Rear axle MTZ-80, 82: Diagram, adjustment, repair

Design and principle of operation of the bridge

The bridge has a kinematic diagram with final drives located inside. All parts of the gearbox operate in a common oil bath, are spray lubricated, and are combined with the gearbox and intermediate part of the transmission in a single lubrication system. Oil is poured through the plug in the upper gearbox cover to the level of the lower edge of the inspection hole. The total volume of transmission oil is 40 liters.

MTZ rear axle diagram

main gear

The gearbox mechanism receives longitudinal rotation from the gearbox output shaft attached to the front wall of the rear axle housing. The transmission is carried out through a bevel gear with helical teeth. In a bridge design, this pair of gears is called the main gear. The gears receive the gear ratio created by the gearbox and convert longitudinal rotation into transverse rotation. The drive gear sits in the grooves of the housing output shaft shank and is tightened with a cotter pin. The final drive gear is attached to the differential housing with bolts and nuts with bent locking plates.

Differential

The mechanism performs the function of distributing torque to the drive wheels when turning the tractor, providing different angular speeds of rotation of the drive wheels.

Cross member, satellites and gear axle shafts Differential MTZ 80

Differential satellite

The device is a planetary gear enclosed in a cylindrical housing consisting of two parts connected by bolts. Inside the group there is a cross covered by two halves of a body with four satellites in the form of cylindrical bevel gears rotating on bronze bushings. Steel thrust washers are installed between the satellite body on the axis. The satellites interact with the left and right side bevel gears, which transmit rotation on their respective sides to the drive gears of the axle's final drive. Bronze thrust washers are installed between the drive shaft gears and the housing. The gears in the housing housings rotate on tapered roller bearings.

Final drives

Part of the mechanism that transmits rotation from the differential directly to the drive shafts. The corresponding shafts of the left and right main gears are inserted into the splines of the differential side gears with their inner ends. Each part is supported by two roller bearings. The drive spur gears of the final drives are located on shafts, which are made integral with the part. Each shaft is supported by two roller bearings. The driven gears of the final drives are placed directly on the drive shafts and are connected by splined bushings. The half-shafts are supported by two ball bearings: the inner one is located in a hole in the crankcase bulkhead, the outer one is located in the cast-iron housing of the axle shaft. To avoid axial movements, the part is fixed with a locking ring and a drive shaft housing cover with a self-tightening oil seal. In addition, the outer ends of the main drive drive shafts are connected on the right side to the right operating drums and parking brake drums, and on the left side to the left operating drums and differential lock drums. The parking and parking brakes are actuated through the tubular cavities of the main gear shafts by additional shafts. A separate mechanism at the bottom of the crankcase from the intermediate shaft of the box runs longitudinally to the drive shaft of the rear PTO with a cam clutch for switching modes. The shaft is supported by bearings installed in the holes of the crankcase transverse partitions.

Homemade MTZ blocking

A number of owners equip MTZ tractors with homemade mechanical locking devices.

The manufacture and assembly of the mechanics of the unit consists of several stages:

1. Grind the surface of the final drive shaft.
2. Make a sleeve in the shape of a spool of thread with slots inside. The bushing should move freely along the shaft splines.
3. Place the base for the lever to control the hub on the final drive cover. Inside the cover there is a fork that contacts the inner end surfaces of the sleeve. The fork has 2 bearings that directly move the bushing.
4. Bring the control handle into the cabin and equip it with position locks. When the handle moves, the sleeve moves and the locking clutch engages. The locking is activated at the operator's request and does not depend on the angle of rotation of the front wheels.

