How to Solve the Problem of Black Smoke From the Doosan Excavator X120 Engine

 This article mainly introduces how to solve the problem of black smoke from the Doosan excavator X120 engine.

 

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                                             Fault description

  1. The engine has obvious black smoke when under heavy load. 2. There

 are no alarms or fault codes on the instrument panel  

 

 

Failure cause analysis  

1. Check whether the air filter element, oil-water separator, and fuel 

 

                   fine filter have exceeded the maintenance period or are dirty and need to be maintained in 

 

  advance. 

                2. Since there is no fault code, it is basically judged to be a mechanical failure, and 

 

                   the cylinder cutoff test is carried out by cutting off the oil (a special high-pressure common

 rail plug is required) 

 3. When the fuel injector of the 2nd cylinder is cut off, the black 

 

smoke is significantly reduced, so it can be judged that the 2nd cylinder injector is faulty. 

 

                  4.  After replacing the 2-cylinder injector, the equipment operates normally.  

 

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in conclusion 

 1. Due to the abnormal wear of the 2-cylinder injector, the fuel injection volume becomes 

larger, the atomization is poor, the combustion is insufficient, and the engine emits black smoke.

 

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How to Solve the Problem of Doosan Excavator Turning to the Right Slowly and Unable to Brake

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

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 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.

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 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

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How to Deal with The Oil Leakage Problem of Doosan Excavator Cylinder Oil Seal

How to deal with the oil leakage problem of doosanDH220LC-V excavator cylinder oil seal

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Applicable to all models 

  Phenomenon: The oil seal of the hydraulic cylinder leaks oil and causes serious pollution. 

1. Inspection essentials: disassemble and inspect the oil seal of the cylinder and analyze the damage of the oil seal:  

 A The oil seal is blackened, loses elasticity, and is severely carbonized. 

 

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  B. The oil seal has one or several scratches, and oil leaks from the scratches. 

  C. The oil seal circumference is damaged in a large area, and the cylinder rod is seriously scratched.

 

 

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2. Reason A. The air in the cylinder is not evacuated before operation, and high temperature is generated under the action of high pressure, resulting in carbonization of the oil seal. 

  B. There are debris particles in the cylinder, which will scratch the oil seal and cylinder rod.

  C. The oil seal is damaged due to severe scratches on the cylinder rod.

3·Processing method: 

  A. Replace the oil seal; avoid violent and large-scale operations before the oil cylinder moves, and try to exhaust the air in the cylinder rod as much as possible. 

  B. Replace the oil seal with a new one to ensure the quality of the hydraulic oil and keep the hydraulic system clean. 

  C. Replace the scratched cylinder rod and oil seal.

    

How to Solve the Problem of Doosan Excavator Traveling Motor Not Moving

 Doosan Excavator DH220LC-V walking motor has no action  

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A  Phenomenon:

 1 There is no movement when walking on the right side, but the 1st and 2nd speeds of walking on  

 the    left side are normal;  

 

 

2  Other actions are normal. 

 

3 The idle pressure for right walking is 38 kg, the pressure during movement is about 60 kg, and the pressure for other movements is normal. 

 

     

 

 

 

 B  Inspection essentials: 

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  1. Check the pilot oil pressure; 

  2. Check whether the main valve core is stuck; 

  3. Whether the rear pump is damaged; 

  4. Is there any abnormality in the traveling straight valve core? 

  5. Check whether the CTS one-way valve is damaged; 

  6. Whether the motor relief valve is damaged; 

  7. Check whether there is any damage inside the motor; 

 

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  C  reasons:  

   The central shaft spring snap ring inside the walking motor falls off 

  D Processing method: Replace the spring circlip and reinstall the traveling motor OK

How to Deal with The Problem of The Whole Machine Shaking When the Doosan Excavator Rotates and The Bucket Arm Works

 How to deal with the problem of the whole machine shaking when the doosanDH220LC-V excavator rotates and the bucket arm works  

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1. Inspection method:  

   A. First analyze whether the cause of the jitter is mechanical jitter or hydraulic jitter. The mechanical 

cause is mainly the jitter caused by the internal breakage of the rotary reducer or the oil cylinder. After 

checking that the parts are normal and have no damage, mechanical jitter can be ruled out. Normally, 

the negative control pressure is measured during rotation and stick action. The pressure during wide-

center action is 6 BAR. The neutral pressure is 40 BAR. Normal.  

