Modern cars are equipped with telescopic hydraulic dampers. The shock absorbing liquids used in them are operated under harsh conditions: depending on the time of year, the heating temperature of the coolant varies from +140 to -60 degrees. The oil pressure in the dampers can also increase to 10 MPa.
Features of depreciation compounds
In automobiles, oil of low viscosity or a mixture of turbine and transformer in a ratio of 1: 1 are used as AF. However, such substances have a drawback - their viscosity increases with decreasing temperature, which can provoke a toughening of the mechanisms.
MGP-10 oil is used for dampers of domestic automobiles, for all other vehicles - AZh-12T all-weather shock-absorbing liquid or a mixture of transformer and turbine oils. Lubricants are characterized by low viscosity and low pour point. The composition of the liquids includes various additives, ensuring their performance in a wide temperature range.
Popular AZ-12
AZh-12 shock absorber fluid is most in demand in lever-cam telescopic dampers. It consists of low-viscosity mineral oil and polyethylsiloxane liquid with a package of antioxidant and antiwear additives. It remains operational at elevated pressures and temperatures, and has excellent mechanical and thermal stability. -12 fluid is poured into systems whose parts are made of low-resistance rubber.
MGP-10 oil
MGP-10 shock-absorbing fluid of an all-weather type is designed for hydraulic dampers of a car. It is a mixture of polyethylsiloxane liquid, transformer oil, animal fat, antifoam and antioxidant additives. On vehicles of the VAZ family, the use of MGP-10 provoked accelerated wear of telescopic racks. Especially for these cars, another shock-absorbing liquid, MGP-12, was developed, which provides increased protection of mechanisms.
AZh-170
This is a high-quality shock-absorbing liquid, which is a mixture of highly viscous low-viscosity oil and polyethylsiloxanes. Due to its high performance, it can be used in dampers operating at temperatures from -60 to +130 degrees.
GRG-12
It is a shock absorber fluid consisting of spindle and transformer distillates with the addition of antioxidant, depressant, antifoam and antiwear additives. The product is poured into telescopic racks and dampers of vehicles.
What is fraught with untimely fluid replacement in the shock absorber?
The main task of dampers is to damp vibrations that occur when the vehicle is moving. With timely replacement of the lubricant, the car is softer and more steadily fits into the turn. The grip of rubber with the track is improved.
Failure of the shock absorber entails the failure of bearings, hubs and leads to uneven wear of the tires, which can cause an accident. The correct operation of the part depends on two main parameters: the volume and consistency of the oil.
Dampers are produced with or without a membrane and require a certain amount of shock absorber fluid. Membrane-equipped parts are equipped with a rubber diaphragm, through which grease and air are separated. Reduced airspace can lead to unstable damper operation.
In shock absorbers without a membrane there is no air gap. Oxygen, necessary for the movement of the stem, is part of the oil. Viscosity will decrease when the stem enters the part. The shock absorber is broken when there is a lack or excess of lubricant.
How to choose oil
In car dealers, a wide range of high-quality shock absorber brands is offered. One of the most popular is ATF. However, some car owners prefer Lukoil - AZ shock absorber fluid.
The main characteristic of the oil, on which they rely when choosing, is the degree of viscosity: the thicker it is, the more difficult it is to move the piston. A too liquid mixture also negatively affects the performance of the damper, leading to its premature wear.
On tanks with shock absorber, manufacturers usually indicate the degree of viscosity. When choosing a car owner, it is advisable to focus on these indicators and climatic conditions in a particular region.
When selecting a fluid, it is also worth considering that for tracks without significant damage thick mixes are more suitable. When driving on roads with a large number of bumps and holes, the car’s maneuverability is lost.
The most popular shock absorbing oils with low viscosity are:
- MGE-10A;
- MGP-10;
- AZh-12T;
- MGE-10A with antifoam and antioxidant additives.
Particular attention should be paid to additives added to the damper fluid, since many of them can adversely affect rubber and silicone o-rings, which can lead to their destruction and oil leakage.
How much grease should be added?
Shock absorbers that do not have anti-breakdown do not require accuracy when filling oil. But at the same time, too low a quantity of liquid can lead to a deep occurrence of IFP, which causes a knock in the damper. Excessive filling with liquid may knock out the cap on the expansion tank.
Anti-breakdown shock absorbers need to be filled with the exact amount of fluid. Moreover, the more breakdowns, the higher should be accuracy. With a shortage of oil, the breakdown ceases to function, and its excess completely destroys the part.
In such mechanisms, usually no more than 250 milliliters of shock-absorbing liquid is poured. Some models have a limit of 100 ml. The specific amount depends on several criteria:
- Stem diameter Measured with a compass.
- Stroke in millimeters. It is determined by measuring the length of the part of the rod emerging from the shock absorber body.
- Diameter IFP. Corresponds to the inner diameter of the expansion tank. To determine the size of the IFP, the inside of the tank is measured.
- The area of the piston and rod.
- The distances the IFP travels while the shock absorber is operating.
- Depth IFP. The more - the less the shock absorber is filled.
After determining all of these parameters, the amount of lubricant that can be filled into the suspension part is easily calculated.
Oil consistency
Low viscosity lubricants have the following advantages:
- Increasing the stability of the car on the track due to the fast operation of the shock absorber.
- The quick response of the damper to the actions of the driver, which increases the maneuverability of the machine.
- Fast smoothing of road irregularities and easy movement of vehicle weight.
- Shock absorbing liquids with a low level of viscosity are recommended for crossovers and SUVs, since they are operated in rough roads.
Benefits of high viscosity oils:
- Provide a calm and uniform ride on flat roads, smoothly damping all potholes of the road.
- Car rolling stability.
- Slow shock absorber wear.
- Ensuring full contact with the roadway when cornering at high speed.
Oils for shock absorbers are selected based on the degree of viscosity, operating conditions and the characteristics of the damper. The right fluid choice guarantees comfortable and safe driving.