Rear axle of Belarus MTZ-82.1 tractor

Rear axle Belarus MTZ-82-1, 80-1, 82-2 1 - sprocket driving the main gear, on the right; 2 — satellite washing machine; 3 — differential cross member; 4 - satellite; 5 — differential housing; 6 — driven gear of the main gear; 7 — driven gear fastening nut; 8 — locking plate; 9 — differential housing cover; 10 — tapered roller bearing; 11 — tension bolt; 12 — main gear drive sprocket on the left; 13 — driven gear of the main gear; 14 — bearing; 15 — hatch cover; 16 — rear axle housing; 17 — driveshaft bushing; 18 — disk connecting to the lining group; 19 — intermediate disk; 20 - spring; 21 — squeezing disk; 22 — pressure disk; 23 — axle shaft; 24 - cuff; 25 — sleeve cover; 26 — bearing; 27 — differential lock mechanism cover; 28 — diaphragm cover; 29 — diaphragm; 30 — adapter; 31 — blocking shaft assembly; 32 — cuff; 33 — casing; 34 — clutch housing blocking; 35 — glass cover; 36 — bearing; 37 — cup of bearings; 38 — thickness; 39 — support washer; 40 — semi-axial transmission; 41 — main gear of the final drive; 42 — secondary shaft of the gearbox; 43 — rear axle cover. Main gear The main gear of the Belarus MTZ-82.1, 80.1 rear axle is a pair of bevel gears with spiral teeth. The main drive gear 41 is mounted on the splined end of the transmission output shaft 42, and the main drive gear 6 is attached to the differential housing flange 5 by twelve half-clearance bolts. Tapered roller bearings 10 must be adjusted for tension.

The force applied to the outer end of the teeth of the driven gear 6 of the main drive to rotate the differential in the bearings should be from 30 to 50 N when measured after turning the differential 4-5 full revolutions.

When tightening the bearings, it is necessary to periodically rotate the differential. Adjust the final drive of the Belarus MTZ-82-1, 80-1 rear axle in the following order: - install two sets of adjusting washers under the flange of the right window, then tighten the bolts with a torque of 80 to 100 Nm; — selecting gaskets 38 under the left flange of the bearing cup 37, install the required interference fit in the bearings. The lateral play of the main gear when the gears are engaged should be from 0.2 to 0.55 mm, but not more than 0.25 mm per pair. Lateral mesh play is monitored by an indicator that acts on the driven gear tooth in at least three of its positions. Tooth adhesion (contact) must be at least 50% of the tooth surface. The position of the cast should be at the center or near the top of the cone. If the print is unsatisfactory, you need to check the gear installation and adjust its position. Gear adjustments should only be made after adjusting the tapered roller bearings. Differential The differential of the rear axle of the Belarus MTZ-82.1, 80.1 tractor consists of a housing 5 and a cover 9, a cross member 3, four washers of 2 planetary shafts, two axle shafts 40 and two support washers 39 of the axle shafts and gear shafts. The differential housing and cover are connected by eight 11 waterproof bolts, which are secured in pairs against rotation with a safety cable. The holes for installing the crosspiece are machined after assembling the housing with the differential cover. Therefore, markings on the housing and on the differential cover are carried out by applying the same serial number. When installing the differential, it is necessary to combine these numbers on the mating parts. The teeth of the satellites 4 are in constant engagement with both drive shafts 40. The drive shafts are connected by grooves to the drive gears of the main gears 1 and 12. Solid washers 39 made of tin bronze are installed under the ends of the drive shafts. These lock washers are secured by tabs in the differential housing and cover. Final drives To increase torque and transmit rotation from the differential to the drive wheels of the Belarus MTZ-82-1, 80-1 tractor, final drives are used, which are two pairs of spur gears with straight teeth and are located on the right side and left rear axle. The drive gears of the main gears 1 and 12 are made integral with the splined shafts and are mounted on two bearings 36 in the holes of the cup 37.

One splined end of gears 1 and 12 is connected to the side gears of the differential, the other is used to install the connecting discs 18 of the brake. Thicknesses 38 with a thickness of 0.2 and 0.5 mm are installed under the flanges of the glass 37. These spacers regulate the clearance in the tapered roller bearings 10 of the differential and the transverse clearance between the teeth of the main gears. The driven gears of the final drives 13 are mounted on the splines of the axle shafts 23, each of which rotates on two ball bearings 14 and 26. The axle shaft covers 25 are secured in the axial direction through bearings 26.

