Hydraulic jacks are used to perform work associated with raising to a certain height of various objects. They may differ in terms of capacity, type, purpose, but the device and the principle of operation are the same, which means that the malfunctions of the hydraulic jack will be similar.
Hydraulic jacks are used to lift heavy objects during their repair.
The device and principle of operation of the hydraulic jack
In order to better understand why the breakdown occurred and what is the reason for it, you should know how the hydraulic jack works and how it works.
The device and principle of operation of the hydraulic jack.
The device of the jack is quite simple: a body made of hardened metal, a rod (or a retractable piston) and a working fluid - oil. The body serves not only its intended purpose, but is also a full-fledged working part of the jack - it is a fluid reservoir and a guide cylinder for the rod. Depending on the model, control is exercised by means of a pump with a manual, air or foot drive.
Works jack on the principle of communicating vessels. Those. due to the fact that the pumped oil from the pump enters the cylinder, the sliding valve is squeezed out and, accordingly, the weight is raised to a height, and in order to return it to its original position and lower the load, the ejection valve opens and the liquid flows back. Some hydraulic jacks have built-in pressure gauges to control operating pressure.Back to table of contents
The main causes of faults hydraulic jack and how to eliminate them
Jack repair scheme.
One of the most common causes of a jack breakage can be oil leakage. As a result, air enters the working chamber, as a result, the lifting mechanism does not work at full strength or ceases to function.
This problem can be avoided by periodically servicing the hydraulic jack, which consists in controlling the amount of fluid, and, if necessary, topping up it into the working cylinder. Reducing the amount of oil in the system can be a consequence of natural operational loss, as well as due to damaged or faulty oil seals and seals. In this case, the usual topping up the liquid will not solve the problem, it will be necessary to replace the failed seals and seals.
Due to the lack of working fluid in the system, air takes its place - this can be guessed by the decreased performance of the jack. You can get rid of this problem by performing pumping. To do this, open the stopper of the oil tank and the relief valve and bleed the hydraulic pump. If there is a malfunction in this, then, provided that this work is done correctly, the jack will again be in working condition. But if this did not help, then the cause of the malfunction is different, or more serious repairs will be required. Sometimes this problem can be solved by turning the locking needle back two turns, at the same time raising the piston to the top point, and then releasing it so that it reaches the bottom. This action must be repeated 2-4 times.
Upon detection of corrosion and damage to parts replace them.
Often the cause of improper operation of the hydraulic jack can be corrosion, affecting the retractable pistons (rods or plungers) and the inside of the housing. But to find out the reason, you need to disassemble the device. To do this, you can contact the service workshops or do the work yourself. You will need a set of keys, a repair kit, a container for draining old oil and a canister with a new one for filling into the system after repair.
A curved rod also often becomes the cause of a jack failure, in this case, if it is provided for by the design features of the model, it can be replaced with a new one, and often this means that the jack cannot be repaired even in the conditions of a service workshop.
Sometimes dirt gets into the working chamber, which can also cause the jack to fail.
It is possible to remove dirt by washing it with kerosene. An overflow valve can also often be the culprit. It can have some deformation, or dirt has got into it, which leads to the fact that the ball is not tightly in the saddle and, therefore, there is a leakage of fluid. This problem is solved basically radically - by replacing the bypass valve.Back to table of contents
Some indications of malfunctioning hydraulic jack
If the jack lifted the load, but gradually spontaneously lowered, then in this case the reason should be sought in the relief valve or cuffs.
The jack lifted the load to the desired height, but is unable to hold it, there is a gradual spontaneous lowering - in this case the reason can be found in the overflow valve or broken cuffs. Because of this, the required pressure is not maintained.
In cases where it is not possible to lift the load with a hydraulic jack or it lifts it only to a small height, this indicates a decrease in the working stroke. The reason in this case lies in the appeared corrosion on the rod and on the inside of the cylinder body. And if a jack lifted a load that exceeded the maximum permissible mass for this device by mass, a stem curvature may have occurred.
The springs that have been stretched or have lost their elasticity can be guessed by the fact that the jack does not return fully to its original position after opening the release valve.Back to table of contents
Disassembly of hydraulic jack and oil change
Of course, it is safer to repair a faulty hydraulic jack in the workshop, but in some cases it is quite possible to do this work and independently, for example, to pump or add / change oil in the working system. You should only know how to properly disassemble, and then assemble it. Basically, any type of jack repair occurs in the same way: first you need to unscrew the fasteners and remove the bleed valve and piston, drain the oil. After that, eliminate the malfunction and assemble the jack by performing all actions in the reverse order, replacing all the failed parts and pouring in new oil. After this, a test monitoring of the jack working capacity is carried out.
The oil change in the jack can be made independently, without using the services of the service.
If a serious malfunction with your own hands can be difficult or even impossible, then replacing the oil in the jack is quite possible. The main thing is to observe the sequence and correctness of actions. First, all fluid is drained from the hydraulic jack and is cleaned using a special flushing fluid. Sometimes one washing may not be enough - then it is repeated. During the flushing of the jack should be pumped, so you can achieve the maximum effect of this procedure.
Flushing fluid, like old oil, should be completely removed from the jack and only after that you can pour new fluid. Capacity for it should be filled to the appropriate mark, while it is necessary to ensure that the jack is in the "lower position". Then, pumping is performed at least 5 times and the oil is added to the required level. After pumping is performed again and so many times until the oil level reaches the desired level, one of the characteristic signs of this is the absence of bubbles on the surface of the oil.
It is recommended to carry out operations for changing the oil in a jack that is regularly used once every 1-3 months, depending on the intensity of the loads. There are no special requirements for the type of oil, but experts advise to use its synthetic types for working in cold conditions.