How to solve the problem of Doosan excavator turning to the right slowly and unable to brake

 Applicable models: All models Phenomenon: The turning speed and braking to the left are normal, but the turning speed to the right is slow and the car cannot be braked.

1. Inspection essentials: 

  A. The one-way rotation is normal to eliminate the problem of the main pump. 

  B. Check the pressure during rotation overflow, which is 285BAR to the left and 190BAR to the right,

 which is lower than the standard value of 280BAR.  

C. Adjusting the left and right rotation relief valve has no effect, indicating that it has nothing to do 

with the relief valve. 

  D. Check the oil supply one-way valve on the right side of the rotary motor and find that the one-way

 valve is stuck in the normal position. Take out the one-way valve and grind it. After installation and 

test run, it is normal.

2023.07 Doosan DMS-5 Data Monitoring System Diagnostic Software 

 2. Cause: The one-way valve is stuck in the normal position, causing a large amount of hydraulic oil 

leakage in the right chamber, resulting in low pressure and slow speed. 

  3. Treatment method: Take out the stuck one-way valve and grind it, OK

 2020 Doosan Daewoo Excavator Operation and Repair Manual PDF