Why Does the Accumulator Diaphragm Burst? Signs of Failure
26 November 2025
Inside the accumulator located on top or on the side of hydraulic breakers, there is a rubber part called the Diaphragm. This part separates the nitrogen gas from the hydraulic oil and absorbs instantaneous pressure spikes.
The source of the problem operators describe as "hoses whipping" is usually a burst diaphragm.
1. What Happens If the Diaphragm Bursts?
When the diaphragm tears, nitrogen gas mixes into the hydraulic system. Signs include:
- Excessive Vibration: The breaker's hydraulic hoses shake violently (Whipping).
- Power Loss: The breaker cannot strike as fast or powerfully as before.
- Pump Damage: If left unrepaired, pressure spikes can damage the excavator's main pump.
2. Why Does the Diaphragm Tear?
Common causes are:
| Cause | Explanation |
| Low Gas Pressure | If gas is low, the diaphragm collapses under oil pressure and rubs against the sides, tearing it. |
| Cold Weather Operation | Rubber hardens in the cold. Operating at full speed without warming up cracks the diaphragm. |
| Poor Quality Material | Aftermarket diaphragms lose elasticity quickly. |
3. Compatible Brands
HKM stocks accumulator and diaphragm parts compatible with the following brands:
- Furukawa: F 22, F 35, F 45 and FX series.
- Soosan: SB 81, SB 121, SB 151.
- Atlas Copco: HB 2000, HB 2500, HB 3000.
- Rammer: E 68, G 80, G 100.
- Others: Montabert V series, MSB, Daemo, D&A, Okada, Toku, NPK, MTB.