BTMA—How to repaire and maintain jaw crusher ?

Jaw crushers, like other stone crushers , also need regular repairs and maintenance after working for a certain period of time, otherwise the service life will be reduced due to serious wear of important parts.


What will happen if it is not maintained regularly?



When the jaw plate  wears and tears  so much then it has to be replaced


Therefore, many customers have a common misunderstanding, thinking that the jaw plate needs to be repaired only when there are flats, holes, and cracks. In fact, if the jaw plate is severely worn, it is not only difficult to repair, but also seriously affects the normal work of other parts, so it will cost a lot of money to replace a jaw plate and maintain other parts.


Pittman bearing damage


While the main crushing process is supplemented by the jaws, the key components that move the movable jaws are the switch plates, pitman bearings and flywheels.


The pitman actuates the movable jaw moulds, pushing the stone against the fixed jaws, which creates strong pressure on both jaw moulds. Therefore, if the pitman is not lubricated in time, it will break under the high pressure of the material, interrupting the whole work.



How to check and maintain the jaw crusher correctly?



1、Make a checklist


Reasonable planning and preparation can make the entire repair and maintenance orderly and effective, helping operators save time, cost and improve safety. You can make a list, like the chart below, you can list the jaw crusher parts that need to be checked with different periods, and then make a mark, if you have done it. This not only prevents missed inspections, but also makes arrangements clear and saves a lot of time.


2、Please Do the lubrication work  well


The interface lubrication between the various parts of the jaw crusher is very important. It can minimize the friction generated during operation, make the whole jaw crusher run smoothly and prolong its service life.

Unlike gyratory crushers, the primary lubrication used in jaw crushers is grease rather than oil. When using grease, there may be several different ways of getting it into the necessary lubrication points. It can be a manually operated grease gun, oiler or metering pump.


Which parts need lubrication?


Eccentric shaft (pitman bearing): It is behind the movable jaw, and together with the flywheel, it produces movement with the toggle plate. So, the most important thing you have to do is keep the eccentric shaft regularly lubricated, otherwise when it breaks, you’ll spend over four hours trying to get a new one.


To keep the spindle well lubricated, it is necessary to ensure that there is enough goose between the thrust plates. The grease added to the bearing housing needs to occupy about 50% of its space and be replaced every 3-6 months. When changing the engine oil, use clean gasoline or kerosene to clean the roller bearing raceway.


3、How to maintain and replace the jaw plate?


There are different jaw materials on the market, some are suitable for hard stone and some are not. Therefore, you must choose the proper jaw plate for your crusher. For example, the jaw plate of a general single-twist jaw crusher is not good at crushing hard stones with strong abrasiveness and large output.



It is inevitable that the crusher will wear and tear due to long-term crushing work. All you can do is to do your best to maximize its service life through regular inspections and timely maintenance.


1、 Check whether the tooth peaks match the tooth valleys.


2、Regularly check whether the bolts and nuts are tightened to ensure that they will not loosen during work.


3、Check the jaw surface for flatness, holes, cracks, etc., and if so, adjust or replace it with a new one.


4、If more than 80% of the jaw plate is found to be worn during inspection, in order not to affect the overall performance of the machine, the jaw plate needs to be replaced in time.


5、If you don’t know whether to replace it, you can contact the jaw crusher manufacturer, and they will give you the most professional advice based on the actual situation of the jaw plate.


Inspection and maintenance of other components


Check whether the discharge port is blocked, remove the blockage in time, and keep the discharge port unobstructed.


Check for loose V-belts. If it’s too loose, it needs to be tightened, as the belt will slip if loosened.


Whether the eccentric shaft is blocked. The main reason is that when the eccentric shaft bearing bush is loose, there is no gap on both sides of the frame bearing box. At this time, the bushing should be reinstalled or replaced.


Check whether the position of the flywheel wedge is offset, and correct it in time.



Common problems in jaw crusher maintenance


How to judge that the pitman bearing on the jaw crusher is broken?


  • The internal pollution of the bearing is too high, mainly manifested as the increase of oil and grease. For example, the iron content is higher than 150ppm, the copper content is higher than 200ppm, the silicon dioxide content is higher than 150mmp, and the moisture content is higher than 0.5mmp.


  • The temperature of the bearing is abnormal. Check the swing claw bearing box and the main engine bearing box separately to see if the temperature difference between the two is too large. If the temperature difference is more than 15 – 20of, there must be something wrong with the bearing.


  • There is noise inside the bearing. The noise also indicates a problem with the connecting rod bearings.


How to adjust the toggle plate of the jaw crusher?


The role of the torsion plate is to adjust the outlet of the jaw crusher to the required size. There are two specific methods: one is to replace the support pad between the toggle plate and the body frame, and the other is to adjust two wedges between the toggle plate and the body frame.

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