Hydraulic cylinder 

         Faults

        Analysis

         Solution

Hydraulic cylinder can not be lifted.

PTO is not connected.
There is no air source.
Ball valve under the oil tank is not open.
Pressure is too low.
Pneumatic hose and oil hose are connected incorrectly.
Quick-change connectors (male and female) are connected incorrectly.

Check PTO.
Check if air source is smooth.
Open ball valve and check if hydraulic oil is enough.
Start the engine, let pressure up to more than 7.5 kg.
Check if pneumatic hose and air hose are connected correctly.
Fasten quick-change connectors(male and female).

The speed of cylinder for lifting and declining is too slow.

Pressure is too low.
Pneumatic hose is curved.
The viscosity of hydraulic oil is too high.

Start the engine, let pressure up to more than 7.5 kg.
Reset the pneumatic hoses.
Change proper hydraulic oil.

Cylinder can not be lifted completely.

Seriously overload.
Oil level of oil tank is low.
Pressure is too low.
The installation position of limit valve is wrong.

Unload manually.
Refill the original type hydraulic oil.
Let pressure up to more than 7.5 kg.
Adjust the position of the limit valve.

The cylinder tubes comes apart from cylinder body.

The installation position of limit valve is wrong.
Suspension is too long.
Cargo is large bulk, while the lifting angle of cabin is too small.

Adjust the position of the limit valve.
Design and install the vehicle again.
Adjust the angle of lifting, make the stroke to the highest angle.

The cylinder is strained.

Unbalanced loading.
The space between brackets is beyond tolerance.
The installation of cylinder is not vertical.
When the cylinder raise, cylinder tubes and other accessories collide and destroy.
The land is uneven when discharging.
Hydraulic oil is too dirty.
Operate improperly.

Load the cargo correctly.
Adjust the space between brackets.
Design and install the vehicle again.
Operate and follow the standard instructions.
Change hydraulic oil, air filter and oil filter.
Operate in accordance with standard requirements.

Cylinder tubes cannot be lifted in sequence.

The cylinder tubes are deformed because of rollover, outer power collision or  discharge by severe brake.

Replace the damaged parts.

The cylinder  leaks (infiltrates) the oil.

Unbalanced load repeatedly.
Cylinder tubes are strained.
The installation position of cylinder is not as required.

Load and unload correctly, and change seals kits.
Replace cylinder tubes and seal kits.
Change cylinder tubes and adjust the position of cylinder.

Pneumatic control valve fails.

Pneumatic hose leaks.
Pneumatic hose is curved.

Replace hose and fasten the connectors.
Rearrange the layout of pneumatic hose.

Hydraulic cylinder cannot drop down.

The pneumatic hose between lifting valve and pneumatic valve is blocked.
Cabin or stabilizing frame deforms.
There is no mail air source for lifting system.

Check and replace pneumatic hose.
Reform cabin or stabilizing frame.
Check the main air lines.

Cylinder shakes.

Oil tank lack of hydraulic oil.
PTO is damaged.
The oil flow of inlet pipe changes too large.
Cabin or auxiliary girder deforms.

Refill the original type hydraulic oil.
Replace PTO.
Check oil lines.
Revise or Maintain deformed cabin or auxiliary girder .

Air port of cylinder spills oil.

Air filter of oil tank is dirty.
Oil level is out of liquidometer standard.
Operate improperly, drive as dropping down the cylinder.
The type of hydraulic oil is wrong.

Replace air filter.
Release some oil in oil tank.
Strictly operate as required.
Change hydraulic oil as required.