Precaution for oil seal

The function of the seal is to close the gap of oil overflow in the box chamber and prevent dirt such as dust and sand from invading the box chamber. However, if it is installed or misused, it is easy to cause oil leakage and affect the regular operation of the machine, which will burn the bearing, break the gear, unscrew the transmission shaft or other serious faults.

(1) Before installing the oil seal, check whether the surface of the journal is too rough and free of scars, especially long scars along the axial direction. If the surface of the journal is too rough, it is easy to damage the oil seal or accelerate the wear of the lip 1:3 and destroy its sealing performance. Suppose the journal surface causes serious blunt impact scars due to improper disassembly and assembly. In that case, the oil seal lip will not fit tightly with the journal surface, resulting in oil leakage. After surfacing the damaged part in the above two cases, turn the lathe round again according to the specified journal size, or replace the shaft with a new one. If the journal has only metal burrs or shaft head flash, it can be polished with a file to prevent damaging the oil seal lip when installing the oil seal.

(2) Check the oil seal lip for damage, crack or oil corrosion. If there are these terrible phenomena, replace the oil seal with a new one.

(3) When installing the framework oil seal, to prevent the oil seal lip 121 from being stretched, deformed or scratched, a unique installation tool must be used. If there is no such tool, the following method can be used for installation: first roll a layer of transparent hard plastic film (commonly known as cellophane) on the journal and even the shaft head, apply a little oil on its surface, put the oil seal into the shaft head wrapped with plastic film, push the oil seal slowly to the journal with uniform force, and then pull out the plastic film. Note: do not install the lip in the wrong direction. Make it face the inner side of the oil stored, and the side with trademark and specification faces the outer side. Because lip 1:3 can only be sealed in one direction, if the oil seal is reversed, it is bound to cause oil leakage, weakening or failure of sealing effect. Avoid skewing the oil seal or beating the oil seal surface with tools such as a hammer and rod. Otherwise, it is easy to cause damage to the oil seal.

(4) During installation, keep the oil seal (especially the lip) and journal clean, and pay attention not to make the oil seal jump out of the spring groove from the tightening spring. If the self-tightening spring is loose and the elastic force is weakened, cut it down according to the situation and connect the ends firmly to continue to use.

The water stop ring of the cylinder liner is an “O” shaped rubber part, and the cross-section is circular mainly. Compared with the skeleton oil seal, it has a simple structure, neither skeleton nor self-tightening spring. It is sealed by relying on the flexibility and elasticity of the rubber itself. Improper installation will cause a large amount of cooling water in the water jacket to seep into the crankcase, resulting in engine oil deterioration, poor lubrication quality, aggravation of wear of moving parts of the engine, and even significant faults such as burning tile and holding shaft. Therefore, the following matters shall be paid attention to when installing the water stop ring:

(1) If the water stop ring is too thin or the water seal groove of the cylinder liner is too deep so that the water stop ring cannot be higher than a certain height of the arc surface after being installed in the water seal groove of the cylinder liner, at this time, wrap a layer of asbestos rope at the bottom of the water seal groove, apply water-resistant calcium base grease, then put the water stop ring into the water seal groove, and then press the cylinder sleeve into the seat hole of the machine body.

(2) If the water stop ring is too thick or the water seal groove of the cylinder liner is too shallow, and the water stop ring is too much higher than the arc surface after being installed, it will not only be challenging to install the cylinder liner, but also crush the rubber water seal or even the cylinder liner. The rubber water seal can be polished evenly with emery cloth until installed in the water seal groove with an appropriate protruding height. Then apply grease on the surface of the rubber ring to press the cylinder liner into the seat hole of the engine body.

(3) If the thickness of the water stop ring is uneven or the depth of the water seal groove is different, and the protruding height of the rubber ring after installing the cylinder liner is uneven, carefully check whether it is a problem with the rubber ring or the water seal groove, and replace the problematic parts.

(4) Before the rubber water stop ring is sleeved into the cylinder liner water seal groove, the rubber ring and water seal groove shall be cleaned, and impurities and dirt shall be avoided during installation. After the rubber ring is installed on the cylinder liner, carefully check whether it is twisted and grooved. Before installing the cylinder liner, carefully remove the dirt on the cylinder block’s upper and lower bearing holes, apply a layer of oil on the surface of the lower bearing hole, and then slowly press the cylinder liner into the bearing hole.