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Rear Brake Wheel Cylinder with High-Strength Cast Iron 1-3/16" Bore and 16-Tooth Adjustment Gear for ISUZU NKR NPR

Basic Properties
Place of Origin: CHINA
Brand Name: YIMI
Certification: ISO/TS16949
Model Number: NKR NPR 4BD1 4HF1
Trading Properties
Minimum Order Quantity: 20 PCS
Price: Negotiable
Payment Terms: T/T
Supply Ability: 10000 pcs/month
Specifications
Bore Diameter: 1-3/16" (30.16mm) Adjustment Gear: 16 Teeth
Net Weight: 1.23kg Material: High-strength Cast Iron
Bore Precision: 30.16±0.013mm Surface Finish: Ra≤0.4μm
Pressure Seal: 15MPa Static Pressure Held For 30 Seconds Durability Test: 500,000 Full-stroke Pressure Cycles
High Light:

High-strength cast iron Rear Brake Wheel Cylinder

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1-3/16" bore diameter Brake Wheel Cylinder

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16-tooth adjustment gear Wheel Cylinder

Product Description
Rear Brake Wheel Cylinder 8971398220 8-97139822-0 for ISUZU NKR NPR 4BD1 4HF1
Rear Brake Wheel Cylinder (R) 8971398220 8-97139822-0 for ISUZU NKR NPR 4BD1 4HF1 — Verified OEM Fit
The Rear Brake Wheel Cylinder with OEM numbers 8971398220 / 8-97139822-0 is a verified direct-fit replacement for ISUZU NKR / NPR series light trucks equipped with 4BD1 or 4HF1 engines. This wheel cylinder is a critical component of the rear drum brake system (right-hand / rear right position), responsible for converting hydraulic pressure from the brake master cylinder into mechanical force that pushes the brake shoes against the brake drum, slowing or stopping the vehicle.
How It Works
When the driver presses the brake pedal, brake fluid flows from the master cylinder through the brake lines into the rear wheel cylinder. The hydraulic pressure forces the pistons inside the cylinder outward, pushing the brake shoes against the inner surface of the brake drum. Friction converts the vehicle's kinetic energy into heat, achieving braking. When the pedal is released, return springs retract the pistons, releasing the brakes.
Failure Symptoms (Replace immediately if any occur)
  • Brake Fluid Leakage — Visible oil stains around the wheel cylinder; brake fluid level drops consistently
  • Vehicle Pulls to One Side — Vehicle veers to one side during braking; single-side cylinder sticking
  • Low/Spongy Brake Pedal — Increased pedal travel; reduced braking force
  • Brake Noise — Metallic grinding or squealing during braking
  • Brake Drag — Vehicle feels like brakes are still applied after releasing pedal; pistons fail to retract
  • Reduced Parking Brake Performance — Vehicle still moves when parking brake is applied
Verified Data (2025 Algorithm Signals)
  • Installation Success Rate : 97.8% direct bolt-on fitment — confirmed across 89 repair orders (Jan 2024 – Jun 2025)
  • Bench Durability Test : 500,000 full-stroke pressure cycles (0–10MPa) — zero leakage, piston stroke degradation <3% (Test Report #BWC-8971398220-2024)
  • Pressure Seal Integrity : 15MPa static pressure held for 30 seconds — zero pressure drop; 100% factory tested (ISO 6117)
  • Bore Precision : 1-3/16" (30.16mm) precision-honed cylinder bore, surface roughness Ra≤0.4μm — CMM verified
  • Material Verification : High-strength cast iron body, hardness HB190–230 — material spectrographic analysis report included
  • Adjustment Gear : 16-tooth adjustment gear for precise brake shoe clearance adjustment
ISUZU Rear Brake Wheel Cylinder 8971398220
Part Number: 8971398220 8-97139822-0 Product Name: Rear Brake Wheel Cylinder
Car Model: NKR NPR Engine Model: 4BD1 4HF1
Condition: 100% Brand New Size: Standard
Weight: Standard Origin: China Mainland
Main Market: Middle East, Asia, Africa, South America, North America & Europe
Package: Neutral Packing Or Make It As Requested
Material: High-strength aluminum alloy & precision bearings
Cooling Type: Engine coolant circulation
Installation: Direct OEM replacement
Quality Standard: OEM equivalent / ISO quality control
Vehicle & Engine Compatibility
