The ultimate buying guide on hydraulic breaker hammer

This article is a complete guide for everything you need to know about hydraulic breaker hammers.

It will cover everything from the structure, components, and working principles to tips for purchasing, maintaining and repairing a hydraulic breaker hammer.

We will also include a FAQ and troubleshooting guide that covers every detail you need to know.

The Auther work with teams with over 20 years of industrial experience and would like to share the knowledge with people in the field for free.

It helps both beginners and professionals to have a better understanding of hydraulic breaker hammers.

Among the key subjects, the “Ultimate Buying Guide of Hydraulic Hammers” includes six chapters.

Definition of hydraulic breaker hammer. A brief introduction of its history and an overview of types and applications.

Hydraulic breaker structure. This section covers major components and provides a general sketch of the structure.

Hydraulic breaker working principles. An informative chapter with charts and videos to explain the technical principles of operating a hydraulic hammer.

How to select hydraulic hammers. Six most practical tips are offered for choosing the right hammer; this section is intended to offer general suggestions in the form of a buying guide.

Hydraulic hammer maintenance guide. Most common maintenance suggestions and video guidance. A complete pdf maintenance guide is for download.

The FAQ about hydraulic breakers. A list of FAQs about daily use, repairing, maintenance, and troubleshooting—all the details you need to know!

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What is a hydraulic breaker hammer?

The hydraulic breaker hammer is a type of heavy construction machinery that is mounted on excavators, backhoes, skid steers, mini-excavators, and stationary plants.

Driven by hydraulic power it breaks rocks into smaller sizes or demolishes concrete structures into manageable pieces.

They are so versatile tools that can handle a wide range of jobs, with different sizes and models to suit particular needs.

A good hammer is built to last, commonly used in various applications like demolition, construction, road building, mining and quarrying, tunneling, and landscaping.

rock breakers application
rock breaker applications

Hydraulic Breaker hammer Structure

In order to understand how a hydraulic breaker hammer works, or what hydraulic hammer working principle is, the structure and major components need to be clarified first.

A hydraulic breaker hammer consists of three major parts: back head (nitrogen chamber), cylinder assembly, and front head. 

We’ll come to them separately.

hydraulic hammer structure

1. Back Head (Nitrogen Chamber)

The back head is a chamber for storing nitrogen.

When placed under high pressure, this nitrogen-filled chamber acts like a damper upon the return piston-stroke.

It also works like an impact enhancer when the piston travels down.

hydraulic jack hammer

2. Cylinder Assembly

The cylinder assembly is the core part of a hydraulic breaker hammer.

It mainly consists of a cylinder, a piston, and a control valve.

The piston and the valve are the only two moving parts of a hydraulic breaker hammer.

The piston moves up and down and hits on the tool, while the valve rotates to control the oil flow’s direction.

It is the place where movement happens and where the hydraulic power is generated.

With the main valve controlling the oil, the hydraulic flow drives the piston movement to generate impact energy.

A set of seal kits are put inside the cylinder to prevent oil leakage.

breaker hammer structure

3. Front Head

This is where the piston connects with the chisel (or working tool).

The chisel is fixed with bushes and pins, which are the parts that need to be replaced most frequently.

The front head touches the working surface directly, and a box-type housing could protect it from wearing and lead to longer service life.

front head

Besides the 3 major components, a hammer also consists of dozens of accessories.

Hydraulic Breaker Hammer Working Principle

Now comes the killer part.

This chapter contains a lot of great technical information.

If you have an engineering background, this section will help you understand the technical aspects of how a hydraulic hammer works and operates.

If you think these flow charts are tedious and tough to understand, you can move straight to the conclusion.

As stated in the last chapter, with the main valve controlling the flow of oil in and out, the hydraulic flow drives piston moves up and down, and generate impact energy.

In this chapter, four flow charts are going to be used to clarify the whole process.

Remarks 

  • 1-8 means chambers of oil flow
  • Red areas are full of high-pressure oil flow
  • Blue areas are full of low-pressure oil flow
  • Chambers 3, 7 always have low pressure because they connect to “out”
  • Chambers 1, 8 always have high pressure because they connect to “in”
  • The pressure in chambers 2, 4, 6 changes with piston movement
  1. High-pressure oil enters and fills chamber 1 and 8, acting on the piston end-face and pushing it upward.

hydraulic breaker working principle 1

2. When the piston moves upward towards its limit, chamber 1 and 2 get connected and oil flows from chamber 2 to 6.

The control valve moves upward due to the difference in pressure (oil pressure in chamber 6 is higher than in 8).

hydraulic breaker working principle 1

3. When the control valve reaches its upper limit, the input hole connects to oil flow in chamber 8, which makes oil flow into chamber 4.

