Timely service hydraulic system is critical to the longevity of the family of tractors MTZ. Oil contamination with wear products, metal shavings or moisture leads to accelerated failure of expensive components, such as pump NSh and distributor. Ignoring signs of contamination can result in a major overhaul of the entire system, which is not economically feasible compared to routine maintenance.
Equipment owners are often faced with a situation where changing filters and oil does not bring the desired result, and the operation of attachments becomes sluggish or intermittent. This is a sure signal that deposits have accumulated in the lines and cavities of hydraulic cylinders, which require mechanical or chemical removal. A critical level of contamination is considered to be the presence of more than 0.05% of solid impurities in the volume of working fluid. The flushing process allows you to restore the efficiency of the system and prevent jamming of the spools.
Before starting work, you need to clearly understand the structure of your tractor, be it a classic MTZ-80/82 or more modern modifications. The design of the hydraulic system of these machines suggests the presence of several zones where sludge and dirt most often settle. Proper preparation and the availability of special tools are 90% of the success of the operation. Next, we will analyze in detail all stages of the process.
Diagnostics of hydraulic condition before servicing
The first step should always be a thorough diagnosis to assess the extent of the problem and choose a cleaning method. A visual inspection of the oil taken from the tank can tell a lot about the condition of the system. If the liquid has a milky tint, this indicates water ingress, which leads to corrosion of internal surfaces and destruction o-rings.
Particular attention should be paid to work hydraulic pump. The appearance of extraneous noise, hum or whistle when idling often indicates cavitation or the presence of air in the system, which may be a consequence of a clogged suction line. It is also worth checking the oil temperature after an hour of operation: excessive heating indicates internal leaks or increased friction due to dirty lubricant.
- 🔍 Check the color of the oil: blackening indicates oxidation or the presence of combustion products.
- 🌡️ Measure the heating temperature of the hydraulic tank in operating mode.
- 🔊 Listen to the operation of the NSh-32 or NSh-50 pump for knocking noises.
- 💧 Inspect the tank breather for contamination that is preventing the system from breathing.
⚠️ Attention: If obvious metal shavings (“silver chips”) are visible in the drained oil, this is a sign of destruction of the pump gears or plain bearings. Simple washing is not enough here - troubleshooting and replacement of damaged components is required.
An additional indicator is the behavior of the attachment. If the plow or bucket lowers spontaneously or rises jerkily, it means that there is contamination in the distributor or hydraulic cylinders that prevents the valves from sealing tightly. System pressure It can also jump, which is recorded by a pressure gauge when checking.
Required tools and flushing fluids
For high-quality flushing of the tractor hydraulic system MTZ You will need not only a standard set of keys, but also special tools. The main element is a container for draining waste liquid with a volume of at least 20 liters, since the total volume of the system can vary depending on the model and the presence of a hydraulic disconnector. It is important to prepare clean, lint-free rags and special plugs for the holes.
The choice of flushing fluid is key. It is strictly not recommended to use gasoline, kerosene or diesel fuel, as they have an aggressive effect on rubber seals and cuffs, causing them to swell or crack. Best to use spindle oil (for example, AU or analogues) or specialized flushing oils for hydraulics, which have good solvent power but are safe for rubber.
You will also need:
- 🛠️ Set of socket and open-end wrenches (from 10 to 36 mm).
- 🧹 Brushes with hard bristles for cleaning the internal surfaces of the tank.
- 🧴 A syringe or pear for pumping out remaining liquid from hard-to-reach places.
- 🧼 Solvent (only for metal parts, without rubber).
When working with chemical liquids, be sure to use personal protective equipment: gloves and goggles. Vapors from solvents or hot oil may be harmful to health. Carry out all work in a well-ventilated area or outdoors, away from sources of fire.
Use a magnet on a flexible rod, lowered into the neck of the tank, to collect metal shavings from the bottom, where it is impossible to reach with your hand.
Preparing the tractor and draining used oil
The preparation process begins by placing the tractor on a level surface. This is necessary to ensure complete drainage of the liquid by gravity. The engine must be turned off and the hydraulic distributor lever must be moved several times to all positions with the engine running (in the initial stage) to disperse the oil through the system, and then stopped. However, if the system is heavily contaminated, it is better to drain the main oil immediately after stopping, before the suspension settles.
Hydraulic tank drain plug on tractors MTZ usually located in the lower part of the transmission housing or under the operator's seat, depending on the version. Before unscrewing, thoroughly clean the surface around the plug from dirt so that it does not get inside when opening. Use a wide container as the flow may be strong and splash.
To speed up the process and more completely empty the system, you can briefly start the engine (for a few seconds), creating pressure that will push the remaining liquid out of the lines. However, this must be done extremely carefully so as not to air the pump. After the main drain it is necessary to remove filter element and the oil receiver mesh, which often become clogged with paraffin and dirt.
Procedure for draining:1. Clean the dirt-protecting surfaces around the plugs.
2. Unscrew the tank drain plug.
3. Remove the hydraulic tank hatch cover (under the seat).
4. Remove the oil intake screen.
5. Let the oil drain for 15-20 minutes.
If the system has power steering (power steering), do not forget to drain the fluid from its reservoir, since in older MTZ models it may be powered from a common system or have its own circuit that requires maintenance. It is convenient to pump out the remaining oil from the power steering reservoir with a syringe.