MTZ-82 service and regulations

• Controls and Instruments
• Working with agricultural machinery
• Maintenance of the D-243 diesel engine
• Clutch adjustment
• Helmet
• Brakes for tractors Belarus
• PTO
• Front axle
• Front drive axle repair
• Hydraulic system and rear linkage
• Electrical equipment
• Service

Operation and maintenance of MTZ-82.1, 80.1, 80.2, 82.2

• Controls and Instruments
• Gearbox and power take-off control
• Rear linkage control
• Cabin elements
• Electrical components
• Grab
• Transmission of infection
• Gearbox and reduction
• Reverse gear
• Rear axle of tractor Belarus
• Rear axle differential lock
• Rear cardan shaft
• Brakes for tractors Belarus
• Pneumatic system
• FDA with bevel gearboxes
• FDA with helical planetary gearboxes
• FDA drive
• Working system
• Hydrostatic steering
• Power steering
• Hydraulic connection system
• Rear linkage adjustments
• Taxi Belarus
• Service
• Engine Maintenance
• Transmission Service
• FDA Service
• Hydraulic and steering service
• Front Axle Maintenance
• Maintenance of pneumatic and brake systems

Repair of MTZ-80

• Cylinder head repair
• Repair of piston unit D-240
• Repair of fuel equipment
• Starter repair
• Steering repair
• Front axle repair
• Repair of clutch and gearbox
• Gearbox repair
• Rear axle repair
• PTO repair
• Rear linkage hydraulic system repair
• Electrical equipment repair

MTZ-1221 maintenance and operation

• Control and tools
• Transmission of infection
• Grab
• D-260 engine maintenance
• Rear axle
• Service brakes
• Pneumatic equipment
• Power take-off
• Front axle
• Mounted hydraulic system
• Electronic rear linkage control
• Rear mount
• Helmet

MTZ-320 maintenance and operation

• Controls and Instruments
• Diesel
• Clutch and gearbox
• Rear axle
• Brakes
• Rear cardan shaft
• Front axle
• Helmet
• Fastening and coupling device
• Hydraulic system
• Electrical equipment
• Aggregation

Operation and maintenance of tractors

• Crankcase and crankcase lock
• Gas distribution mechanism
• Diesel engine fuel system
• Tractor engine control system
• Tractor engine cooling system
• Diesel starting system
• Tractor power transmissions
• Tractor transmission T-150, T-150K
• Drive axles of wheeled and tracked tractors
• Tractor frame and controls
• Chassis and steering of wheeled tractors

Not available:

Possible malfunctions of the rear axle of the MTZ-80/82 tractor. Detection and elimination methods

When using MTZ-80/82 tractors, it is possible that the engagement of the main gears may be interrupted, and the gear teeth, splines and main gear bearings may wear out. A sign of these malfunctions, as a rule, is increased noise in the rear axle housing.

Operation of MTZ-80/82 tractors shows that the design of the rear axle is quite reliable, and the above malfunctions are quite rare, as a rule, they arise due to improper operation: significant overloads of the tractor, low oil level in the rear part of the axle housing, as well as incorrect assembly after repair.

To determine the specific cause of the malfunction, it is first necessary to measure and diagnose the total side clearance between the gear teeth of the entire transmission.

Useful tips

The hydraulic locking system is used for field work and driving on snowy roads. It is recommended to use a blocker when plowing soil on slopes, since the system ensures that a straight path of movement is maintained.

When driving on paved roads, differential locking causes increased tire wear, so the device should be disabled.

Using a locked differential on a slippery road is allowed at a speed of no more than 10 km/h (due to the danger of the car skidding).

Detailed description of repair actions

Inside the single housing is the differential and center gear. Therefore they need to be considered together. A technical inspection requires careful consideration of the following information:

1. Oil level.
2. Current condition of the drive shaft.
3. Distances between axles.

At this stage, further adjustments to the fastening of the structure are carried out. Parts that have become unusable are removed and replaced with new ones.

