The hydraulic system is a very important part of the concrete mixer. If this system fails, it will seriously affect the use function of the concrete mixer.

（1）搅拌车液压系统的压力不足或完全没有压力

(1) Insufficient or no pressure in hydraulic system of mixer truck

产生原因包括：

The causes include:

a.液压油泵油压不够，泵的转速过低，需要检查油泵的动力系统。

a. The oil pressure of the hydraulic oil pump is not enough and the speed of the pump is too low. It is necessary to check the power system of the oil pump.

b.液压油黏度过低，会导致液压系统容积效率降低，也会造成压力上不去，此时需要更换适当黏度的液压油。

b. If the viscosity of the hydraulic oil is too low, the volumetric efficiency of the hydraulic system will be reduced, and the pressure will not go up. At this time, it is necessary to replace the hydraulic oil with appropriate viscosity.

c.溢流阀的工作压力调得低于规定值，则需要按规定重新调好；如造成溢流阀工作时不正常，阀内存在脏物、阀不能关闭，先导阀阀座脱落或弹簧折断而失去作用等，则需要对溢流阀进行清洗，更换或修理。

c. If the working pressure of the relief valve is adjusted lower than the specified value, it needs to be readjusted according to the regulations; if the overflow valve is not working normally, there is dirt in the valve, the valve cannot be closed, the valve seat falls off or the spring breaks off and loses its function, the overflow valve needs to be cleaned, replaced or repaired.

（2）搅拌车流量太小或完全不出油

(2) The flow rate of mixer truck is too small or no oil is produced at all

1）如果泵运转正常，但仍然没有油输出，则可能是以下一些原因造成的。

1) However, if the following causes the pump to still run normally, then it may be caused by no oil output.

a.油箱油面太低

a. The oil level in the oil tank is too low

b.吸油器或吸油滤油器堵塞

b. The oil suction device or oil filter is blocked

c.吸油管路密封不好，吸入空气。

c. The sealing of oil suction pipeline is not good, and air is inhaled.

d.油的黏度太高阻力过大等。

d. The viscosity of oil is too high and the resistance is too large.

排除故障的办法是，应该加油或清洗吸入管路及滤油器，或者更换密封或更换低粘度液压油等。

The way to solve the problem is to add oil or clean the suction pipeline and oil filter, or replace the seal or replace the low viscosity hydraulic oil.

着重指出的是，一旦发现油泵运转但无液压油输出，就应该立即停止油泵的运转，否则泵的内部可能会因缺乏润滑而烧坏，将造成非常严重的后果。

It is emphasized that once the oil pump is found to be running but there is no hydraulic oil output, the operation of the oil pump should be stopped immediately, otherwise the internal part of the pump may be burnt out due to lack of lubrication, which will cause very serious consequences.

2）如果出现油泵虽然有油输出，但流量却不足的现象，则可能是下列原因。

2) If the oil pump has oil output, but the flow is insufficient, it may be due to the following reasons.

a.泵内部的机构磨损导致了内泄，需要更换或修理内部零件。

a. The internal mechanism wear of the pump leads to internal leakage, and the internal parts need to be replaced or repaired.

b.油的粘度过低，以致油的容积效率太低，需要更换适当黏度的液压油。

b. The viscosity of the oil is too low, so that the volumetric efficiency of the oil is too low. It is necessary to replace the hydraulic oil with appropriate viscosity.

c.油泵转向不对或转速过低造成，需要改正泵的转向或检查油泵的动力系统。

c. The steering of the oil pump is not correct or the speed is too low. It is necessary to correct the steering of the pump or check the power system of the oil pump.

