Maytag MDB8959SKZ – Chopper blade jammed Repair Guide

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Model: Maytag MDB8959SKZ
Brand: Maytag
Model Number: MDB8959SKZ

🔍 Problem Description

Remove and clean chopper assembly; check for broken glass/debris

📋 What You’ll Need

  • Chopper assembly
  • Cleaning tools

    • 🔧 Step-by-Step Repair Instructions

      🔧 Step 1: Remove chopper assembly from dishwasher

      1. Turn off the dishwasher circuit breaker at your electrical panel to cut all power to the unit.
      2. Open the dishwasher door fully until it rests in the horizontal position.
      3. Pull out the lower dishrack completely and set it aside outside the dishwasher.
      4. Locate the circular spray arm at the bottom center of the tub – it’s approximately 8 inches in diameter with multiple spray holes.
      5. Grasp the spray arm with both hands and pull straight upward – it lifts off without any fasteners or clips.
      6. Identify the round filter assembly directly beneath where the spray arm was located in the center of the sump area.
      7. Turn the filter assembly counterclockwise approximately 1/4 turn (90 degrees) until it releases from the locked position.
      8. Lift the entire filter assembly straight up and out – it consists of two connected pieces: an outer cylindrical screen filter and an inner fine mesh filter.
      9. Look down into the circular opening where the filter was seated – you’ll now see the white or gray chopper assembly blade and housing at the bottom of the sump.
      10. Locate the chopper assembly cover, which is a circular plastic component approximately 4 inches in diameter with tabs around its perimeter.
      11. Position your fingers on opposite sides of the chopper cover at the 3 o’clock and 9 o’clock positions.
      12. Turn the chopper cover counterclockwise approximately 1/8 turn until the tabs align with the unlocking notches in the sump housing.
      13. Lift the chopper cover straight up and remove it from the sump opening.
      14. Reach down into the sump and grasp the chopper blade assembly by its hub in the center.
      15. Pull the chopper assembly straight upward – it will lift out freely without any additional fasteners.

      🛠️ Step 2: Inspect for broken glass or debris

      1. Open the dishwasher door fully until it rests in the horizontal position at approximately 90 degrees from the cabinet front.
      2. Remove the bottom dish rack by lifting it straight up and out of the tub, clearing the two front roller assemblies located 3 inches from each front corner.
      3. Unscrew the spray arm center cap by turning it counterclockwise (no tools needed, hand-turn only), then lift the lower spray arm straight up off the central hub.
      4. Position a flashlight at a 45-degree angle pointed toward the sump area (the circular drain opening in the center bottom of the tub, approximately 6 inches in diameter).
      5. Look inside the sump opening for glass shards, food particles, broken dish fragments, toothpicks, or plastic pieces that are visible on the surface.
      6. Put on thick rubber gloves rated for cut resistance.
      7. Use needle-nose pliers (6-inch length minimum) to remove any large debris pieces visible in the sump opening, placing them in a small container beside you.
      8. Unscrew the cylindrical filter assembly by turning it counterclockwise one-quarter turn, then lift it straight up (this is the mesh screen covering the drain, approximately 4 inches tall).
      9. Hold the filter under running water and visually inspect all mesh surfaces for embedded glass or debris, rotating it 360 degrees while examining.
      10. Run your gloved finger along the inside and outside surfaces of the filter mesh to locate any glass shards that may be lodged in the holes.
      11. Inspect the now-exposed sump cavity below where the filter sat, shining the flashlight directly down into the 3-inch deep chamber.
      12. Use needle-nose pliers to extract any remaining debris from the sump cavity, reaching down to the chopper blade assembly (the circular metal disc at the bottom).
      13. Wipe the inside of the sump cavity with a damp microfiber cloth to collect any fine glass particles or debris that pliers cannot grasp.

