Do-it-yourself gas 53 lift repair

In detail: do-it-yourself repair of the gas 53 lift from a real master for the site my.housecope.com.

(097) 056-05-93, (099) 429-92-85, (093) 651-44-42

Repair of the hydraulic cylinder GAZ-53. Repair of the Hydraulic cylinder GAZ-SAZ. For repair of hydraulic cylinders, please call (097) 056-05-93. We work all over Ukraine.

The GAZ-53 hydraulic cylinder is an important component of the lifting mechanism of a dump truck. The truck is rightfully considered one of the most popular vehicles of the Soviet period. Such fame is due to the excellent qualities of this model, among which its practicality and reliability occupy a special place. By its structure, it is a side unloading truck.

Photo of the hydraulic cylinder GAZ-53

It is a similar design that is traditional and has been widely used in the CIS, which served as the starting point for the invention of various modifications. One of them is GAZ-SAZ 3507, which is a dump truck and, accordingly, has a special lifting mechanism. The hydraulics of the GAZ-53 have a rather complex structure and increasingly require repair work.

Photo of the hydraulic cylinder GAZ-SAZ 3507

The design of the hydraulic lift GAZ on yokes (on trunnions) and its elements

All in all, the GAZ-53 dump truck was no less popular than its progenitor. However, now it is less and less common to find a working version of this car. Over time, almost all of them have exhausted their strength limit and today are inactive.

Assembly drawing of the hydraulic cylinder GAZ-53, as well as its overall and connecting dimensions

This state of affairs is quite understandable, because the service life of any technical device is not unlimited, and even more so when it comes to mechanisms designed for lifting and transporting goods. Unfortunately, over the past years, it has almost completely exhausted itself, and the copies that are still functioning have gone through more than one repair. In terms of its structure, the GAZ-SAZ 53 lifting mechanism is of a hydraulic nature, and its principle of operation is based on the influence of a liquid that fills the system and creates the required pressure parameters.

Video (click to play).

Oil plays its role, and the diagram of the hoist device includes the following details:

4) Pressure relief valve (platform lowering)

6) Control valve fuse

9) Power take-off

10) Gear reverse gear box

Photo of the GAZ-53 platform lowering valve

Photo of the power take-off GAZ-53

As you can see from the above elements, the design of the GAZ 53 hydraulics has a rather complex structure. Each of these parts is a complete device, consisting of its own parts and structural elements. The principle of operation of the lifting mechanism lies in the functioning of the GAZ-53 hydraulic cylinder. In turn, it has a telescopic structure, consisting of 3 equivalent sliding parts.

To ensure the operation of the lift, they are filled with oil, which is supplied to them by a pump. In the same way, to lower it, the liquid leaves the GAZ-53 hydraulic cylinder through the check valve. Such a process makes it possible to ensure the full operation of the platform and significantly facilitate human labor.

Repair of the hydraulic cylinder GAZ-53

The GAZ-SAZ 53 dump truck was produced in 2 versions: with side and vertical unloading. The principle of operation of hydraulics has always remained unchanged and consisted in supplying oil using a power take-off unit through a pump in the cavity of the lift. The hydraulic cylinder for lifting the body of the GAZ-53 provided all the necessary actions. It is not surprising that it most often fails, since almost all the load falls on it.This state of affairs affects the overall functionality of the lift, since it completely breaks down. To restore its working capacity, it is necessary to carry out a whole range of measures that can only be performed by a true master of his craft.

Photo repair kit for hydraulic cylinder GAZ-53

It follows from this that the repair of the GAZ-53 hydraulic cylinder is a rather complicated and time-consuming process, which includes many directions, from replacing the lubricating fluid to replacing the plungers. In general, when carrying out restoration work, the following elements may need to be replaced:

1) O-rings (RTI)

The most common cause of breakdown when lifting the GAZ-53 body is the leakage of sealing elements designed to provide pressure build-up in the system. In turn, a violation of the integrity of the hydraulics and oil leakage contribute to a decrease in pressure indicators. This causes the lift to malfunction and be unable to operate at full capacity. Sometimes situations arise related to the violation of the integrity of any part.

In such a case, repairing the hydraulic cylinder requires a complete replacement of the damaged element. This categorization is due to the fact that working with cargo in this state of affairs becomes completely ineffective, but also extremely dangerous. This is quite simple to do: by opening the drain hole, which is located at the bottom of the device. Only then can you start troubleshooting. For this, the entire system is almost completely disassembled, and all its parts must be cleaned. In general, it is possible to reanimate the GAZ-53 hydraulics. However, for this you need not only have extensive experience as a mechanic, but also have a lot of spare parts in stock, since it is quite difficult to get them in good condition on the modern market.

