How to Deal with It If The Mixing Drum of Self Loading Mixer Cannot Rotate?

In the fields of construction and engineering, self-loading concrete mixers are widely utilized for the process of mixing fresh concrete mixture. However, there are instances during the usage of self-loading concrete mixers where the mixing drum might fail to rotate. The issue can potentially lead to work disruptions and production delays. Here I have explored the potential causes of this common problem and provide solutions, allowing the clients to better understand and address the challenges that can arise with self-loading concrete mixers during construction processes.

self loading concrete mixer working on-site

Common Potential Causes and Provide solutions for Mixing Drum Not Rotating

A list of six points that need to be checked may cause the mixing drum of self loading mixer to not rotate. You need to step by step according to these six steps to find out the reason.

Step 1. Check the hydraulic oil level and oil quality

  • If the hydraulic oil is insufficient, make up the hydraulic oil until the oil level gauge is in the middle position.
  • When the hydraulic oil is dirty, replace the hydraulic oil.

Step 2. Check if the inlet ball valve is closed

If the valve is closed, please open the ball valve and set the the limit bolt.

Inlet Ball Valve of Self Loading Mixer
Inlet Ball Valve

Step 3. Check if the filter is blocked

If it is, replace the filter right now.

Filter of self loading mixer

Step 4. Checking the control connection structure and the flexible shaft

After pushing the pump control handle forward or backward for a certain distance, check whether the control handle on the pump control valve changes the angle accordingly. If there is a corresponding change angle, go to step 5. If the angle is not changed, check the following steps:

  • Check if the pump control shaft is effectively connected to the control handle;
  • Inspect if the flexible shaft seat is fixed firmly on the chassis, and the rigidity is enough;
  • Check if the flexible shaft is firmly connected to the controller and whether the rear end of the flexible shaft is fixed firmly;
  • Checking if the controller is damaged, replace the controller if it is damaged;

Step 5. Check pump control valve

Turn the control valve handle at a small angle to see if the can rotates, If it is rotated, go to step 6. If it does not rotate, check the following steps:

Pump Control Valve
Pump Control Valve
  • Check if the control handle and the valve rotation shaft are firmly connected and rotate together;
  • When removing the control valve assembly from the pump, check whether the linkage mechanism of the control valve is connected with the connecting rod of the servo mechanism. If it is not connected, connect it. If the connecting rod is damaged, replace the connecting rod;
  • Check whether the three control oil holes on the control valve are clean. If there is blockage, flush it with an air gun. At the same time, check whether the control oil hole entering the servo mechanism on the pump body is blocked;
  • Turn the control handle to see if the spool moves normally. If the control handle is moved and the spool does not move, the spool is broken and the controller assembly must be replaced;

Step 6. Check pump charge pressure

  • If the charge oil pressure is normal (18BAR), check the high pressure safety valve, if the high pressure is insufficient, replace the high pressure safety valve;
  • If the charge oil pressure is 0, the pump input shaft or spline is damaged, replace the pump input shaft;
  • If it shows abnormal charge pressure, please check filter.

Generally speaking, following the above six points, you should be able to solve the problem of the mixer drum not rotating. If still not resolved, please contact our engineers for solutions. Contact us through email, tel, and WhatsApp.

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