The common undercarriage fault of a small tonnage crawler crane is the roller oil leakage. It is mainly caused by the loose floating seal ring. While for the large tonnage crawler crane, walking noise and premature wear of track plates are fairly common. Next, we will analyze the 5 most common faults of crawler crane undercarriage parts in detail.

1. Oil Leakage of Small Tonnage Crawler Crane Track Rollers

As we all know, the roller body needs oil lubrication to ensure its smooth rotation. Once there is oil leakage, the roller can not continue to work. Here are the causes of oil leakage:

Defect of The Seal Ring

In the production process, the casting of undercarriage parts matching parts may have defects like porosity, slag inclusion, etc. The machining accuracy of the floating seal ring fails to meet the standard requirements. All of these will lead to the problem of oil leakage when the rollers overload.

Poor Production Environment

Some manufacturers’ assembly workshop conditions are relatively simple. All kinds of wheel parts that originally need strict cleaning are stacked on the ground at will. What’s worse, there is no strict measure for cleaning the rollers during the assembly process. Along with lacking professional assembly tools when assembling the sealing ring. All of those are likely to cause oil leakage of the track roller or carrier roller in the future running.

Lack of Rigorous Product Testing

Some manufacturers lack a strict testing process, just through a simple pressure seal test to add lubricant to the wheel. However, a good supplier always performs a pressure test on the wheel first, draws out the vacuum in the wheel body, and then fills it with oil. The latter can guarantee the product’s sealing better than the former.

In comparison, the professional OEM manufacturers have advanced integrated assembly workshop. Their processing environment is clean and standard, and the products 100% reach the professional standard. Naturally, their Chassis parts have higher overall quality and better sealing. Once the rollers leak, the quick measure to take is to replace it directly. If not, it may cause more serious wear of other chassis parts. It is also recommended that you choose a professional manufacturer when purchasing crawler crane rollers. High-quality wheels are durable with a low failure rate.

Image: Engineersdaily

2. Crawler Crane Undercarriage Parts Abnormal Noise

This problem mainly happens in large tonnage. The reasons are as follows:

• Dry friction between track shoe pin shaft and track shoe pinhole due to insufficient lubrication. Some crawler cranes make abnormal noise in the traveling mechanism after a period of use. This problem is mainly due to the lack of lubrication in track shoe pin shaft. The solution is to spray the track pin shaft at the joint with lubricant, such as gear oil.
• Track plate pinhole concentricity deviation. Track shoes for large tonnage crawler crane commonly have features of large volume and long length. Many manufacturers fail to deal with the problem of thermal deformation in the heat treatment after the casting. Eventually, the coaxiality deviation of the pinhole of the crawler plate is likely to appear. That means the hole and the shaft will not fit well.
• Improper chassis tension. The tension degree of track shoes is inappropriate, either too loose or too tight may cause abnormal noise and premature wear of track shoes and wheels.

If the noise is caused by the concentricity deviation of the pinhole of track shoe, you should contact with the parts supplier to apply for a qualified accessory. (Note, choosing a reliable supplier with strict quality control will help minimize such parts failure). If there is something wrong with the track tensioner, adjust it to avoid more serious wear happening.

3. Severe Friction between Sprocket and Crawler Plate

The tracks shoes and the whole machine are connected in a floating way, the crawler crane track shoes will be floating when the machine moves. It is inevitable that there will be sliding friction and extrusion between the track shoe and the driving wheel, so slight wear is a normal phenomenon.

But, it should be noted that the improper meshing between the driving wheel and the track shoe will cause severe friction. The specific performance is that the edge of the track shoe is seriously worn, and the teeth of the driving wheel are dented. This is mainly related to the maker lacking strict control over product accuracy. Details are as follows:

• In the design, because the manufacturer does not consider the casting error fully, the pitch matching between the track shoe and the driving wheel is not reasonable. The accumulated error may cause serious wear when the track shoe and the driving wheel mesh.
• If the manufacturer’s casting process level is too poor, and they fail to control the dimensional tolerance of the track shoe pin bore, it will lead to the pitch deviation. As a result, the track shoes can not match the driving wheels properly.
• The tightness of the track plate is not appropriate, too loose or too tight may lead to the occurrence of bad meshing problems.

Concerning the above problems, we have mastered how to control the accuracy of the track shoes in the design after a long-time groping test.

The serious friction between the driving wheel and the crawler crane track shoe has a lot to do with the unqualified manufacturing process of the manufacturer. To tackle the problem at the source, owners should purchase from professional and reliable OEM crawler crane parts manufacturers. In this way, not only the product quality is guaranteed, but also you will get a perfect after-sales service.

4. Crawler Crane Chassis Reducer Bolts Loose

When the machine turns, it needs to output a lot of torque, and what can balance the torque is the pre tightening force of the reducer bolts. There are 3 main reasons for chassis reducer bolts loose. In general, lacking bolt pre tightening force is the immediate cause.

• The pretension required to be applied to the bolt is not enough;
• Due to the quality and material problem of bolts and washers, the preload of bolts cannot be applied at full load;
• The machining accuracy of the mounting surface of the walking reducer and bolt washer is poor, the joint surface cannot meet enough preload require.

Manufacturers should practice factory test on the strength of washers and bolts, and strictly control the processing accuracy of products. These are also what crawler crane owners should pay attention to when purchasing undercarriage parts.

If the bolt is loose due to insufficient preload, you need to tighten it according to the operating instructions; If it is caused by the quality defect of bolt or gasket, contact with your supplier for a new one.

5. Wear Between Track Shoe And Frame Structure

There are several reasons for this problem:

• The track shoes are too loose, it will wear the corresponding structural parts when walking.
• There is serious wear and tear on the top roller, if we can not replace it in time, the track shoes may get loose. And the crawler crane track shoes and the track frame structure also could interfere with each other. Therefore, it is necessary to replace the worn parts in time to avoid more serious and difficult consequences.
• If this kind of wear occurs at the upper and lower parts of the front and rear ends of the track frame, there must be something wrong with structural transition treatment.

Periodically adjust the track tensioner, check the height of the top roller to see if there is serious wear and tear if so, replace it in time. If there is some flaw with the transition of the crawler frame structure, be sure to contact the manufacturer to apply for technical support.

Maintenance of crawler crane should be comprehensive, only in this way, it can serve you for a longer time. If you have any questions or any different experience with crawler crane undercarriage parts! Do let me know. Looking forward to your comment.

Read: 6 Tips on How to Dismantle The Crawler Crane Parts Booms Safely

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