（3）搅拌车液压波动或流量脉动

(3) Hydraulic fluctuation or flow pulsation of mixer truck

出现这种现象的原因一般有两种。

There are generally two reasons for this phenomenon.

a.液压油中混入了大量的空气。检查油箱，如有泡沫或气泡，则要更换油箱；其次还要检查和吸油管路中的漏气现象。

a. There is a lot of air in the hydraulic oil. First check the fuel tank, if there is a bubble or bubble, then replace the fuel tank; secondly, check and eliminate the leakage phenomenon in the suction line.

b.溢流阀工作不稳定而产生跳动，引起压力波动或流量的脉动。其原因可能是阀内有脏物堵塞、阀座磨损或调压弹簧损坏等，处理方法是清洗阀件、更换零件或换新。

b. The pressure fluctuation or flow pulsation is caused by the unstable operation of relief valve. The reason may be that the valve is blocked by dirt, the valve seat is worn or the pressure regulating spring is damaged. The treatment method is to clean the valve parts, replace the parts or replace them.

（4）搅拌车严重噪声

(4) Serious noise of mixer truck

产生噪声的原因包括：

The causes of noise include:

a.吸油管路中混入了空气。混入空气的原因可能是油箱油面过低，应该加油规定刻度，保证吸油顺畅；混入空气的 另一种原因，可能是油泵轴的密封漏气或吸油管路接头漏气，应该更换密封或修理、更换接头。

a. Air is mixed in the oil suction line. The reason for air mixing may be that the oil level of the oil tank is too low, so the oil should be filled to the specified scale to ensure smooth oil absorption; another reason for air mixing may be the air leakage of the seal of the oil pump shaft or the air leakage of the oil suction pipe joint, so the seal should be replaced or the joint should be repaired or replaced.

b.油泵吸空时，也可能导致严重噪声。可能是吸油滤油器堵塞或吸油管路堵塞，也可能是油泵转速过高，或者是油的黏度太高或油温太低。对于一种情况，应该清洗滤油器或吸油管路；对于二种情况，应该检查油泵的动力系统；对于一条，则需要更换油液或加热油液。

b. When the oil pump is empty, it may also cause serious noise. It may be that the oil suction filter is blocked or the oil suction pipeline is blocked, or the oil pump speed is too high, or the oil viscosity is too high or the oil temperature is too low. For one case, the oil filter or oil suction pipeline should be cleaned; for two cases, the power system of the oil pump should be checked; for the last one, the oil fluid needs to be changed or heated.

（5）搅拌车操作阀工作时跳动

(5) The operation valve of the mixer truck jumps when it works

操作阀工作时跳动产生的原因包括：

The causes of operation valve runout include:

a.油液太脏，致使滑阀的配合部位有污物、杂质，此时应该拆下并清洗阀件。

a. The oil is too dirty, resulting in dirt and impurities in the fitting part of the slide valve. At this time, the valve should be removed and cleaned.

b.滑阀或滑座表面有伤痕，则需要更换或修理阀座。

b. If the surface of the slide valve or sliding seat is damaged, the valve seat needs to be replaced or repaired.

c.滑阀回位弹簧变形或损坏，需要更换回位弹簧。

c. The return spring of slide valve is deformed or damaged, so it needs to be replaced.

（6）搅拌车油马达不动作或动作不平稳产生原因包括：

(6) The reasons for the failure or instability of the oil motor of the mixer include:

a.油马达中的密封间磨损严重，致使压力腔和回油腔之间产生泄露增加，应更换密封件。

a. The seal in the oil motor is seriously worn, resulting in the increase of leakage between the pressure chamber and the oil return chamber, so the seal should be replaced.

b.油马达内部的高压溢流阀与低压溢流阀设定压差太小，应调整高压溢流阀设定压力与低压溢流阀设定压力。

b. The set pressure difference between the high pressure relief valve and the low pressure relief valve in the oil motor is too small, so the set pressure of the high pressure relief valve and the low pressure relief valve should be adjusted.

c.系统中压力不足或完全无压力、发动机怠速、流量大小或完全不出油以及压力波动或流量脉动等原因所致。

c. It is caused by insufficient or no pressure in the system, idling of engine, flow or no oil, pressure fluctuation or flow pulsation.