The hydraulic lift GAZ-53 consists of many different elements that create a single mechanism that makes it possible to significantly facilitate the transportation and unloading of goods. At the same time, due to the high degree of functional wear, such mechanisms quite often fail.

GAZ-53 body lifting scheme

In order to repair them, it is necessary to perform a great variety of different operations. This requires an excellent knowledge of the design of the device and experience with similar units. This is the only way to carry out a full repair and completely restore the operation of the hydraulic lift.

If you do not have the time or opportunity to repair the GAZ-53 hydraulic cylinder, then just entrust it to our specialists by calling (097) -056-05-93.

The GAZ-53 hydraulic cylinder is an important component of the lifting mechanism of a dump truck. The GAZ 53 truck is rightfully considered one of the most popular cars of the Soviet period. Such fame is due to the excellent qualities of this model, among which its practicality and reliability occupy a special place. By its structure, it is a side-loading truck.

It looks like a hydraulic cylinder for lifting the body of the GAZ 53

At one time, the GAZ-53 dump truck was no less popular than its progenitor. However, now it is less and less common to find a working version of this car. Over time, almost all of them have exhausted their strength limit and today are inactive.

Dimensional drawing of the structure of the hydraulic cylinder of the body Gas 53

Oil plays its role, and the diagram of the hoist device includes the following details:

storage tank;
oil filter;
hydraulic cylinder;
platform lowering valve;
control valve;
control valve fuse;
check valve;
gear pump;
power take-off;

It looks like a power take-off Gas 53

The principle of operation of the lifting mechanism lies in the functioning of the GAZ-53 hydraulic cylinder. In turn, it has a telescopic structure, consisting of 3 equivalent sliding parts.

This state of affairs affects the overall functionality of the lift, since it completely breaks down. To restore its working capacity, it is necessary to carry out a whole range of measures that can only be performed by a true master of his craft.

A set of rubber bands for repairing the hydraulic cylinder GAZ-SAZ 53

sealing rings;
stock;
hydraulic piston;
plungers.

The most common cause of breakdown when lifting the GAZ-53 body is the leakage of sealing elements designed to provide pressure build-up in the system.
In turn, a violation of the integrity of the hydraulics and oil leakage contribute to a decrease in pressure indicators. This causes the lift to malfunction and be unable to operate at full capacity.
Sometimes situations arise related to the violation of the integrity of any part.

An example of the work of the hydraulic cylinder for lifting the body of GAZ 53

Full lineup: GAZ-3307, 53, GAZ-3309, GAZ-66, 3308, 33081, 33086, GAZ-33104

Hydraulic lifting device for GAZ-SAZ-3507/35071 dump trucks on the GAZ-3307/3309 chassis

The tipper platform is tilted by means of a hydraulic cylinder. The schematic diagram of the hydraulic tipping device is shown in fig. one.

The tipping mechanism of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307/3309 chassis provides lifting and lowering of the platform, stopping it in any intermediate position, limiting the pressure in the hydraulic system to no more than 115 - 120 kgf / cm2.

Rice. 1 - Schematic diagram of the hydraulic tipping device of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307/3309 chassis

1 - oil tank; 2 - drain strainer with a safety valve; 3- oil tank filler neck; 4 - pusher of the platform lowering valve; 5 - hydraulic cylinder; 6 - platform lowering valve; 7 - control valve; 8 - safety valve of the control valve; 9 - check valve; 10 - gear pump; 11- PTO control lever; 12 - power take-off box; 13 - gear wheel of reverse gear of the car gearbox;
14 - KU control lever

Hydraulic system of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307/3309 chassis

The hydraulic system of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis is controlled by two levers - the PTO control lever 10 and the KU control lever 13 (Fig. 2).

They are installed in the driver's cab to the right of the gear lever. The PTO control lever has two positions: the extreme forward "lift" and the extreme rear "neutral". The KU control lever also has two positions - the extreme forward "neutral" and the extreme rear "lowering".

To tilt the platform, it is necessary to move the PTO control lever to the extreme forward position (in the direction of the vehicle) with the engine on and the clutch disengaged.

Fig. 2 - Power take-off with oil pump and control valve of the GAZ-SAZ-3507/35071 dump truck

1 - ball head; 2 - power take-off box with pump, crane and branch pipes; 3- arm bracket; 4 - KU pusher drive mechanism; 5 - bolt or hairpin; 6 - conical washer; 7 - hatch cover gasket; 8, 20, 21 - fingers; 9 - spring; 10 - PTO control lever; 11- plank; 12- finger; 13- KU drive lever; 14 - bolt 15, 16, 17 - washers; 18, 19 - cotter pins.

