Short answer: For 320-class and 330/336-class machines the fast movers fall into five groups: filters (fuel/oil/hydraulic/air), undercarriage, cylinder seal kits, pins & bushings, swing & travel parts. Stock by these five groups and you get minimum capital tied up with maximum uptime.
Five groups with example numbers
| Group | Typical items | Example part numbers |
|---|
| Filters | Fuel, oil, hydraulic return, air | 1R-0736 / 1R-0749 (fuel) |
| Undercarriage | Rollers, sprockets, bushings | 357-5717 bushing group and family |
| Cylinder service | Boom/arm/bucket seal kits | Match by cylinder stamp |
| Ground tools | Pins, bushings, links | Match by bore size |
| Swing / travel | Swing bearing, travel seals | Match by motor serial |
Numbers above are format/family examples — always confirm against your machine's serial range. We cross-reference the full CAT line;
All Parts search.
Stocking rules of thumb
- Consumables (filters, seals): per 500-hour service interval × fleet size.
- Undercarriage: per measured wear trend, replaced in matched sets.
- Everything else: order per event — shipping is fast enough that shelf stock is unnecessary.
Frequently asked questions
Do 320 and 320 GC share parts?
Consumables mostly yes; hydraulics and structure differ — confirm per item with the serial number.
Can you assemble a full 500-hour service kit?
Yes — send machine model and hours, we quote the complete kit in one order.
Stocking for a CAT fleet?
Send your model list — we build the fast-mover list with prices.