Owing to the high oil pressure of chamber 4, together with nitrogen backups, the piston travels down.

hydraulic breaker working principle 1

4. When the piston travels down and hits the chisel, chamber 3 and 2 get connected, and they both connect to chamber 6.

Because of the high oil pressure in chamber 8, the control valve travels down and the input hole connects to chamber 7 again.

Then a new circulation begins.

hydraulic breaker working principle 1

Conclusion

One sentence is enough to sum up the hydraulic hammer working principle: “The relative position change of piston and valve, which is driven by oil flow going “in” and “out,” transforms hydraulic power into impact energy.”

Watch the short video for a thorough explanation.

How to choose a hydraulic breaker hammer?

Now you know what the hydraulic breaker is, and you intend to buy one.

A hydraulic breaker is not a small investment, nor is it built for an easy life.

Selecting the right hammer could save a lot of money in the long run and boost your efficiency.

We summarize six most practical tips to explain “how to choose a proper hydraulic breaker hammer”.

1. Size

A hydraulic breaker hammer must mount with the right size carrier. The proper match can optimize efficiency while protecting your valuable investment.

Since there is no universal industrial standard, the size of the breaker can be measured by weight ratio, impact energy level, chisel/piston diameter, etc.

Each has its own merits, and I take piston/chisel diameter most into consideration.

In short, bigger tools & chisels normally lead to a higher power and lower frequency. The breakers are mounted with heavier carriers.

For instance, a hammer with 140mm tool diameter is a good match to a 20-ton class, like Cat 320c, Komatsu pc200 excavator.

And a 45mm chisel diameter breaker is a good fit to your 2-ton Bobcat skid steer or a 1.8 ton Kubota mini excavator.

breaker chisels

2. Project & application

The hydraulic hammer is versatile enough to work in various applications, so it is critical to match your machines with the intended project.

In mining or quarrying, impact power counts most, which may require a larger hammer with a slower rate in order to break up rocks or limestone into small pieces.

When it comes to road demolition or tunneling,  penetrating power and impact rate is the key factor to improve efficiency. A medium size hammer for 10-ton class is a good option.

For post hole digging or landscaping, a skid steer or mini excavator mounted with a 1-ton class breaker works best.

It is your choice to use a 30-ton class heavy duty hammer on road demolition, but it is a waste in my opinion.

3. Proper hydraulic flow

Hydraulic breakers are driven and powered by the hydraulic flow of excavators. Some can adapt to a wide range of flow, while some can not.

Overflow will damage the hammer due to the extra pressure. While without sufficient flow, the hammer will become slow, weak, and unproductive.

In principle, the wider range means better universality while narrow-flow breakers bring more productivity.

For instance, the Cat 130H hydraulic breaker hammer (129.5mm tool diameter, 18-36 ton excavator class) adapts to the flow range 120-220 l/min.

And its best match fluctuates around 20-ton class; this is best suited to road building and construction.

No doubt it could work under higher oil flow and heavier duty carriers (which means more comprehensive applications, like mining and quarrying),

It might not be a perfect option.

A new hammer with a bigger piston and tool diameter might work better in this case.

For instance, a heavier hydraulic hammer of 155mm diameter chisel and piston is more powerful and productive on a quarry plant.

So do you select one hammer for better universality or several for the best flow match? That’s your call.

4. Type of housing

There are three types of shells or housings for a rock breaker, and each has its own features.

3 types of rock breakers

Choose a box type, or silenced type, to make the most use of it, not just for keeping noise level down.

The full closed housing made of thickened wear-resistant steel plates will protect the main body and front head from wearing and impacting.

Rock breakers do not have an easy life, and better protection will extend service life, which in turn protects your investment.

hydraulic breakers structure

box type wear-resistance housing

5. Maintenance cost

When choosing a hydraulic breaker, maintenance cost is a long-term expense to take into account.

Hydraulic breaker maintenance costs money, and it deserves every dollar you invest in it.

It happens when parts are worn out and need to be replaced regularly.

Ask your dealer or service center for the retail price of pins, bushes, chisels and seals kits, as well as the time interval for replacement.

Then estimate a budget you would like to pay for it.

Regular and proper maintenance to your hydraulic breaker guarantees working efficiency and long service life.

rock breaker parts

6. Used & rebuilt hydraulic hammer

A hydraulic hammer is not a toy and usually work under tough circumstances.

Occasionally it requires rebuilt.