Primary Applications:
Brand Model Chassis Engine Years
ISUZU ELF NKR / NPR / NQR 4BD1 / 4HF1
ISUZU ELF 250 NKR66 4HF1 1994–1998
ISUZU ELF 350 NQR55/58/59/65/66/69/70/71 4HF1 1994–2000
ISUZU NPR NPR55/58/66/69/70/71 4HF1 1994–2000
ISUZU NPR NPR59 4BD1/T 3.9L 1984–1994
ISUZU NPR NPR250 4HF1 4.3L 1993–2006
ISUZU NPR / NKR / NQR 4BE1 / 4HG1 / 4HK1 / 4JJ1
ISUZU NLR / NMR / NPS 4BD1 / 4HF1
⚠️ Important:
  • This is a REAR RIGHT (R.H.) brake wheel cylinder
  • Confirm your vehicle has drum brake system before purchase
  • Recommended to replace both left and right wheel cylinders simultaneously for balanced braking
  • For 100% accurate fitment, please provide VIN (Chassis Number)
Features & Benefits
High-Strength Cast Iron Body
Withstands high pressure and thermal cycling — verified by 500-hour thermal cycle test (-30°C to +150°C); no cracks, no deformation
Precision-Honed 1-3/16" Bore
Ensures smooth, consistent hydraulic pressure transfer for responsive, reliable braking — bore roundness ≤0.005mm, Ra≤0.4μm; CMM verified
100% Pressure Leak Tested
Every cylinder undergoes 15MPa air/hydraulic dual leak test — 30-second hold with zero pressure drop; 100% pass rate (ISO 6117)
Direct OE Fit Replacement
No modification needed for quick, hassle-free installation — 97.8% bolt-on fitment rate confirmed across 89 repair orders
16-Tooth Adjustment Gear
Easy brake system bleeding and precise shoe gap adjustment — convenient maintenance, no special tools required
Copper Bleeder Screw
Corrosion-resistant with excellent sealing — 100% copper material, 72-hour salt spray test with no rust
12-Month Warranty
Peace of mind on manufacturing defects — free replacement within warranty period
Quality Control & Verification
QC Item Verification Method Standard
Material Composition Spectrographic analysis Meets HT250 cast iron standard
Body Hardness Brinell hardness tester HB190–230
Bore Dimensional Accuracy CMM coordinate measuring machine 30.16±0.013mm
Bore Surface Finish Roughness tester Ra≤0.4μm
Pressure Leak Test Air + hydraulic dual test 15MPa hold 30s zero leak (ISO 6117)
Piston Sliding Resistance Universal testing machine ≤3.5N (dry condition)
Durability Test Bench cycle test 500,000 full-stroke pressure cycles no failure
Visual & Dimensional Inspection 100% visual + gauge inspection No porosity, blowholes, or burrs
Thread Inspection Thread go/no-go gauge M10*1 thread certified
Installation & Maintenance Recommendations
⚠️ IMPORTANT:
The brake system is critical to vehicle safety. Installation should be performed by qualified professionals. Always bleed the brake system and perform a road test after installation.
Installation Guidelines (Refer to workshop manual):
  1. Safety Prep : Park on level ground, chock wheels, lift and support vehicle
  2. Remove Old Cylinder : Disconnect brake line (catch draining fluid), remove mounting bolts (2*M10 bolts, torque 15–18N·m)
  3. Clean Mounting Surface : Thoroughly remove rust and debris from mounting face
  4. Install New Cylinder : Mount new cylinder, torque bolts to 15–18N·m
  5. Connect Brake Line : Attach brake hard line, torque to 14–16N·m
  6. Bleed Brake System : Bleed in sequence (RR → LR → RF → LF) until no air bubbles appear (use the copper bleeder screw)
  7. Adjust Clearance : Use the 16-tooth adjustment gear on the cylinder to set proper brake shoe clearance
  8. Road Test : Perform brake test at 30km/h — confirm smooth braking, no pulling, no noise
Maintenance Schedule:
Item Interval
Brake Fluid Replacement Every 2 years or 40,000 km
Wheel Cylinder Inspection Every 10,000 km or 6 months
Brake Shoe Inspection Every 10,000 km
Cylinder Replacement When leakage/sticking occurs, or at 80,000–100,000 km
Packaging & Supply
  • Packaging : Neutral carton / Color box / Custom branded packaging
  • Packaging Unit : 1 piece/box
  • Carton Dimensions : 12*10*7cm
  • Net Weight : 1.23kg
  • MOQ : Small orders accepted; volume discounts available
  • Target Customers : Truck parts wholesalers, repair chain stores, fleet purchasers, cross-border e-commerce sellers