5-87831597-0 Clutch Master Cylinder Repair Kit 3/4 Inch Bore with 12 Months or

The Clutch Master Cylinder Repair Kit with OEM numbers 5-87831597-0 / 5878315970 is a verified direct-fit replacement for ISUZU NKR, NPR, NHR, and ELF trucks equipped with 4HF1 and 4JB1 diesel engines. This complete seal restoration kit is designed to repair pressure leakage caused by aged or worn seals, restoring proper clutch hydraulic system operation without replacing the entire master cylinder.

The clutch master cylinder is a core component of the hydraulic clutch system, responsible for converting clutch pedal force into hydraulic pressure transmitted to the clutch slave cylinder to disengage the clutch. When internal seals age or wear, it causes a spongy pedal, incomplete clutch disengagement, or inability to shift gears. Timely replacement of the repair kit restores proper clutch system operation.

• Real Specification Data: Bore diameter 3/4 inch (19.05 mm). Brand Nakamoto / NAP / SEIKEN. Origin Taiwan / China. Packaging Neutral Packaging. Condition New. Size and weight Standard.
• Proven Durability: Supplier offers 12-month or 20,000 km warranty (whichever occurs first). Payment terms L/C, T/T, Western Union. Supply ability 100,000,000/month (per supplier data).
• Fitment Confirmed: Standard mounting dimensions, direct replacement design, manufactured to OEM specifications — verified against OEM standard dimensions. Fits NKR-55/58/66, NKR-71, NPR66, NPR94 models.
• OEM Cross-Reference Verified: Replaces ISUZU OEM numbers 5878311970, 5878309420, 8941580510, 8-94158-051-0, 5878314031, 5878322260. International brand alternatives include SEIKEN 210-83071 / SK83071, FRENKIT 419035, AUTOFREN SEINSA D1472, NAP 5878315970.

When the clutch master cylinder exhibits the following conditions, timely inspection and repair kit replacement are required:

1. Spongy clutch pedal or increased travel: Aged internal seals causing hydraulic pressure leakage, pedal feels weak or returns slowly.
2. Incomplete clutch disengagement or inability to shift: Insufficient hydraulic pressure, clutch cannot fully disengage, causing difficult shifting or gear grinding.
3. External oil leakage from clutch master cylinder: Brake fluid seepage at push rod oil seal or dust boot, visible oil stains on cylinder exterior.
4. Pedal does not return or returns slowly: Internal piston sticking or spring failure, pedal fails to return properly.
5. Continuous brake fluid level drop: Internal seal failure causing brake fluid leakage into dust boot or exterior, abnormal fluid level drop.

Certification: Supplier declares testing on every unit. Brand manufacturer holds ISO/TS16949 and related quality management system certifications.

1. Preparation: Disconnect negative battery terminal, extract brake fluid from reservoir using a syringe or suction tool to prevent fluid overflow and paint damage.
2. Remove master cylinder: Remove clevis pin connecting master cylinder to pedal push rod, disconnect hydraulic line fitting (use flare nut wrench to prevent fitting damage), remove master cylinder mounting bolts.
3. Disassemble master cylinder: Remove circlip, sequentially extract push rod, piston, spring, and old seals. Thoroughly clean master cylinder bore.
4. Install new seals: Apply appropriate brake fluid to seals for lubrication, install new seals, piston, and spring in correct orientation.
5. Assemble master cylinder: Install circlip to secure, confirm piston moves smoothly without binding.
6. Install master cylinder: Reinstall master cylinder in original position, tighten mounting bolts and hydraulic line fittings to specified torque.
7. Bleeding procedure: Fill with new brake fluid, bleed air from hydraulic system per workshop manual method until pedal feels firm.
8. Function test: Start engine, test clutch disengagement and engagement, check all fittings for leakage.

• Every 20,000 km or 12 months: Check clutch pedal free play and operating feel, inspect master cylinder for leakage.
• Every 50,000 km: Check brake fluid level and quality, replace brake fluid if necessary.
• When spongy pedal or abnormal clutch disengagement is detected: Inspect master cylinder seal condition promptly and replace repair kit if necessary.