When we buy a new hydraulic motor for our excavator, we need to connect it to the rest of the hydraulic system in the right way. A properly functioning hydraulic system ensures efficient and faultless operation over a long period of time. If we do not follow the manufacturer’s recommendations on the installation of individual hydraulic lines, for example, we can easily damage the hydromotor. Why is it so important to connect the hydromotor correctly? What is the function of the drain line? What consequences can a wrong hydromotor connection have? You can find out by reading the following text. Read it carefully!
The hydraulic motor (hydromotor) is an essential component of every excavator. The correct connection of the hydromotor guarantees the safe and efficient operation of construction machinery and its components, such as excavator final drives. In addition, connecting the individual components of the hydraulic system in accordance with the manufacturer’s recommendations prevents serious failures.
Most modern final drives have either 4 hydraulic hoses (2 for forward/rear travel, drain hose, fast travel hose) or 3 hoses (2 for forward/rear travel and drain hose). However, some excavators, usually older models, have an extra hose leading to the brake and even a hose responsible for the track tension). You should certainly check with your dealer at the outset what function the other hoses have if there are more than 4. We will deal here with the most common solution when an excavator has 4 hydraulic hoses.
Before you start installing the hydromotor, make sure that the hydraulic system is not dirty, i.e. that there are no residues of grease, oil or other substances on the individual components you will be connecting. The hydraulic system should be clean.
The first thing we should look at is the condition of the working fluid. In most cases, this will be hydraulic oil. Let’s check what colour it is and whether it is contaminated. Contamination of the hydraulic fluid may have occurred, for example, as a result of a broken hydraulic cylinder seal.
It is strongly recommended that all the hydraulic oil in the excavator is replaced, along with cleaning (flushing) the hydraulic system and the hydraulic oil tank. In addition, the replacement of all hydraulic filters is also required – here you should find out from your machine dealer how many hydraulic filters there are in the excavator’s system.
Connecting the hydraulic lines to the hydromotor correctly, is not a difficult task, as long as we follow a few important rules. Firstly, we need to carry out an identification of the hydraulic hoses. The hoses feeding the hydraulic motor are generally the thickest, and we should have no problem identifying them. They are responsible for moving the excavator back and forth.
The next step is to connect the hose responsible for the operation of the second gear. If you have trouble identifying it correctly, place the still unconnected hoses in a container, fire up the machine and engage the second gear. If liquid starts to come out of any of them, this will indicate that it is the hose you are looking for. It should be connected to the two speed port. The hose from which no oil comes out is the drain (return) line. Connect it to the case drain port.
It is important to remember that even when we buy an original new final drive for our excavator, it may be manufactured to newer technology and the hydraulic ports may be different or in a different location. The ports will have the same functions but may be in a different location.
In addition, the new travel motor should not be connected in the same way as the old one was. This is a very common mistake encountered both when the hydromotor is installed by a person who has encountered this issue for the first time and by an experienced mechanic.
It is mandatory to read the connection instructions and, if in any doubt, consult the drive supplier. Even short-term operation with incorrectly hydraulic connections can damage the hydromotor and cause further machine downtime and additional costs.
Care must be taken when connecting individual hydraulic hoses to the engine. If the hydraulic lines, e.g. the return and second gear lines, are incorrectly connected, a situation will occur in which the oil has no outlet to the tank and the pressure in the engine will build up. The consequence of such an occurrence can be permanent failure of the hydromotor. The arrangement of the connections of the individual lines may vary depending on the model of the travel motor.
Proper connection of the hydromotor of the final drive ensures adequate lubrication of the hydraulic system. It protects the system from seizing during operation. The oil used for this must be drained through a special line (excess line) back to the tank. If a blockage were to occur behind the case drain ports and the oil could not return freely to the tank, this could cause serious damage to the hydraulic system.
When we want to connect a hydraulic motor on an excavator, there are a few important rules to follow. The most important thing is that each hydraulic hose is connected to the correct port. Connecting the hoses incorrectly can expose our company to downtime and costly repairs. So if we are not certain how to connect the hydromotor correctly, we should first consult someone experienced or have the installation done by a professional.
