Side Bolt Loosening and Body Damage Relationship
26 November 2025
Side Bolts secure the breaker power cell to the outer bracket (housing). They are vital, especially in Korean/Japanese designed breakers like Furukawa (FRD), Soosan, and Daemo.
If your side bolts loosen, the breaker starts to "dance" inside the housing. This vibration destroys the front head and hoses.
1. What Happens If Side Bolts Loosen?
You usually cannot see the loosening with the naked eye, but the consequences are severe:
- Body Wear: The breaker eats into the plates inside the bracket, leading to metal-on-metal friction.
- Bolt Shearing: Loose bolts are subjected to shock and snap suddenly.
- Hose Burst: Since the breaker moves inside the bracket, hydraulic hoses stretch and break.
2. Maintenance Tips
To extend the life of side bolts:
| Action | Explanation |
| Torque Check | Check nut torque every 50 hours. |
| Polyurethane Buffers | If the rubber/polyurethane buffers under the side bolts are crushed, replace them immediately. Otherwise, the bolt takes direct impact. |
| Lock Washer | Always install original lock washers or tab washers under the nuts. |
3. Compatible Brands
HKM side bolts and housing bolt sets are manufactured from special high-strength steel for the following brands:
- Furukawa (FRD): F and FX series.
- Soosan & Daemo & DNB: SB and DMB series.
- MSB & D&A: Saga and MS series.
- Okada & Toku: Japanese standard production.
- MTB and all other models.