Wheel gears should also be checked for oil level. These parts constantly rub against each other and what is nearby. Rapid wear occurs when a small amount of lubricant is used. If a part is broken, repair does not help, only a complete replacement is needed. You should not use the GAZ 66 front axle on the MTZ 80, there is a high probability of incompatibility.

Front axle diagram

The operation of gearboxes under any circumstances is associated with the presence of heavy loads. Only bevel gears do not need adjustment. This action is performed only when it is necessary to replace all parts or carry out major repairs.

The gear wears out because it takes on the load from the main parts. Because of this, after some time the teeth of the element wear out. This helps to increase the distance between the component elements. If the presence of such a condition is not taken into account for a long time, the likelihood of failure of the entire tractor increases. Tightening the union nut helps to adjust the design.

It is enough to secure repair parts such as bevel gears and bearings with a nut. When tightening, it is important to position the bearings correctly. Next, gradual rotation is performed until the position of the part is completely satisfied. After this, the fasteners are fixed in their final position upon completion of the main work.

It is assumed that a base sample will be used. The price for the MTZ 80 front axle remains unchanged regardless of the conditions.

Many craftsmen choose other tractor engines for installation. This allows you to find an economical replacement. The option is quite acceptable if there is complete confidence in compatibility. Otherwise, it is recommended to give preference to native structures. So repairing the front spoke will not be difficult.

Maintenance – simple but effective tips

It is no secret that repairing a unit is a rather lengthy and labor-intensive process, associated, among other things, with significant financial costs. Simple prevention can help avoid this, including:

• Maintain the oil level in the system at a level sufficient for normal operation of the device;
• Preventing oil overflow by unscrewing the plugs from the holes located in the lower part of the brake compartment every 60 hours of tractor operation;
• Lubrication of rear axle mechanisms and seasonal oil change during maintenance;
• The parking brake and planetary gear brake must be adjusted every 480 operating hours;
• Replace the brake pads in a timely manner and prevent complete wear.

List of components from the rear axle housing. Differential on MTZ-80

Parts diagrams are for reference only! We do not sell all rear axle housing parts. The differential for MTZ-80 is presented in this list. If there is a “Show prices” link in the right column, then these spare parts are from the “Rear Axle Housing” section. Differential" are for sale. Please refer to the product sheet for stock availability and price information. Show price" in the right column, we do not sell such parts and do not accept orders for them.

Common malfunctions that occur during PTO operation

• A fairly common problem when operating the MTZ-82 PTO is jamming of the shaft control lever, or difficult, with significant effort, control of the clutch driver. This occurs due to a malfunction of the reinforcement mechanism (spring cup), or wear of the claw coupling.
• Extraneous noises that are increasing, along with an increase in the transmitted torque, as well as traces of grease on the back cover indicate significant wear of the shaft splines, parts of the planetary gearbox, and possibly loss of elasticity or destruction of the cuffs.
• If the power take-off shaft is unusually noisy and jerky, then most likely the splined joints have become unusable. Or the teeth of the central gear have worn out (ground down). In this case, the shaft is pressed out and the condition of the gear is assessed. You will need to disconnect the rear axle and dog clutch. If a visual inspection shows significant gaps, or the gear moves completely freely, then the PTO requires serious repairs. After replacement, the shaft is mounted in place, and it must be adjusted.
• When the MTZ-82 tractor does not produce the required maximum power when working with attached equipment, the reason for this lies in the band brakes. They require appropriate adjustment or complete replacement. In cases where adjustment does not help to get rid of such a problem, there is a need to remove the PTO from the tractor and control the thickness of the brake bands. When the thickness has decreased to 2.5 millimeters and below, these worn bands are replaced with new ones.
• The PTO shaft moves too freely. This sign means that the tension on the locking nut has become loose. The power take-off shaft needs to be removed from the MTZ-82 tractor. The fixing nut must be tightened until it stops. And, if possible, restore the thread, or “cut a new one.”
• A visual inspection reveals significant oil leaks on the power take-off shaft cover. This is a common sign of a worn cuff or gasket. In such cases, the PTO of the MTZ-82 tractor must be dismantled and the gasket between the PTO cover and between the rear axle must be replaced. If a leak occurs from the shank side, then you need to remove the stopper ring, press out the shaft and replace the cuffs.