After engaging the clutch of the GAZ-SAZ-3507/35071 dump truck, the power take-off with an oil pump is switched on, and oil from the oil tank will begin to flow through the suction line into the oil pump, and from there under pressure through the pressure line into the hydraulic cylinder. Under the influence of the increasing oil pressure, the hydraulic cylinder plungers will begin to extend, causing the platform to overturn.

The increase in pressure in the hydraulic system after the end of the working stroke of the hydraulic cylinder, as well as when overloading the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis is limited by the 15 KU safety valve (Figure 6), which, opening at a pressure of 115-120 kgf / cm2, connects the discharge cavity H with the drain cavity C.

To lower the platform, disengage the clutch, move the PTO control lever 10 (Figure 2) to the rearmost position. This will turn off the pump. Move the lever 13 (Figure 2) of the KU control also to the extreme rear position.

In this case, the pusher 6 will move (Figure 6), opening the valve 1 for lowering the platform of the GAZ-SAZ-3507/35071 dump truck. As a result, the discharge line is connected to the drain line, and the oil from the hydraulic cylinder, under the action of the platform mass, will flow through the filter into the oil tank.

If it is necessary to stop the empty platform in an intermediate position, it is enough to move the control lever to the extreme forward position. At the same time, due to the presence of valve 1 in the KU (Figure 6) lowering the platform and the check valve 22, the discharge line is blocked, which causes the platform to stop lowering.

Power take-off with oil pump and control valve of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis

The power take-off (PTO) GAZ-SAZ-3507/35071 on the GAZ-3307 / GAZ-3309 chassis is used to transfer power from the engine (through the gearbox) to the oil pump. It is attached to the gearbox housing on the right side with bolts, studs and nuts with lock washers. Between the flanges of the PTO and the gearbox, a 0.8 mm thick paronite gasket is installed.

The power take-off (Fig. 3) contains a crankcase 1 in which the drive gear 10 and the driven gear 4 are located on the ball bearings 3 and 12, the axis 9 of the drive gear and a locking device consisting of a locking ball 14 and a spring 16.

Rice. 3 - Power take-off box 3507-01-4201010 GAZ-SAZ-3507/35071 on the chassis GAZ-3307 / GAZ-3309

1 - power take-off case; 2, 11, 13 - retaining rings; 3, 12 - ball bearings; 4 - driven gear; 5 - rubber sealing ring; 6 - gland washer; 7 - stuffing box frame; 8 - stuffing box; 9 - the axis of the driving gear; 10 - a leading gear wheel; 14 - locking ball; 15 - plug; 16 - spring of the locking ball; 17 - gasket; 18 - bolt; 19 - washer; 20 - bearing cover; 21 - persistent ring

Ball bearings 12 are fixed on the drive pinion axis 9 by two locking rings 13, on which the drive gear 10 rotates freely, kept from lateral movements by a retaining ring 11. The drive gear is in constant meshing with the reverse gear of the car's gearbox.

To prevent oil leakage from the crankcase 1 through the holes under the axle 9 of the drive gear, a rubber ring 5, an oil seal 8 are placed on one side and the oil seal frame 7 is pressed in, on the other side the hole is closed with a plug 15.

With the help of the control lever 10 of the KOM GAZ-SAZ-3507/35071 (Figure 2), pivotally connected to the axis 9 of the drive gear (Figure 3), the axis 9 moves in the bores of the KOM housing in the axial direction and thereby engages (or disengages) gearing) drive gear 10 with driven gear 4.

In the position shown in Figure 14, the drive gear 10 is not in mesh with the driven gear 4 - the drive is off. The extreme positions of the axle 9 are fixed by a locking ball 14, which, under the action of the spring 16, enters the annular grooves of the axle.

The oil pump of the hydraulic system of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis

Gear pump NSh (Figure 4) consists of a housing 1, a cover 2 and a pumping unit, which includes: driven 3 and drive 4 gears, two pairs of bushings 5 and 6, two compensators 7, two cuffs 8.

The joint between the body and the cover is sealed with a rubber O-ring. The cover is attached to the body with eight bolts 10, under the heads of which spring washers 11 are placed.

