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Maytronics Authorized Dolphin DealerGenuine Maytronics parts with the fit confirmed for your model. Free US shipping on everything we stock.

Genuine Maytronics part · Brushes & Climbing Rings

Front Active Brush, Blue (1 Pack, S)

Part number 99831221-R1 · UPC 810071221804 · 1 year part warranty

A genuine Maytronics blue front brush for Dolphin S200, Dolphin S300, and Dolphin S400.

$7.99 MSRP

Out of stock

Out of Stock

About this part

What it does and when to replace it.

This genuine Maytronics blue front brush helps loosen dirt from pool surfaces as your Dolphin robot cleans.

Maytronics' spec sheet confirms compatibility with Dolphin S200, Dolphin S300, and Dolphin S400. Part 99831221-R1 comes in a one-brush pack and replaces the front brush. Poolbots does not currently stock this part. For help identifying it, contact Poolbots' pool experts by live chat or phone.

Pool expert tips
  • Match part number 99831221-R1 and your exact robot model before choosing a replacement.
  • For help with fit or installation, contact Poolbots' pool experts by live chat or phone.

Compatibility

Fits these Dolphin robots.

Confirmed by Maytronics' compatibility checker and each robot's own spare-parts list.

Also listed by Maytronics for: Dolphin S200, Dolphin S300, Dolphin S400.

Do it yourself

How to replace it at home.

  1. Switch off and unplug the power supply.

  2. Remove the robot from the pool and place it on a stable surface.

  3. Follow your robot's brush replacement instructions to remove the old front brush.

  4. Install the replacement brush in the same position, following those instructions.

  5. Check that the brush is securely fitted before returning the robot to the pool.

Step-by-step answers for this kind of part

How do I replace the climbing rings on my Dolphin brushes?Video20 min
Nautilus CC Plus with Climbing Rings

These steps apply to all Dolphin models equipped with climbing rings.

  1. Step 1: Soak the existing climbing rings Soak the rings in the pool, or leave them in water for 10 minutes. Make sure they are completely soaked before continuing.

  2. Step 2: Turn the robot over Take the robot out of the pool and place it upside down.

  3. Step 3: Check that the power is unplugged Confirm that the power supply is disconnected from the outlet before working on the brushes.

  4. Step 4: Release the brush With a flathead screwdriver, release both sides of the brush from their sockets.

  5. Step 5: Take out the brush Remove the released brush from the robot.

  6. Step 6: Remove the old rings Take the existing climbing rings off the brush.

  7. Step 7: Fit the replacement rings Let the new climbing rings soak in water until they are flexible. Work them onto the brush.

  8. Step 8: Reinstall the brush With the new rings in position, slide the brush into its sockets. Press it into place.

Brush removal and installation videos

These videos show how to remove and reinstall the brushes. Use them as a reference for steps 2-5 and 8.

M Line (DX3/Sigma/Nautilus CC Plus/Nautilus CC Supreme/M400)

How-to video

M600 (Active 60, Explorer E70)

How-to video

For help finding replacement climbing rings, contact Poolbots' pool experts by live chat or phone.

Open this answer on its own page →

How do I replace the brushes on my Dolphin robot?Video30 min

Disconnect the power supply from the electrical outlet before starting. Find the front, middle, or rear brush section below, then follow the video and instructions for your model.

For help choosing a replacement brush, contact Poolbots' pool experts by live chat or phone.

Front brush

S50 (E10, E20/E25, Active 10, Cayman, Escape, Encore)

How-to video

Replacement front brush: 9995544-ASSY.

  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Take the tracks off the robot.
  4. Use a flathead screwdriver to remove the wheel disk.
  5. Turn the wheel until you can see the drive gear's retaining screw through it.
  6. Loosen and remove the screw, then take out the white drive gear.
  7. Ease the old brush out gently.
  8. Slide the replacement brush into position. Put the drive gear back and secure it with its screw.
  9. Put the wheel cover and tracks back on.
  10. Turn the brush by hand to check that it moves smoothly.

S100 (Advantage, Proteus DX3, Saturn, Echo, Nautilus CC, Active 15, Cayman, Escape, Explorer E20)

How-to video
  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Take the tracks off the robot.
  4. Use a flathead screwdriver to remove the wheel disk.
  5. Turn the wheel until you can see the drive gear's retaining screw through it.
  6. Loosen and remove the screw, then take out the white drive gear.
  7. Ease the old brush out gently.
  8. Slide the replacement brush into position. Put the drive gear back and secure it with its screw.
  9. Put the wheel cover and tracks back on.
  10. Turn the brush by hand to check that it moves smoothly.