In all cases when, in order to correct malfunctions, the power take-off shaft needs to be separated from the tractor, to do this, you first need to unscrew the rear cover fastening bolts, and then press out the PTO assembly with technological bolts. After this, you need to remove the brake bands and check their thickness. As already indicated, the brake band requires replacement with a new one if its actual thickness is less than two and a half millimeters. Typically, significant wear of the brake bands is indicated by the continued rotation of the shaft end when the PTO is turned off, as well as by its uneven rotation.

In any cases where the speed reducer gearbox has been dismantled or dismantled, it is necessary to check or adjust the PTO. To do this, a jack is installed under the drive wheels of the MTZ-82 tractor. After which the power take-off shaft rotates, alternating engagement of various gears. When performing such an operation, the power take-off shaft of the MTZ-82 tractor must be switched to synchronous mode. While turning, the gear wheels should rotate freely.

Rear axle MTZ-80, 82

What does the rear axle of the MTZ tractor consist of? How can I adjust this? Tips for use.

In modern tractors, the rear axle is one of the most important components, the function of which is to transmit torque from the output shaft through the final drive and differential to the final drive along with the drive shafts used to install the hub on the transfer wheels. Today we will talk about what kind of device this is, the principle of its operation, the main problems of operation and maintenance.

Operating principle of the automatic differential lock (ADL) system

The automatic differential lock (ADL) system works as follows. The working fluid from the drain pipe 6 of the hydraulic booster, in which the pressure reducing valve 11 maintains a pressure of 0.8 MPa (8 kgf/cm2), flows to the blocking sensor tap. Further movement of the liquid depends on the position of the valve. When valve 4 is installed in the “On” position, the working fluid under a pressure of 0.8 MPa enters cavity A of the friction clutch, which blocks the differential crosspiece 13 with the left drive gear 12 of the final drive. When the tractor's guide wheels are turned at an angle of more than 8°, the power steering rack displaces spool 3, thanks to which the working cavity A of the clutch communicates with the power steering tank. Therefore, the pressure drops in cavity A of the clutch and the differential is unlocked. When the valve is set to the “Off” position, cavity A of the friction clutch is constantly, regardless of the position of the spool, in communication with the hydraulic booster tank and therefore the differential of the rear axle of the tractor is unlocked. Turning the automatic locking on and off is carried out by turning the flywheel 8 of the control valve. In the “Off” and “On” positions, the valve is fixed by ball 7, while mark 12 on the handwheel is set against the corresponding mark on sensor cover 9. The locking is activated only when there is significant slipping of the rear wheels of the tractor during field work and to overcome difficult areas when transporting goods. Operating the tractor with the differential lock constantly engaged on hard soils and roads is prohibited. With the lock turned on, the speed of the tractor when transporting goods should not exceed 10 km/h.

Malfunctions and causes of failure of the MTZ 82 front driving gear

A FDA failure is possible for two types of reasons: a malfunction of the FDA unit or a failure of the front axle mechanism itself.

Problems with the FDA drive

1. Malfunction of the transfer case, which does not allow power to be transferred to the intermediate drive support or interrupts the switching of FDA operating modes. The malfunction can be determined visually by the lack of rotation of the cardan shaft connecting the transfer case to the intermediate support, when the forced engagement of the FDA is turned on and the cardan is disconnected from the main shaft drive. Causes: unit malfunction or incorrect drive adjustment to enable FDA operating modes, wear or contamination of the transfer case mechanism.
2. Malfunction or incorrect adjustment of the clutch of the intermediate support of the FDA drive - accompanied by overheating of the unit and squeezing out boiled lubricant from the support housing through the seals. In this case, the transmission of torque from the support to the FDA main gear is interrupted or completely absent. This can usually be determined when driving under load with the drive axle engaged.

