Seiko 4402A - Parts List
Seiko 4402A – Technical Guide
General Overview
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Movement Caliber: Seiko 4402A
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Type: Manual-wind mechanical movement
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Manufacturer: Daini Seikosha (Seiko Instruments Inc.)
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Production Period: 1960s
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Series: 44xx series
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Primary Use: Grand Seiko and King Seiko models
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Key Feature: High-grade, hand-wound movement with date complication
Technical Specifications
| Feature | Specification |
|---|---|
| Winding System | Manual only |
| Jewels | 25 |
| Frequency | 18,000 A/h (5 beats per second) |
| Power Reserve | ~45 hours |
| Shock Protection | Diashock |
| Hacking Seconds | No |
| Calendar | Date only, semi-quickset via 21–24h cycling |
| Movement Diameter | ~27.6 mm |
| Movement Height | ~5.3 mm |
| Finishing | Brushed bridges, polished screw heads |
Functional Description
The Seiko 4402A is part of the 44-series family, known for powering both Grand Seiko and King Seiko models. It is a manual-wind movement built to exceptional standards for its time, offering accuracy, durability, and a classic design. Its date mechanism is semi-quickset, requiring repeated hand rotations around midnight.
Crown Operation
| Position | Function |
|---|---|
| 0 | Winding (manual only) |
| 1 | Time setting |
There is no direct quickset feature. The date is changed by advancing the hands past midnight and then reversing past ~9:00 PM, repeating until the desired date is reached.
Calendar System
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Date Display: Numeric (1–31)
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Semi-quickset: Adjusted by cycling hands between ~21:00 and 24:00
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Drive Mechanism: Cam and date jumper with spring loading
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Changeover Time: Gradual start ~23:30, completes near midnight
Watch Applications
The 4402A was used in several high-grade models including:
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King Seiko 4402-8000 / 8001
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King Seiko Chronometer models (marked "Chronometer Officially Certified")
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Some rare Seiko Champion watches in early versions
These watches featured clean dials, solid stainless steel cases, and casebacks with the Seiko lion medallion.
Disassembly and Servicing Notes
| Component | Watchmaker Notes |
|---|---|
| Date Jumper and Spring | Use Rodico to prevent loss when removing the date plate |
| Train Bridge | Supports multiple wheels; confirm pivot alignment carefully |
| Balance Cock | Diashock-protected — inspect cap jewels and lubricate properly |
| Keyless Works | Standard sliding clutch with visible setting lever spring |
| Barrel | Replace mainspring during overhaul for optimal power retention |
Lubrication Guide
| Location | Lubricant Type |
|---|---|
| Train Wheel Pivots | Moebius 9010 |
| Escape Wheel Teeth | Moebius 941 |
| Pallet Stones | Moebius 941 |
| Balance Cap Jewels | Moebius 9010 |
| Mainspring (Arbor & Barrel Wall) | Moebius 8200 |
| Keyless Works | Molykote DX |
Performance Benchmarks
| Metric | Post-Service Target |
|---|---|
| Daily Accuracy | ±10 to ±15 seconds/day (regulated) |
| Amplitude | 250°–280° fully wound (horizontal) |
| Beat Error | ≤ 0.5 ms |
When properly regulated, 4402A movements are capable of chronometer-level performance, as originally intended in many models.
Common Issues and Solutions
| Problem | Likely Cause | Solution |
|---|---|---|
| Date won't advance | Worn or gummed-up date jumper spring | Clean or replace spring and jumper |
| Low amplitude | Old lubrication or worn mainspring | Full cleaning, replace mainspring |
| Hands slipping during set | Worn cannon pinion | Tighten or replace cannon pinion |
| Inconsistent accuracy | Dirty escapement or dry pivots | Clean and re-lubricate entire train |
Collectibility and Value
The 4402A is highly respected among vintage Seiko collectors, especially when housed in King Seiko Chronometer cases. It represents Seiko’s pursuit of high-precision mechanical watchmaking in the pre-Quartz era.
| Condition | Value Range |
|---|---|
| Working, non-serviced | $250–$400 |
| Serviced or near mint | $500–$800+ |
| Rare dials or original boxes | $900–$1200+ |
Conclusion
The Seiko 4402A is a classic, high-quality manual movement known for its precision, durability, and historical importance in the evolution of King Seiko watches. Its robust construction, clean aesthetics, and reliable calendar system make it a standout choice for collectors and a rewarding caliber for restoration.
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