S200 (E30, Advantage Ultra, Active 20, Quantum, T35, Triton PS)

How-to video
  1. Disconnect the power supply from the electrical outlet.
  2. Take the tracks off the robot.
  3. Use a Phillips screwdriver to remove the four screws securing the brush.
  4. Lift out the old brush.
  5. Fit the replacement brush and secure it with the four screws.
  6. Turn the brush by hand to check for smooth movement.

S300 & S400

S300 (E35/E35i, Proteus DX5i, Active 30, T35/T45, Premium 40, Explorer E30, E40i, Active 30i, T55i)

S400 (E50i, Active 50, Explorer E50)

How-to video
  1. Disconnect the power supply from the electrical outlet.
  2. Take the tracks off the robot.
  3. Use a Phillips screwdriver to remove the four screws securing the brush.
  4. Lift out the old brush.
  5. Fit the replacement brush and secure it with the four screws.
  6. Turn the brush by hand to check for smooth movement.

M400/M500 (Sigma, Oasis, Nautilus CC Supreme, Aquarius XL, C4)

How-to video
  1. Gently push the brush out with a flathead screwdriver until it releases.
  2. Position the replacement brush where the old one sat.
  3. Press the brush inward until it is seated.
  4. Turn the wheels to check that the brush moves properly.

M250 (Nautilus CC Plus, Dx3, Zenit 20)

How-to video

Follow the video for the front-brush replacement procedure.

Premier

How-to video

Follow the video for the front-brush replacement procedure.

Middle brush

M400/M500

How-to video
  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Remove the four screws securing the brush, one at each corner.
  4. Lift the brush out of the robot.
  5. Fit the replacement brush in the same position as the old one.
  6. Reinstall all four screws and tighten them.

Sigma

How-to video

Replacement middle brush: 9995541-R1.

This middle-brush procedure applies to Sigma produced in 2026 or later.

  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Remove the four screws securing the brush, one at each corner.
  4. Lift the brush out of the robot.
  5. Fit the replacement brush in the same position as the old one.
  6. Reinstall all four screws and tighten them.

Rear brush

S200 (E30, Advantage Ultra, Active 20, Quantum, T35, Triton PS)

How-to video

Replacement rear brush: 99955380-ASSY.

  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Take the tracks off the robot.
  4. Carefully free the brush from the notches on both sides, then remove it.
  5. Fit the replacement brush where the old one sat.
  6. Put the tracks back on both sides.
  7. Turn the brush by hand to check for smooth movement.

S300 & S400

S300 (E35/E35i, Proteus DX5i, Active 30, T35/T45, Premium 40, Explorer E30, E40i, Active 30i, T55i)

S400 (E50i, Active 50, Explorer E50)

How-to video

Replacement rear brush: 99955380-ASSY.

  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Take the tracks off the robot.
  4. Carefully free the brush from the notches on both sides, then remove it.
  5. Fit the replacement brush where the old one sat.
  6. Put the tracks back on both sides.
  7. Turn the brush by hand to check for smooth movement.

M400/M500 (Sigma, Oasis, Nautilus CC Supreme, Aquarius XL, C4)

How-to video

Replacement brush assembly: 99955340-ASSY.

  1. Gently push the brush out with a flathead screwdriver until it releases.
  2. Position the replacement brush where the old one sat.
  3. Press the brush inward until it is seated.
  4. Turn the wheels to check that the brush moves properly.

M600/M700 (Active 60, E60i, Explorer E70)

How-to video

Replacement rear brush: 99955340-ASSY.

  1. Disconnect the power supply from the electrical outlet.
  2. Turn the robot over so its underside faces up.
  3. Take the tracks off the robot.
  4. Carefully free the brush from the notches on both sides, then remove it.
  5. Fit the replacement brush where the old one sat.
  6. Put the tracks back on both sides.
  7. Turn the brush by hand to check for smooth movement.

M250 (Nautilus CC Plus, Dx3)

How-to video

Follow the video for the rear-brush replacement procedure.

M550

How-to video

Follow the video for the rear-brush replacement procedure.

Open this answer on its own page →

Specifications

Product Info

Active Brush
No

Size & Dimension

Package Dimensions
17.0x2.4x9.9 inch

General Info

Warranty (years)
1
UPC
810071221804

Questions

Front Active Brush, Blue (1 Pack, S), answered.

Which Dolphin robots fit this brush?

Maytronics' spec sheet lists Dolphin S200, Dolphin S300, and Dolphin S400 as compatible with part 99831221-R1.

How many brushes are included?

This pack contains one blue front replacement brush.

What warranty is listed for this part?

The listed part warranty for 99831221-R1 is 1 year.

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