Drive transmission for the front axle MTZ 82

Causes of FDA failures

A common cause of FDA failures is wear or destruction of mechanism parts. The main factors influencing the wear rate are:

1. Insufficient lubrication of mechanisms due to improper control of the oil level in the axle housings, ignoring leaks and the entry of abrasive contaminants into broken unit seals.
2. Incorrect adjustment of clearances in the meshing of pairs of gears and rolling bearings of rotation bearings in the mechanism;
3. Excessive tensile and weight loads on the front axle, negatively affecting the axle mechanism.

The disadvantage of PVM MTZ 82 is the large number of joints with gaskets in the bridge structure. In relation to this feature, one of the main diseases of the unit is loss of lubrication. As a result, the upper bevel gears of the final drive often break.

Malfunction of the main drive of the bridge

Accompanied by a humming sound when the gearbox is operating and heating of the case above 60 ° C (checked to see if you can’t touch your hand for a long time). The reasons are violation of the permissible clearances in the rotation bearings, main gear gears and differential due to wear of the mechanism or incorrect adjustment. An indirect reason that affects the operation and condition of the main FDA gear pair is the condition of the cardan shaft joints and the general axial clearance of the shafts in the drive units, which creates axial runout on the FDA drive gear.

Malfunction of the axle differential

accompanied by noise during operation and overheating of the housing. The reasons are also the wear of fasteners. The absence of automatic differential locking indicates wear of the friction discs of the locking clutches built into the unit body. If the mechanism is not lubricated and the differential is overheated, the locking clutches may jam due to soldering of the discs.

Break in transmission of torque from the tractor axle shafts to the vertical shafts of the final drives

The causes of the malfunction are the coloring of the teeth of the upper bevel gear of the main gears, sticking of the vertical shaft bearings due to insufficient lubrication, wear of the splines in the lower part of the vertical shaft or its destruction. A vertical fracture of the shaft indicates unacceptable development of a pair of fingers - the bushing and tube of the finger. Check the transmission of rotation from the drive shafts to the side parts by looking through the open hatch of the upper bevel gear to see how the shaft of the main axle drive gear rotates.

Jamming of the kingpin in the final drive of the FDA

Accompanied by the inability to turn the steering wheel. The reasons are insufficient lubrication of the “rotary sleeve - rotary pipe” pair, as well as unacceptable wear of the pair and breakage of the rotary tube flange.

Main malfunctions of the automatic differential lock (ADL) system

The main malfunctions in which the automatic differential lock does not work are:

1. Spool 3 of the steering angle sensor is stuck. It is necessary to remove the sensor and wash it in clean diesel fuel or replace the sensor.
2. Low pressure of the working fluid in the pipeline to the lock-up clutch. It can be caused by a maladjustment of the pressure reducing valve or increased leakage of the working fluid in the sensor. In the first case, it is necessary to adjust the pressure reducing valve and caulk the valve seat, and in the second case, replace the sensor.
3. Unsatisfactory operation of the differential lock friction clutch. The clutch does not work well for two reasons: the clutch discs are oily or the friction linings of the clutch discs are worn out. In the first case, it is necessary to eliminate the leakage of working fluid and wash the clutch discs in gasoline, and in the second case, replace the friction linings with new ones.

Structure of the unit and its features

Tractor wheel hub

All mechanisms of the MTZ rear axle are enclosed in a single housing, made in the form of monolithic cast iron, the front part of which is equipped with fasteners for attaching the gearbox. The linkage bracket and the rear shaft gearbox, which is responsible for the power take-off, are attached to the rear. The openings on the side walls are equipped with gear-type transmission windows, brake linings and rear axle bushings, which are secured with steel bolts. The top of the casing is closed with a lid made of a solid steel sheet.

Main problems and dismantling the device

While the tractor is operating, excessive noise may occur during operation of the rear axle as a result of wear on system components or problems with gear engagement in the final drive. This is usually caused by excessive loads, lack of oil or improper installation of the unit. To diagnose the malfunction and its subsequent elimination, it is necessary to carry out the following operations:

• Measure the side clearances on the power train teeth;
• Check the oil level in the system;
• Determine the overall build quality of the device.

