Wholesale Hitachi excavator parts manufacturer and supplier

1. The starter and flywheel teeth are not meshed well. The ring gear and the starter gear collide when starting the engine, causing tooth damage or single-sided wear of the teeth. If more than three teeth are damaged or worn seriously, it will be difficult for the starter gear and the ring gear to mesh.

2. Cylinder sticking. When the engine temperature is too high, the engine is stopped and the heat is difficult to dissipate. The piston ring at high temperature sticks to the cylinder and cannot start after cooling.

3. Crankshaft lock. Due to lubrication system failure or lack of oil, the sliding bearing rubs dry, which eventually locks the crankshaft and cannot start.

4. The injection pump plunger is stuck.

Possible air in the hydraulic oil or internal component wear.

Solution: Bleed air from the system, replace worn components.

The steps for replacing a control valve are to shut down the machine, release system pressure, remove the old control valve, install the new control valve, start the machine and check operation.

The batteries we use are all lead-acid batteries for starting. Because this type of battery has the characteristics of large starting current and can meet the power supply requirements of the starter motor.

Reasons from the piston group
1. The piston ring gap is too small. If the opening gap, side gap or back gap of the piston ring is too small, the piston ring will be stuck due to heat expansion when the engine is working, and it will be pressed tightly against the cylinder wall, or the piston ring will be broken, which can easily pull out grooves on the cylinder wall.
2. The piston pin is out. Because the piston pin retaining ring is not installed or falls off or breaks, the piston pin will be out during movement, which can easily damage the inner wall of the cylinder and cause the cylinder to blow into the crankcase.
3. The piston cylinder gap is too small or too large. If the piston material is poor, the manufacturing size error is too large, or the piston is deformed after the piston pin is assembled, the matching gap between the piston and the cylinder is too small, and the piston is stuck after heat expansion, which will then damage the cylinder wall.
4. The piston ring is seriously carbonized. Excessive carbon deposits cause the piston ring to stick or bite in the ring groove. At the same time, carbon deposits are a hard abrasive that will grind into longitudinal grooves on the cylinder wall.
5. The piston is seriously off-cylinder. Due to the bending and twisting of the connecting rod, the parallelism and coaxiality deviations of the connecting rod journal, main journal, and piston pin seat are too large, causing the piston to be significantly off-cylinder, which will accelerate the wear of the piston ring, piston and cylinder wall and destroy the formation of the oil film.

Reasons for cylinder sleeves
1. The roundness and cylindricality tolerances of the cylinder sleeves exceed the allowable range, which greatly reduces the sealing of the piston and cylinder sleeves. The high-temperature gas in the cylinder flows down, destroying the oil film between the piston and the cylinder wall, and then causing cylinder pulling.
2. The cylinder sleeve is deformed during the assembly process. For example: the protrusion of the upper end surface of the cylinder sleeve is too large, and the cylinder sleeve is deformed after the cylinder head is installed; the cylinder sleeve water blocking ring is too thick, and the cylinder sleeve is deformed after being pressed into the body, which can easily cause cylinder pulling.

Reasons for use:
1. Whether the size of the cylinder sleeve used during assembly does not match the cylinder body and piston.
2. The air filter is not sealed, which makes the filtering effect worse. Dust, sand and other impurities in the air are sucked into the cylinder, forming abrasive wear. Tests show that if a few grams of dust are sucked in every day, the wear of the cylinder liner will increase by more than 10 times.