Fig. 4 - Oil pump of the hydraulic system GAZ-SAZ-3507/35071

1 - case; 2 - cover; 3 - driven gear; 4 - driving gear; 5, 6 - bushings; 7 - compensator; 8 - cuff; 9 - a sealing ring; 10, 11 - bolt and spring washer; 12 - cuff; 13 - retaining ring; 14 - support ring

To reduce internal oil leakages in the hydraulic system pump of the GAZ-SAZ-3507/35071 dump truck through the gaps between the end surfaces of the gears and compensators, automatic control of the gap values at the ends of the gears was applied, which occurs by pressing the compensators to the ends of the gears with oil under pressure from the pressure side in cavity B.

Both expansion joints are "floating" (self-aligning), i.e. are pressed against the ends of the gears independently, which ensures uniform running-in of the working planes of the expansion joints. Oil seeping through the lubrication grooves of the bushings enters through the channel at the bottom of the housing and through the channels in the cover and driven gear into the cavities connected to the suction chamber.

Thus, all oil leaks are directed to the suction line of the pump. The drive end of the drive gear shaft is sealed with a rubber reinforced collar 12. To prevent the collar 12 from being squeezed out, a retaining ring 13 and a support ring 14 are installed.

When a pair of gears rotate, the oil enters through the “Entrance” outlet into the interdental space, and then is pumped through the “Exit” inlet into the hydraulic system of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis.

The oil pump is installed in the spline hole of the driven gear and is attached to the PTO flange (Figure 2 and 3). Between the flanges of the PTO and the oil pump, a 0.8 mm thick paronite gasket is installed. The suction and discharge cavities of the oil pump are in communication with the cavities of the oil tank and the WHB.

Hydraulic cylinder of the platform of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis

A telescopic hydraulic cylinder with three retractable plungers is used to lift the platform. The device of the hydraulic cylinder is shown in Figure 5.

Figure 17 - Hydraulic cylinder 3507-01-8603010-01 of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis

1 - upper support heel; 2, 3, 4 - plunger; 5 - bottom; 6 - high pressure hose; 7 - lower ball joint; 8 - case; 9– support cover; 10 - upper ball joint; 11, 12, 13, 14 - sealing rings; 15, 16, 17 - protective rings; 18, 19 - retaining rings; 20 - lower support heel

The oil is supplied to the hydraulic cylinder of the GAZ-SAZ-3507/35071 dump truck through a fitting in the bottom. To seal plungers 2, 3, 4, body 8 and bottom 5, O-rings 11, 12, 13, 14 are used. To protect the friction surfaces of the plungers from dust and dirt, rubber protective rings 15, 16, 17 are installed in the plungers.

To limit the downward movement of the plungers, spring retaining rings 18, 19 are installed in the lower part of the plungers.

The hydraulic cylinder has two ball heads installed in the upper 1 and lower 20 support feet and fixed in them by means of covers 9 with bolts and spring washers. The upper and lower bearings are lubricated - during installation in case of repair or replacement of the hydraulic cylinder.

Control valve, pipelines and oil tank of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis

The control valve of the GAZ-SAZ-3507/35071 dump truck (Figure 6) is used to control the lifting and lowering of the platform. The control valve is a unit that combines three valves: a check valve 22, a platform lowering valve 1 and a safety valve 15.

The check valve 22 serves to prevent spontaneous lowering of the raised platform when the pump is not running. The platform lowering valve 1 is designed to bypass fluid from the hydraulic ram to the oil tank when the platform is lowered.

Figure 16 - Control valve of the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis

1 - platform lowering valve; 2, 12, 16, 23 - sealing rings; 3 - washer; 4 - stuffing box frame; 5 - stuffing box; 6 - pusher; 7 - lock nut; 8 - safety valve slider; 9 –adjusting screw; 10 - filling; 11 - wire; 13, 18, 19 - springs; 14 - safety valve mandrel; 15 - safety valve; 17 - cork; 20 - check valve mandrel; 21 - check valve seat; 22 - check valve; 24 - mandrel of the lowering valve; 25 - case

Safety valve 15, adjusted to a pressure of 115 - 120 kgf / cm2, is used to unload parts and assemblies of the tipping device and platform when overloading over the rated capacity. The seals are made with rubber rings.

High and low pressure pipes and rubber hoses are used as pipelines for supplying oil to the hydraulic system units on the GAZ-SAZ-3507/35071 dump truck on the GAZ-3307 / GAZ-3309 chassis.

The high-pressure hose is a rubber hose in accordance with GOST 6286-73 (inner diameter - 12 mm, outer diameter - 25 mm), the ends of which are embedded in metal fittings.

High pressure tubing is made of steel tubing with ferrules welded to them. All hoses and high pressure pipes are connected to each other using choke connections. Tightness in the nipple joints is achieved by tightening the ball surface of the nipple into the tip cone.