      ⚙️ Step 3: Clean chopper blade and housing

      1. Locate the chopper blade assembly at the bottom center of the dishwasher tub, directly beneath where the lower spray arm was mounted.
      2. Grasp the circular chopper cover (approximately 4 inches in diameter, white or gray plastic) and rotate it counterclockwise 1/4 turn until it releases from the locking tabs.
      3. Lift the chopper cover straight up and set it aside on your workspace.
      4. Identify the two-blade chopper assembly inside the housing—it resembles a small propeller with two stainless steel blades extending from a central hub.
      5. Grip the chopper blade firmly at the center hub and pull straight upward with moderate force until it lifts free from the motor shaft (approximately 1-2 inches of vertical movement required).
      6. Inspect both the top and bottom surfaces of each blade for food particles, lime deposits, or grease buildup.
      7. Use a stiff nylon brush under running water to scrub both sides of each blade, working from the center hub outward to the blade tips.
      8. Clean the blade edges with a toothpick or wooden skewer to remove any compacted debris lodged in crevices.
      9. Look into the now-exposed chopper housing cavity and remove any visible food particles, bone fragments, or debris using your fingers or needle-nose pliers.
      10. Wipe the interior walls of the housing with a damp cloth wrapped around your index finger, reaching approximately 2 inches deep into the cylindrical chamber.
      11. Flush the housing by pouring 1 cup of clean water directly into the cavity while wiping with the cloth to dislodge remaining particles.
      12. Use a flashlight to verify the housing interior appears clean with no visible debris or buildup remaining.
      13. Dry the chopper blade completely with a lint-free cloth.
      14. Inspect the motor shaft in the housing—it should be a small metal post approximately 0.5 inches tall with a D-shaped or square profile at the center bottom of the cavity.

      🔩 Step 4: Check chopper mechanism for damage

      1. Locate the chopper assembly directly beneath where the spray arm tower was mounted, centered in the sump area at the dishwasher’s base.
      2. Grasp the circular chopper cover (approximately 4 inches in diameter, gray plastic) and rotate it counterclockwise 1/4 turn until the locking tabs release.
      3. Lift the chopper cover straight up and set it aside, exposing the stainless steel chopper blade assembly below.
      4. Remove the chopper blade by lifting it straight up off the center post—it sits loose and requires no tools to remove.
      5. Hold the blade under bright light and examine both the top and bottom cutting edges for chips, cracks, or rounded edges where the blade should be sharp.
      6. Run your finger along the outer rim of the blade checking for missing sections or bent areas—the blade should be perfectly circular with no deformations.
      7. Inspect the black rubber seal on the underside of the chopper cover for tears, missing sections, or hardening—pinch it between your fingers to verify it remains flexible.
      8. Look into the chopper housing cavity and examine the center drive post for cracks or missing splines—you should see 6 raised rectangular teeth evenly spaced around the post.
      9. Rotate the center post by hand clockwise and counterclockwise—it should turn smoothly without grinding sounds or resistance.
      10. Check inside the housing for food debris buildup or hard objects lodged in the chamber—remove any debris with your fingers or needle-nose pliers.
      11. Examine the inside walls of the housing for cracks radiating from the center or chunks of missing plastic.
      12. Verify the blade spins freely when placed back on the center post—wobbling up to 1/8 inch is normal, but more indicates a worn post requiring housing replacement (part number W10830626).

      đź“‹ Step 5: Replace chopper assembly if blade is damaged or mechanism is broken

      1. Grasp the cylindrical chopper cover (3 inches diameter, gray plastic) located at the center bottom of the dishwasher tub and rotate counterclockwise 1/4 turn until the locking tabs align with the slots.
      2. Lift the cover straight up and set aside—you’ll see the stainless steel chopper blade assembly beneath.
      3. Locate the center mounting nut (8mm hex nut) securing the chopper blade to the motor shaft.
      4. Hold the chopper blade stationary with one hand while using an 8mm socket wrench to turn the mounting nut counterclockwise 3-4 full rotations until completely free.
      5. Remove the nut and any washers present (typically one flat washer and one lock washer) and place them in a container.
      6. Lift the damaged chopper blade assembly straight up off the motor shaft—it should slide off with minimal resistance.
      7. Wipe the exposed motor shaft clean using a dry cloth to remove any food debris or mineral deposits.
      8. Position the new chopper assembly (part number W10083957V or W11374446) over the motor shaft, aligning the blade’s center hole with the shaft’s flat side to the flat section inside the blade hub.
      9. Slide the new assembly down until it sits flush against the pump housing base.
      10. Place the lock washer onto the shaft first (ridged side facing up), followed by the flat washer.
      11. Thread the 8mm hex nut onto the shaft by hand, turning clockwise until finger-tight.
      12. Hold the blade stationary and tighten the nut with the 8mm socket wrench to 10-12 ft-lbs using a torque wrench—approximately 1/4 turn past finger-tight resistance.
      13. Spin the blade manually in both directions—it should rotate freely without wobbling or catching.
      14. Align the chopper cover tabs with the housing slots, press down firmly, and rotate clockwise 1/4 turn until it locks into position with an audible click.

      đź›’ Recommended Products

      Here are the recommended products for this repair: