How to Grease a Hydraulic Breaker Correctly
Greasing is the single most important routine maintenance task for a hydraulic breaker. Insufficient or incorrect greasing is the leading cause of premature chisel bushing wear, front head damage, and chisel breakage. This guide covers the correct procedure, frequency, grease specification, and the most common mistakes operators make.
Safety Precautions
- Always lower the breaker to the ground and shut down the excavator before greasing.
- Never grease a hot breaker immediately after operation — allow 5 minutes to cool.
- Do not use standard lithium grease — use only manufacturer-specified chisel paste.
Why Greasing Matters
The chisel (tool) of a hydraulic breaker operates under extreme conditions — repeated high-energy impacts, lateral forces, and abrasive contact with rock and concrete. The only thing protecting the chisel bushing and front head bore from metal-to-metal contact is a thin film of grease.
Without adequate lubrication, the chisel bushing wears rapidly, allowing the chisel to develop lateral play. This lateral movement causes uneven loading on the piston, accelerates wear on the front head bore, and can ultimately lead to chisel breakage or front head cracking.
Proper greasing extends chisel life by 2–3x, protects the front head bushing (a major repair cost), and maintains consistent breaking performance throughout the chisel's service life.
Greasing Frequency
The standard greasing interval for most hydraulic breakers is every 2 hours of operation. However, this should be adjusted based on conditions:
Normal conditions (concrete, soft rock)
Grease every 2 hours of operation. This is the baseline interval for most construction applications.
Abrasive conditions (granite, basalt, abrasive sand)
Grease every 1 hour. Abrasive materials accelerate bushing wear and consume grease faster.
In highly abrasive granite or basalt, some operators grease every 30–45 minutes. Monitor bushing wear closely.
Wet or muddy conditions
Grease every 1–2 hours. Water and mud wash grease out of the bushing area faster than dry conditions.
Cold weather operation
Grease at the start of each shift and every 2 hours thereafter. Cold temperatures increase grease viscosity and reduce its ability to flow into the bushing.
In temperatures below 0°C, use a low-temperature chisel paste grease if available.
Correct Greasing Procedure
Follow these steps every time you grease the breaker:
Lower the breaker and shut down
Lower the breaker to the ground so the chisel is in contact with the work surface. Shut down the excavator completely. This positions the chisel correctly for greasing and ensures safety.
Locate the grease fitting
The grease fitting (Zerk fitting) is located on the front head of the breaker, typically on the side or front face. Some models have two fittings — one on each side. Wipe the fitting clean with a rag before attaching the grease gun.
Apply the correct amount of grease
Apply 3–5 pumps of grease from a standard grease gun. The goal is to coat the chisel bushing — not to pack the front head with grease.
Over-greasing is a common mistake. Excessive grease can enter the hydraulic circuit through the back cap, contaminating the hydraulic oil. Apply only the recommended amount.
You should see a small amount of fresh grease appear at the bottom of the front head (around the chisel) after greasing. This confirms the grease has reached the bushing.
Rotate the chisel
After greasing, rotate the chisel 90° by hand (or with a strap wrench if tight). This distributes the grease evenly around the bushing circumference.
Resume operation
Start the excavator and resume normal operation. The first few impacts will further distribute the grease into the bushing.
Grease Specification
Standard lithium-based grease (NLGI 2) is NOT suitable for hydraulic breaker chisels. The correct lubricant is a specialized chisel paste — a high-viscosity, high-pressure grease formulated for the extreme impact loads and temperatures in the front head.
Chisel paste is typically dark gray or black in color due to the addition of molybdenum disulfide (MoS2) or graphite, which provide boundary lubrication under extreme pressure. Common specifications include:
- Molybdenum disulfide content: 3–5% - NLGI grade: 1–2 - Base oil viscosity: ISO VG 460–680 - Temperature range: -20°C to +150°C
Most major breaker manufacturers (Epiroc, Furukawa, Montabert, NPK) sell their own branded chisel paste. Third-party alternatives are available, but must meet the above specifications.
Common Greasing Mistakes
These are the most frequent greasing errors that lead to premature wear and costly repairs:
Using the wrong grease
Standard wheel bearing or chassis grease does not have the pressure resistance needed for hydraulic breaker chisels. It will be squeezed out of the bushing within minutes of operation.
Using the wrong grease is equivalent to not greasing at all — the bushing will wear rapidly.
Over-greasing
Applying too much grease (more than 5–6 pumps) can force grease past the back cap seal and into the hydraulic circuit, contaminating the oil and damaging the piston seals.
Greasing with the chisel raised
Greasing with the chisel fully retracted into the front head means the grease is applied to the wrong part of the bushing. Always grease with the chisel in contact with the ground.
Skipping greasing during short breaks
Many operators only grease at the end of the day. If the breaker has been operating for 2+ hours, grease before the next work session — not just at shutdown.
Frequently Asked Questions
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Applies to These Models
This guide is especially relevant for the following hydraulic breaker models.
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The SB10 is a compact mini hydraulic breaker designed for 1–4 ton excavators. Ideal for light demolition, trenching, and confined-space work.
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