Mechanical cleaning of the hydraulic tank and filters
After draining the liquid, access to the internal cavity of the hydraulic tank opens, which on tractors MTZ also serves as a reservoir for transmission oil. This makes access easier, but requires extra care to avoid clogging the transmission. All accumulated sludge, dirt and paraffin deposits must be manually removed through the hatch under the seat.
Use a rag and a scraper (preferably wooden or plastic so as not to scratch the metal) to clean the walls and bottom of the tank. Pay special attention to the corners and places of welds where deposits most often form. If there are magnetic plugs or magnets at the bottom of the tank, they need to be wiped dry, removing all metal dust.
| System element | Type of pollution | Cleaning method | Check frequency |
|---|---|---|---|
| Hydraulic tank | Sludge, paraffin, water | Mechanical, rags | Every 2 seasons |
| Oil receiver mesh | Large chips, dirt | Flushing with diesel fuel | Every 500 operating hours |
| Fine filter | Fine suspension | Replacement (not washed) | Every oil change |
| breather | Dust, dirt | Blowing, washing | Monthly |
The fine filter element (paper or cardboard) cannot be washed - only replaced with a new one. The coarse mesh (metal) can be thoroughly washed in clean kerosene or diesel fuel and blown with compressed air. Make sure that the mesh cells are completely free of dirt before replacing it.
☑️ Cleaning the tank
Flushing the system using the circulation method
After mechanical cleaning of the tank, it is necessary to rinse the internal lines, hydraulic cylinders and distributor, where hands cannot be reached. For this purpose, the circulation washing method is used. Flushing liquid (spindle oil or special composition) is poured into the tank in the volume necessary for the pump to operate without airing (usually 5-7 liters).
Start the tractor engine and let it run at minimum speed for 2-3 minutes. Then briefly (5-10 seconds) raise and lower the attachment several times so that the flushing fluid passes through all circuits, including hydraulic cylinders and distributor spools. Do not hold the distributor in the extreme position for a long time so as not to overheat the liquid.
Important: if the system has hydraulic disconnector (pump isolation valve), it must be switched several times during flushing so that the liquid gets into all branches. After the run cycle, the engine is turned off and the flushing fluid is immediately drained. It will be dirty, as it will collect the remaining sludge from the walls of the lines.
⚠️ Attention: Never use flushing fluid for work under load (for example, digging). It has worse lubricating properties than operating oil and can lead to scuffing of the pump friction pairs.
The circulation flushing procedure can be repeated 1-2 times if the drained liquid remains too dirty. For complex cases when there was a lot of water in the system, special moisture displacing compounds can be used, but they require strict adherence to the chemical manufacturer’s instructions.
What should I do if the system is noisy after flushing?
The humming noise may be caused by residual air in the system. Try raising and lowering the hitch several times at minimum engine speed. If the hum does not go away, check the tightness of the pump suction line for air leaks.
Assembly, filling and removal of air plugs
The final stage is assembly and filling with fresh oil. Reinstall the cleaned oil receiver mesh, a new fine filter and tighten the drain plug. Make sure all O-rings on plugs and caps are in good condition; Replace them if necessary to eliminate air leaks and leaks.
Fill in fresh hydraulic oil (usually MG-30, MG-46 or all-season MG-10-V) through a funnel with a fine mesh to the required level. On tractors MTZ The level is checked using a dipstick or through a control hole (depending on the year of manufacture). Do not pour oil above the maximum mark, as when heated it will expand and be squeezed out through the breather.
After refueling, it is necessary to remove air pockets:
- 🚜 Start the engine and let it idle for 2-3 minutes.
- 🔄 Smoothly raise and lower the attachment 5-7 times until it stops.
- 👀 Check the oil level and add if necessary (the level will drop as the oil fills the cylinders).
- 🔍 Inspect connections for pressure leaks.
Air in the system is dangerous because it causes compression of the working fluid, which leads to jerking of mechanisms and heating. If after several lifting and lowering cycles the operation becomes smooth and the pump noise disappears, the procedure is completed successfully. Check your work power steering, turning the steering wheel from lock to lock.
High-quality flushing and oil change extend the life of the MTZ hydraulic pump by 1.5-2 times, preventing expensive repairs.
Frequently asked questions (FAQ)
How often do you need to completely flush the hydraulic system at MTZ?
It is recommended to carry out a complete flushing and disassembly of the tank every 2-3 seasons or every 1000-1500 operating hours. However, filter changes and oil checks should be carried out every 500 operating hours or before starting field work.
Is it possible to mix different brands of hydraulic oils when topping up?
Mixing oils from different manufacturers and bases (mineral and synthetic) is highly discouraged. This can lead to sedimentation, foaming and loss of lubricity. It is better to completely replace the fluid if the brand is unknown.
Why do hydraulics work worse after changing the oil?
This may be due to the fact that the new oil has a different viscosity, or there are air pockets in the system. It is also possible that the old, thicker oil from contaminants hid the wear of the seals, and the new, more fluid oil revealed leaks through the gaps.
What oil is better to fill in MTZ-82 in winter?
All-season hydraulic oils with a low pour index, for example, MG-10-V or imported analogues with a viscosity of ISO VG 32-46, approved for operation at low temperatures, are optimally suited for winter operation.