Modern cars are equipped with hydraulic telescopic dampers. The shock-absorbing fluids used in them are operated in harsh conditions: depending on the season, the heating temperature of the AF varies from +140 to -60 degrees. Oil pressure in dampers can also increase up to 10 MPa.
Features of damping compositions
In cars, low-viscosity petroleum oils or a mixture of turbine and transformer oils in a 1:1 ratio are used as AF. However, such substances have a drawback - their viscosity increases with decreasing temperature, which can provoke a tightening of the mechanisms.
For dampers of domestic cars, oil MGP-10 is used, for other vehicles - all-weather shock absorber fluid AZh-12T or a mixture of transformer and turbine oils. Lubricants are characterized by low viscosity and low pour point. The composition of liquids includes various additives that ensure their performance in a wide temperature range.range.
Shock-absorbing fluid АЖ-12 is most in demand in lever-cam telescopic dampers. It consists of mineral low-viscosity oil and polyethylsiloxane fluid with a package of antioxidant and antiwear additives. It maintains performance at elevated pressure and temperature, has excellent mechanical and thermal stability. Liquid AZh-12T is poured into systems, parts of which are made of low-resistant rubber.
Shock-absorbing liquid MGP-10 of all-weather type is designed for hydraulic dampers of a car. It is a mixture of polyethylsiloxane fluid, transformer oil, animal fat, antifoam and antioxidant additives. On cars of the VAZ family, the use of MGP-10 provoked accelerated wear of the telescopic struts. Especially for these cars, another shock absorber fluid was developed - MGP-12, which provides increased protection for mechanisms.
This is a high quality shock absorber fluid that is a mixture of highly refined low viscosity oil and polyethylsiloxanes. Due to its high performance, it can be used in dampers operating at temperatures from -60 to +130 degrees.
This is a shock absorber fluid consisting of spindle and transformer distillates with the addition of antioxidant, depressant, antifoam and antiwear additives. Pouredtool in telescopic struts and vehicle dampers.
What is the risk of an untimely replacement of the fluid in the shock absorber?
The main task of dampers is to dampen vibrations that occur when the vehicle is moving. With timely replacement of the lubricant, the car runs softer and fits into the turn more stably. The grip of the rubber with the track is improved.
A failing shock absorber will cause failure of bearings, hubs and uneven tire wear, 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 available with or without a diaphragm and require a certain amount of dampening fluid. Membrane-equipped parts are equipped with a rubber diaphragm through which lubricant and air are separated. Reduced airspace may cause the damper to become unstable.
There is no air gap in shock absorbers without a membrane. The oxygen necessary for the movement of the rod is in the composition of the oil. Viscosity will decrease when the rod enters the part. The operation of the shock absorber is disturbed by a lack or excess of lubrication.
How to choose oil
Auto shops offer a wide range of brands of high quality shock absorber fluids. One of the most popular is ATF. However, some car owners prefer shock absorber fluid.Lukoil - AJ.
The main characteristic of the oil, which is based on when choosing, is the degree of viscosity: the thicker it is, the more difficult it is for the piston to move. Too liquid mixture also adversely affects the performance of the damper, leading to premature wear.
On containers with shock absorber fluid, 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 choosing a fluid, it is also worth considering that thick mixtures are more suitable for tracks without significant damage. When driving on roads with a lot of bumps and holes, the vehicle's maneuverability is lost.
The most popular low viscosity shock oils are:
- MGE-10A with anti-foam and antioxidant additives.
Special attention should be paid to the additives added to the damper fluid, as many of them can adversely affect rubber and silicone o-rings, which can lead to destruction and oil leakage.
How much grease to fill?
Shock absorbers that do not have anti-breakdown do not require accuracy when filling oil. But at the same time, too little fluid can lead to a deep IFP, which causes a knock in the damper. Overfilling with fluid can cause the expansion tank cap to pop out.
Shock absorbers with anti-breakdown need to fill the exact amount of liquid. Moreover, the more breakdowns, the higher the accuracy should be. If there is a shortage of oil, the anti-breakdown stops functioning, and its excess completely disables the part.
No more than 250 milliliters of shock absorber fluid is usually poured into such mechanisms. Some models have a limit of 100 ml. The specific amount depends on several criteria:
- Stem diameter. Measured with a compass.
- Stroke in millimeters. Determined by measuring the length of the part of the rod that comes out of the shock body.
- IFP diameter. Corresponds to the internal diameter of the expansion tank. To determine the size of the IFP, the inside of the tank is measured.
- Piston and rod areas.
- Distances the IFP travels while the damper is operating.
- IFP depth. The more - the less filled shock absorber.
After determining all of the above parameters, it is easy to calculate the amount of lubricant that needs to be poured into the suspension part.
Consistency of oils
Low viscosity lubricants offer the following benefits:
- Increasing the stability of the car on the track due to the rapid operation of the shock absorber.
- Quick response of the damper to the actions of the driver, which increases the maneuverability of the machine.
- Fast smoothing out road bumps and easy vehicle weight transfer.
- Low level shock absorber fluidsviscosities are recommended for crossovers and SUVs as they operate in rough road conditions.
Advantages of high viscosity oils:
- Provides a quiet and even ride on smooth roads, smoothly absorbing any potholes in the road.
- Car rolling stability.
- Deceleration of shock absorber wear.
- Ensuring full road contact when cornering at high speeds.
Shock absorber oils are selected based on viscosity grade, operating conditions and damper characteristics. Choosing the right fluid ensures a comfortable and safe driving experience.