 

B·Check that the overflow pressure during rotation is 285 BAR and the bucket arm overflow pressure is 332 BAR. 

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  C. According to the analysis, because two actions vibrate at the same time, it can be basically 

concluded that the problem lies in the main pump. Damage to the pump's plunger, sliding shoe, etc. 

will 

cause the actions associated with the pump to vibrate, and some actions do not feel right. obvious. 

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 2. Reason: After dismantling and inspecting the main pump, a crack in the sliding shoe was found, 

       which caused excessive leakage of the plunger and caused working jitter. 

 

 3·Processing method: Clean the main pump and replace the corresponding accessories OK

How to Deal With the Problem That the Rollers on The Doosan Excavator Do Not Rotate and The Parts in Contact With the Tracks Are Abnormally Worn.

 How to deal with the problem that the rollers on the doosan DH55-5 excavator do not rotate and the parts in contact with the tracks are abnormally worn. 

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  A. Inspection essentials  

1.Construction environment Swamps, water conservancy projects, dredging and other construction sites are relatively soft environments.  

2.Fault situation a. The upper roller hub does not rotate and the contact position with the crawler track is abnormally worn. b. The failure occurred again within a short period of time after replacing the rollers.  

3. Determine the fault During the inspection, it was found that the construction environment of the equipment was soft, and the chassis parts were basically covered by soft soil or attachments, causing the rollers to be unable to rotate normally due to large external forces during operation.  

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B. Reason: The construction environment is soft, and the chassis parts are basically covered by soft soil or attachments, causing the supporting wheels to be unable to rotate normally due to large external forces during operation. 

  C. Treatment method: During construction, clean the attachments on the chassis in time.

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How to Dismantle Doosan Excavator Pump

How to dismantle Doosan  DX 60-9C excavator pump

 Disassembly of the plunger pumps and the gear pumps

1. Remove the bolts (M1025L: 2), because the decomposition plunger pump and gear pump have O-ring on the joint surface, please be careful when separating.

· Tool: 8mm (factory —)

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 Figure  30

 2. Remove the coupling spline sleeve.

   

  Figure  31

 Disassemble the plunger pump

1. Remove the inner hexagon bolt (33,34) and separate the pump from the housing

End cover (21).

(M1230:3) (M1255:1)

· Tool: 10mm (factory —)

  

2. When removing the end cover, please separate in the horizontal direction. When the b is difficult to remove, please tap it gently with a plastic hammer.

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 3. Status after the pump end cover is removed.

 

 

 

4. Remove the O-ring (3 0,3 1).

 

 

 

5. Remove the adjustment spring.

 

    6. Remove the spring seat from the pump housing (51).

 

       

7. Remove the plunger plug assembly.

 

 

         

8. Use the hook to remove the slide track plate.

 

 

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9. Remove the clamp spring with the clamp (7).

  

   10. Remove the front cover (8).

 

 

       11. Remove the O-ring.

 

 

      14. Remove the bearing pads (14).

 

 

    15. Remove the bearing.

 

 

       

16. Remove the inclined plate.

 

 

    17. Remove the flow distribution plate.

 

 18. Remove the card spring (28).

 

 

         

19. Remove the filter screen (26).

 

 

 

  

20 Remove the retaining bolt (67) for the flow adjustment valve block (M8 x

25L: 2s)

If the bolt is coated with Loctite before assembly, please do not remove the cover bolt if not necessary.

· Tool: 6mm (factory 1)

 

 

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21. Separate and adjust the valve body. Because the binding surface has an O-ring, please be careful.

 

 22. Remove the flow adjustment valve spool.

 

 

    23. Remove the 3 disc springs and spring seats.

 

  

24. Remove the inner hexagon bolts and separate the cover bolts

(M830L: 2s)

· Tool: 6mm (factory —)

 

   

  26. Remove the overflow valve. Remove the inner hexagon bolts.

Note: Disassemble this part only if required.

· Tool: 24 mm (2e)

 

 

  

27. Remove the adjustment bolts

 Note: Due to the valve core.

 

 

   28. Separation spring.

 

 

    

29. Remove the spool.

 30. Disassembly of the drive shaft

 Remove the clamp spring and the bearing

 

 

 

      31. It may be difficult to remove the bearings and can be struck with a plastic hammer.