If there are gaps with an angle of more than 7 degrees, as well as defects and malfunctions in the differential or intermediate gears, malfunctions that cannot be eliminated by normal adjustment, the tractor is sent for maintenance, where the rear axle is disassembled, which includes the following intermediate steps:

• Removing the cabin with preliminary disassembly of other parts and elements of the tractor that interfere with this process;
• The division of its frame, carried out on a special rack, with the subsequent lifting of the rear wheels;
• Disabling elements directly interacting with the rear axle;
• Disassembling the unit and inspecting its parts.

Main types of breakdowns

Even with careful operation, the system periodically needs repairs. Malfunctions most often occur due to:

• spool jamming. To return the system to working condition, you need to remove the connection sensor and wash it thoroughly in diesel fuel. If the problem recurs regularly, it is better to replace the element with a new one;
• pressure drop in the drive. The cause of the malfunction is most often damage to the spring or jamming of the valve itself. Due to the fact that the element is collapsible, it can be adjusted directly on the stand. A drop in pressure can also occur due to fluid leakage through damaged gaskets. In this case, you cannot do without replacing the sensor;
• that the clutch is slipping. This occurs due to wear and oiling of the linings. Carefully disassemble the assembly and carefully inspect the discs. If the elements are coated with a layer of lubricant, they must be cleaned with a degreaser. When worn out, it is recommended to replace spare parts with new ones;

Important! Find and eliminate cracks through which fluid leaks. This will help reduce the frequency of cleaning and therefore reduce the likelihood of breakage.

• incomplete engagement of the clutch. Adjust the length of the rod, remove any play in the connections. If foreign objects or small stones get into the system, remove them.

Timely maintenance of the system guarantees a long service life of the locking system. With proper care, replacement of parts and cleaning, it works properly without creating problems for drivers or tractor owners.

Repair and adjustment of the rear axle MTZ 80

The rear axle of the Belarusian tractor has a fairly reliable design and, with proper care, can be used without major repairs for decades. The main reasons for failure: systematic overloads with slipping, frequent use of locks under load, insufficient lubrication. Premature clearances in gears, bearing units of shafts and gears due to wear of bearings and spline joints cause unacceptable vibrations of rotating parts. As a result, eccentricity occurs, which leads to a change in the color of the gear teeth, rapid breakage and wear of the seats, then jamming and complete failure of the mechanism. We recommend that you stop using the tractor if you hear any noise, buzzing or rubbing noise.

When deciding to stop a tractor for repairs, they are usually guided by the principle: “The sooner the machine is found and repaired, the cheaper it will be to repair the unit.”

To directly access the mechanism for diagnosing and repairing the lever mechanism, it is necessary to completely remove the tractor cabin, fuel tanks, hydraulic cylinder of the hitch, axle and the upper cover of the gearbox and drain the oil from the gearbox. A visual inspection shows the degree of wear of the mechanism components. When turning the gears, check the condition of the teeth with your finger (handle), check the play in the axles and hinge units, in the seats of the mechanism parts, in the gears and in the groove connections. Based on the identified problems, a decision should be made to disassemble the parts or components of the mechanism for detailed final detection of defects and subsequent replacement of parts.

Rear axle diagram MTZ 82 (80)

Installing the drive final drive gear

Correct installation of the bevel gear on the secondary gear shaft of the gearbox consists of three components: the optimal clearance in the bearing race on the shaft, the output of the gear on the shaft must be within the specified limits, the gear for tightening the nut must ensure the integrity of the shaft, the output shaft without axial play.

When installing the gear onto the gear shaft, tighten the locknut as much as possible. This eliminates axial play in the output shaft connection. The bearing shells are compressed by the support plate.

Sufficient bearing play is checked by applying torque to the gear, which is made as part of the output shaft without taking into account the bevel gear. The force should not exceed 6-7 Nm or 0.6-0.7 kgf. Reduce the tension on the bearing shells by placing a pair of 0.2mm and 0.5mm washers under the bearing bracket.

