What Happens If the Retaining Pin Wears Out?
26 November 2025
The part that secures the tool (chisel) to the breaker body is the Retaining Pin (Kama). Although it seems like a small part, it is the only safety lock holding the tool.
Whether you use a breaker with smart systems like Indeco, or Japanese/Korean models like Okada or D&A; if the pin wears out, your tool will fall out or get jammed.
1. Why Does the Pin Break or Wear?
The pin absorbs the recoil force of the tool with every strike. If left ungreased or if the tolerance increases, the following problems occur:
- Ovalization: The pin slot or the pin itself becomes egg-shaped. This causes the tool to wobble and break the piston.
- Breakage: Low-quality aftermarket pins cannot withstand metal fatigue in high-impact breakers like Krupp or Rammer and snap in half.
2. When to Replace the Pin?
The pin must be replaced when surface wear exceeds a certain level. Otherwise, it damages the Front Head housing.
| Part | Check | Risk |
| Main Retainer Pin | Notches or dents on surface | Tool jamming, housing cracks. |
| Lock Pin (Susta) | Rubber and spring elasticity | Pin falling out of place. |
3. Compatible Brands
HKM retaining pins are tested in the toughest site conditions. We manufacture fully compatible aftermarket parts for the following brands:
- Atlas Copco (Epiroc): SB 81, SB 102, HB 2000, HB 3000.
- Rammer: S 23, S 25, E 68, G 80.
- Furukawa (FRD): F 5, F 9, F 22, F 35.
- Montabert: SC 36, V 1200, V 32.
- Others: Soosan SB 81, MSB, Daemo, Okada, MTB.