Hayward Robotic Cleaner Brush and Track Problems: Diagnosis and Repair
Quick Summary
- Brush and track problems fall into two categories: drive system problems (drive belt, pulleys, and bearings) that prevent the tracks from moving, and brush problems (worn brush bristles or a detached brush) that allow movement without scrubbing.
- Accessing the drive system requires removing the side cover — 7 Torx screws on TigerShark (drive-side cover only), 4 T20 screws per side cover on SharkVac/AquaVac/E-Vac.
- Drive belt cogs wear from the inside of the belt loop. Inspect the inner surface, not just the outer face, for missing or broken cogs and cracks.
- Idler pulley bearings should spin freely and silently by hand. A pulley that grinds, sticks, or makes noise has failed and must be replaced.
Understanding the Drive System
Hayward robotic cleaners use a belt-and-pulley drive system to convert motor rotation into track movement. The drive motor's output shaft turns a main drive pulley via a keyed connection — a drive pin on the motor output shaft mates with a corresponding key slot in the main drive pulley. The main drive pulley drives the drive belt, which wraps around two or three idler pulleys and ultimately turns the wheel tube assemblies that drive the tracks.
The brush assembly is a separate component from the drive system. The brushes are mounted on the exterior of the cleaner body and rotate as the tracks move across the pool surface, agitating debris into the suction stream. Brush problems (worn bristles, detached segments) and drive system problems (belt, pulleys, bearings) can look similar from the outside but require completely different repairs.
Accessing the Drive System
TigerShark Side Cover Removal
The TigerShark has a drive-side cover on the side opposite the power cord entry point. This is the side with the drive belt and pulleys. The other side (motor side) does not typically require removal for drive system inspection.
- Remove the cleaner from the pool, power off, and place it on a clean flat surface with the drive-side cover facing up.
- Locate the 7 Torx screws around the perimeter of the drive-side cover. Use the appropriate Torx bit — do not substitute a flat screwdriver, as this will strip the screw heads.
- Remove all 7 screws and set them aside. The cover will lift off to expose the drive belt, idler pulleys, main drive pulley, and wheel tube assemblies.
SharkVac, AquaVac, and E-Vac Side Cover Removal
SharkVac-family cleaners have removable covers on both sides of the body. The drive system is accessible from either side.
- Remove the cleaner from the pool, power off, and place it on a flat surface.
- Locate the 4 T20 Torx screws on the side cover. Remove all 4 screws.
- Lift the cover off. Repeat on the opposite side if inspection of both sides is needed.
Drive Belt Inspection
The drive belt is a toothed (cogged) belt that transmits rotation from the main drive pulley to the idler pulleys and ultimately the wheel tubes. Belt wear is on the inner surface — the side with the cogs that mesh with the pulley teeth. The outer surface often looks normal even when the inner surface has significant damage.
What to Look For
- Missing cogs — Individual cog segments can tear away from the inner belt surface. A missing cog allows the belt to skip on the pulley, causing the tracks to slip or stop intermittently. Even one missing cog can cause significant performance loss.
- Broken cogs — A cog that is cracked but still attached will eventually tear away under load. Inspect carefully by flexing the belt section by section.
- Cracks in the belt body — Transverse cracks across the belt (perpendicular to the belt length) indicate the belt is aging and about to fail. Replace immediately if cracks are present.
- Belt seated off a pulley — The belt can jump off a pulley after a drive motor overcurrent event or an obstruction. Reseat the belt on all pulleys if it is not properly engaged.
Inspect the Inner Loop, Not Just the Outside
New technicians often inspect only the outer face of the drive belt and conclude it is in good condition. Always rotate the belt by hand to expose and inspect the full inner loop. Missing or broken cogs on the inner surface are the most common cause of belt-related drive problems and are invisible from the outside.
Idler Pulley Inspection
Idler pulleys are the intermediate pulleys that route and tension the drive belt. TigerShark models have 2–3 idler pulleys per drive side. Each idler pulley has an internal bearing that allows it to rotate on a fixed shaft. When the bearing fails, the pulley resists rotation — adding drag to the drive belt and increasing the load on the drive motor, which shows up as Drive Overcurrent events on the Hayward Scanner.
Bearing Test Procedure
- With the side cover removed, spin each idler pulley by hand. The pulley should rotate freely and silently.
- A pulley that is stiff, grinds, clicks, or wobbles has a failed bearing and must be replaced. Individual idler pulleys are available as replacement parts — the entire drive system does not need to be replaced for a single failed pulley.
- Note the pulley flange orientation when removing. The flange on idler pulleys faces inward (toward the center of the cleaner) when installed. Installing a pulley with the flange facing outward will prevent the drive belt from tracking correctly.
Main Drive Pulley and Motor Key Inspection
The main drive pulley connects directly to the motor output shaft via a keyed connection. A drive pin on the motor shaft mates with a corresponding slot (key) in the hub of the main drive pulley. If this pin shears or the key is damaged, the motor shaft rotates without turning the pulley — and the entire drive system stops while the motor runs freely.