The bolts thread into ribs on the housing flange which, when tightened, push against the transmission housing and the housing retracts, reducing stress on the cage. Once sufficient clearance is achieved, plates of appropriate thickness are installed and the bowl flange is tightened with standard screws.

The clearance in the housing output shaft bearings should not exceed 0.3 mm. When assembling, please note that the distance from the outer surface of the gear to the outer surface of the gearbox housing should be 58 ± 0.15 mm. Insufficient power can be increased by placing washers under the gear.

Adjusting the main pair of MTZ 80 rear axle

When installing a gear into a main gear pair, two aspects must be considered: sufficient space in the gear and proper contact between the teeth of the pair.

Proper meshing of a pair of bevel gears

To achieve proper engagement and optimal contact surface, the gears must be positioned so that their conical shapes match. Adjustment of the lateral play in the clutch is carried out by selecting and installing adjusting plates between the flanges of the end shafts of the drive shafts and the axle housing, similar to adjusting the play of the differential bearings.

When installing a new angle gear, the gap should be between 0.25 and 0.55 mm. Check with a pressure gauge at three contact points equidistant between the gears. The gap can also be checked using a folded piece of newspaper, provided that the thickness of the newspaper is 0.1 mm. The gap is determined experimentally, taking into account the number of layers in which the teeth begin to cut through the layers of paper.

Correct adjustment is only achieved after adjusting the gearbox output shaft bearings. During normal operation of the main gearbox, a maximum distance of 2 mm is allowed. Reducing the backlash in this case is unacceptable, since the established working contact of the gears is disrupted, which can lead to torque jamming. To determine the contact point, draw some teeth on the gear and rotate the gear back and forth. Traces of paint on the teeth indicate the nature of the contact.

Mounting the contact surface in the main gearbox

The normal raceway occupies 50% of the working surface of the tooth and is slightly offset towards the narrow end of the tooth. If the contact is abnormal, the gear or sprocket must be replaced. A couple of gears cannot be disassembled; if the gear is damaged, the entire pair is replaced. Net side play adjustments and contact surface adjustments should only be made when assembling a new pair and not during operation.

Adjusting the differential bearings

The bearings are adjusted every 3000 operating hours, i.e. approximately every two seasons. An increase in backlash due to wear of teeth and bearings up to 0.3 mm leads to eccentricity and vibration of the mechanism. A sign of a malfunction is usually the appearance of noise and interference during operation. The adjustment is made by selecting seals with a thickness of 0.2 and 0.5 mm on the left flange of the main gear shaft.

Check the play with a pressure gauge by holding it close to the gear. The gear is rotary with a force of 50-60 kgf in the axial direction. The optimal bearing clearance should be 0.05 mm, and the acceptable clearance should be less than 0.1 mm. The permissible torque when rotating the differential, applied to the outer surfaces of the transmission gear teeth, should not exceed 30-50 Nm or 3-5 kg.m.

Since the sprocket is pressed against the right bearing, so as not to disturb the play in the main gear, adjustment is made by selecting spacers on the left side. To do this, disconnect the left brake drive rods and the oil line of the hydraulic system of the automatic locking mechanism. Then remove the automatic locking mechanism with the locking shaft and the left brake drum. Loosen the screws holding the left cup in place and press it down by threading the screws into the removal holes on the flange. This will provide access to the gaskets. Once the correct plate pack is installed, tighten the flange by rotating the differential until the bearing rollers are in the correct position.

Sources

• https://BashGazCrimea.ru/selhoztehnika/zadnij-most-mtz-80.html
• https://allautopark.ru/ustrojstvo-perednego-mosta-mtz-82-remont-zadnij-shema-blokirovka-bortovoj/
• https://dostavka99.ru/specnaznacheniya/zadnij-most-traktora.html
• https://prorastet.ru/selhozteznika/ustroystvo-zadnego-mosta-mtz-82-80-shema-remont-regulirovki