It is true that a hammer could be rebuilt, also a good way to make it work longer.

But it might be an issue when it comes to purchasing a used or rebuilt one.

You never know if the piston is damaged or if the cylinder is scratched just by looking at it.

It might occur that the seal kits damage after one week, or oil leakage because the cylinder gets rust.

Buying an unqualified rebuilt hydraulic breaker hammer may seem cheap first, but it may cost thousands of dollars after months of use.

Make sure you are buying a used or rebuilt hydraulic hammer from a trustworthy rebuilt center.

Or just buy a new one.

Hydraulic hammer maintenance guide

Proper maintenance and regular parts replacement can lead your hydraulic hammer to better performance.

And a key factor to make its long service life.

To get an overview of it, we sum up the most common maintenance suggestions to clear your daily confusion.

Greasing

Proper lubrication is critical to extending the life of your rock breaker.

We recommend greasing your hammer every two hours of use.

Failure to grease regularly will significantly increase wear rates and reduce the lifespan of your tool, bushings, and front head components.

Storage

A hydraulic breaker hammer can be stored either vertically or horizontally. For long term storage, keep it standing up would be a better option.

This will allow the breaker’s weight to push the tool and piston up inside the breaker.

If you leave them on their sides for a long time, all the seals have to support heavy internal pieces like the piston.

O-rings and backing rings aren’t meant to be load bearing.

Nitrogen check & Nitrogen charging

Click the link below for a step-by-step video guide.

FAQ & Troubleshooting Guide

1. What factors affect a hydraulic hammers power?

 The power of the hydraulic hammer is affected mainly by three factors: nitrogen pressure (back head pressure), hydraulic flow, and impact rate.

The amount of nitrogen is very specific; overcharging the nitrogen will make it stop hammering, while low nitrogen pressure results in weak hammering.

Hydraulic flow directly affects working pressure. Over-flow can damage the hammer very quickly, so be sure to work within the proper hydraulic range.

There is a frequency valve on the cylinder body responsible for the impact rate. Adjust it manually according to working conditions.

Basically, under certain working conditions, a slower impact rate leads to a more powerful impact, and higher frequency means a lighter blow.

2. How often does the seal kit need to be replaced?

It depends on working conditions, makes, and age. We recommend every three months.

3. Can a broken piston be repaired?

 No, a broken hydraulic hammer piston can never be fixed or chrome plated. Close tolerances and impact energy make it impossible. It could damage your cylinder and cost thousands of dollars in the long run.

4. What are the common reasons for piston damage?

Contaminated oil, over-worn inner bushings, and lack of greasing could lead to piston damage. Keep in mind a piston cannot be repaired, so be sure to change out your damaged piston right away.

5. Can the hydraulic breaker cylinder be repaired?

Yes, normal scratches can be fixed and polished, but only once! This is because the carburized layer thickness is about 1.5-1.7mm after heat treatment, so after polishing it still has around 1mm, and the surface hardness is still guaranteed. This repair is only possible for the first time.

6. Why does the hydraulic hammer suddenly stop hammering?

  • Backhead pressure is too high. Release nitrogen and recharge as specified.
  • The backhead is filled with oil. Disassemble the back head and replace the seal.
  • The control valve stuck. Disassemble and clean the valve, replace the worn valve.
  • Oil flow is not sufficient. Repair pump, adjust the hammer valve.

7. Why is impact so weak? 

  • Back pressure is too low. Check back pressure and recharge as needed.
  • Oil is contaminated. Change hydraulic oil and filters.
  • Operating pressure is low. Check the pump and pressure relief valve.
  • Return line back pressure is too high. Check filter and hose connections.
  • The working tool is not fully engaged. Use correct down pressure. Be sure the steel and front cover is not worn and have been properly greased.

 8. Why is the hydraulic hammer not working after installation? 

  • Improper bushing replacement. Refit the inner bushing. Make sure to use the original.
  • Quick couplers are installed wrong. Check connectors and replace as needed.
  • Supply hoses have been reversed. The pressure line from the pump must be connected to port marked IN. The return line connects to port marked OUT.
  • Nitrogen pressure is too high. Release nitrogen and recharge as needed.
  • The stop valve is closed. Open the stop valve.

9. Why is blank firing prohibited for hydraulic hammers? 

When the tool is not in contact with the working surface, hammering the piston is called “blank firing”.

This causes serious damage to the hydraulic hammer body. Pins and bolts may crack, and the front head might break due to the extreme impacting energy.

Any questions about hydraulic hammers? Request purchasing tips from a pro? Leave your message and we will offer a solid solution according to your request!