compare new models.

Explore our best robotic pool cleaners and best cordless robotic pool cleaners for upgrade options. If you use a specific brand like Dolphin or Aiper, their dedicated guides can help you choose a replacement or a new unit: best Dolphin pool cleaners and best AIPER pool cleaners.

What to pick for your use

Questions

How can I tell if the side brush axle is bent?

If the brush does not turn or rotates unevenly, or you see a gap between the brush and the wall, inspect the axle for a visible bend. Also, a wobble when spinning is a strong indicator.

What tools do I need to replace a side brush axle?

Typically a Phillips screwdriver, a small flathead screwdriver, and possibly a hex key. Check your manual for exact requirements, as some models use Torx or other fasteners.

Can I replace the side brush axle myself?

Yes, most robotic cleaner owners can do it with basic tools. Follow the manual and take care when disassembling. If you are unsure, contact the manufacturer's support.

What if the brush still does not turn after replacing the axle?

The issue could be the drive motor or a gear problem. Recheck the installation and consult the troubleshooting guide to isolate the cause.

How often should I check the side brush axle?

Inspect it monthly or whenever you notice reduced cleaning along walls and waterline. Catching a bend early prevents damage to the brush or drive gear.