To check the key connection: with the belt in place and the motor running (briefly, on the bench, out of the pool), observe whether the main drive pulley rotates when the motor runs. If the motor runs but the pulley does not rotate, the key connection has failed. The complete motor assembly must be replaced — the output shaft drive pin is not a separately serviceable part.
Wheel Tube Bearing Screws
The wheel tube assemblies are the large cylindrical rollers that contact the pool surface and drive the tracks. Each wheel tube has a bearing assembly at each end, secured by a bearing screw. There are 2 bearing screws per side (4 total across the cleaner). If a bearing screw is missing or loose, the bearing assembly can slip, causing the wheel tube to rotate without driving the track effectively.
Inspect all bearing screws with the side cover removed. Each screw should be present and tightened firmly. Replace any missing screws with the correct fastener for the model — using a screw that is too short or too long can damage the bearing assembly.
Brush Assembly Inspection and Replacement
The brush assemblies on Hayward robotic cleaners consist of multiple brush segments that clip onto a brush carrier bar running along the side of the cleaner body. Each segment has a row of bristles and is secured by snap tabs that lock into corresponding slots in the carrier bar.
Identifying Brush Wear
- Worn bristle height — New brushes have bristles of a uniform height. As bristles wear, they shorten. Brushes that have worn down to the base of the bristle rows can no longer agitate debris effectively. Compare bristle height to a new brush segment if available.
- Detached brush segments — A segment that has unclipped from the carrier bar will drag behind the cleaner or foul the tracks. Check that all segments are fully snapped into position.
- Missing segments — Segments left in the pool after detachment. Count the segments and compare to the model's specified count.
Brush Segment Replacement Procedure
- To remove a brush segment, use needle-nose pliers to unsnap each tab lengthwise along the segment. Work from one end to the other — do not try to pull the segment away from the bar without releasing each tab, as this can break the tabs.
- Position the new segment over the carrier bar with the bristles facing outward and downward.
- Starting at the center of the segment, press each mounting post through its corresponding tab hole in the carrier bar.
- Push each post down and inward until the tab locks with an audible click. Work outward from center to the ends of the segment.
- Confirm each tab is fully locked by attempting to pull the segment away from the carrier bar — it should not release without the pliers.
Frequently Asked Questions
One track moves but the other is stopped. What causes one-sided drive failure?
One-sided drive failure is almost always a problem with the belt, pulleys, or bearings on that specific side — not the drive motor itself. The drive motor drives both sides through the same output shaft. If one side is stopped while the other moves, remove the side cover on the stopped side and inspect the belt for missing cogs and the idler pulleys for seized bearings. In some cases the drive belt has jumped off a pulley on one side after an obstruction, leaving the other side functional.
How often should drive belts be replaced as preventive maintenance?
Hayward does not publish a fixed belt replacement interval — replacement is condition-based. Inspect the inner loop of each drive belt at the start of every pool season. Replace immediately if any cogs are missing or cracked. A belt with no missing cogs but with surface cracking in the body should be replaced as a precaution before it fails mid-season. Belts on cleaners that run frequently (3+ times per week) typically last 2–3 seasons before showing wear. Cleaners with occasional obstruction events (Drive Overcurrent on the Scanner) may show accelerated belt wear.
After replacing the drive belt, the cleaner moves but makes a slapping or ticking sound. What is wrong?
A slapping or rhythmic ticking sound after belt replacement usually means the belt is not fully seated on all pulleys. One pulley tooth is catching or skipping on the belt. Remove the side cover and verify the belt is properly engaged on all pulleys — the belt teeth should mesh with every pulley tooth with no gaps. Also check that no debris is caught between the belt and a pulley. If the belt is correctly seated and the sound persists, the belt may be the wrong part number and is slightly mismatched to the pulley pitch.
The brush bristles are still in good shape but the cleaner leaves visible marks on the pool surface. What should I check?
Visible marks or scratches on the pool surface from a robotic cleaner are usually caused by a worn or deformed brush segment frame (not the bristles themselves) contacting the surface, or by debris lodged between the brush and the pool surface. Inspect each brush segment for deformation, cracks in the plastic carrier frame, or any foreign material (stones, shell fragments) trapped in the brush assembly. Also confirm the brush segments are all correctly locked — a partially detached segment can contact the pool surface at an angle.
Is it possible to replace just one idler pulley, or does the entire set need to be replaced together?
Individual idler pulleys are available as replacement parts and can be replaced one at a time. There is no requirement to replace all idler pulleys simultaneously. However, if one pulley bearing has failed on a cleaner with significant hours, the remaining pulleys are likely close to the same wear point. Replacing all idler pulleys as a set during a repair visit avoids a callback for another failed pulley later in the same season. At minimum, spin each remaining pulley by hand after replacing the failed one to assess their condition.