Low pressure pipes for the hydraulic system of the GAZ-SAZ-3507/35071 dump truck are made of steel pipes. The low-pressure rubber hoses are connected to the low-pressure pipes by means of band clamps. Oil tank 1 (Figure 1) is a stamped-welded structure made of thin sheet steel.

In the lower part of the oil tank there is a drain hole closed with a plug and a branch pipe for connecting the piping to the pump, and in the upper part there is a drain oil filter bolted to the oil tank housing. The filter inlet is connected to the drain cavity of the control valve.

The drain filter has filter elements, consisting of filter nets, and a safety valve, which is triggered at a pressure of 3-5 kgf / cm2, which lets oil into the tank in case of clogging of the filter elements.

At the first oil change (after 1000 km of run of the GAZ-SAZ-3507/35071 dump truck), and later at TO-2, it is necessary to thoroughly rinse the filter elements of the filter. The top of the tank has an oil filler neck with a strainer. The neck is closed with a plastic cap made in one piece with the oil indicator.

The oil gauge is made in the form of a stepped rod, the collar of which serves as an indicator of the maximum permissible level, and the end of it serves as an indicator of the minimum permissible liquid level. It is not allowed to exceed the oil level above the maximum and decrease below the minimum level.

The communication of the oil tank cavity with the atmosphere occurs through an opening in the neck. Oil tank 5 (Figure 7) is fixed on brackets to the front beam of the overframe device.

To assemble the engine, as well as to disassemble it, the engine block assembly with the clutch housing is fixed on the stand (see Fig. 1).

Before assembly, all engine parts are sized, washed thoroughly, blown with compressed air and wiped with clean napkins. All threaded connections (pins, plugs, fittings, etc.), if they were twisted during disassembly or were replaced, must be placed on red lead or lead whitewash diluted with natural drying oil.

One-piece connections (plugs of the block and cylinder heads) are placed on nitro lacquer.

To be installed on a repaired engine not allowed:

- used cotter pins and cotter wires;

- spring washers that have lost their elasticity;

- bolts and studs with extended thread;

- nuts and bolts with worn edges;

- parts with more than two nicks or dents on the thread, or torn threads;

Assemble the engine in the reverse order of disassembly.

Below are specific recommendations and additional requirements for engine assembly.

When replacing cylinder liners, before installing, the liner is selected according to the socket in the cylinder block.

Liners are selected using an accurate metal ruler and a set of probes as follows:

- the liner, installed in its place in the cylinder block without gaskets, must sink against the cylinder block mating surface.

The ruler is installed on the mating surface, and the probe is inserted into the gap between the ruler and the end of the sleeve (Fig. 2).

The thickness of the gasket is chosen so that after installing the liner with the gasket, it will rise above the surface of the cylinder block within the range of 0.02-0.09 mm.

Sealing gaskets are available in various thicknesses:

0.3; 0.2; 0.15 and 0.1 mm. Depending on the gap, one or another gasket is put on the cylinder liner, sometimes the required value is obtained by a set of gaskets of various thicknesses.

After installation in the cylinder block, the liners are secured with clamping sleeves (see Fig. 3).

As a rear oil seal on engines, an asbestos cord impregnated with an oil-graphite mixture is used. A cord with a length of 140 mm is laid in the sockets of the cylinder block and the gland holder. Using the device, the cord is crimped in its sockets with light hammer blows, as indicated in Fig. 4. Without removing the device, cut the ends of the cord flush with the plane of the gland holder connector. The cut must be even, no loose ends and uneven cut are allowed.

When assembling the crankshaft with flywheel and clutch, the following requirements are met.

The flywheel mounting nuts are tightened, providing a torque of 7.6-8.3 kgm.

When assembling the clutch, the driven disc is mounted with a damper to the pressure plate and centered on the crankshaft bearing (the gearbox drive shaft can be used as a mandrel).

Marks "O", embossed on the casing of the pressure plate and the flywheel near one of the holes for the casing mounting bolts, must be aligned.

The crankshaft, flywheel and clutch assembly must be dynamically balanced. Allowable imbalance is 70 Gsm.

When balancing, remove excess weight from the heavy side by drilling the flywheel metal at a distance of 6 mm from the ring gear with a drill 8 mm in diameter to a depth of no more than 10 mm.

If the imbalance of the assembled shaft exceeds 180 Gsm, the shaft is disassembled and each part is balanced separately. Flywheel imbalance should not exceed 35 Gsm; imbalance of the pressure plate assembly with the casing - 36 Gsm; The imbalance of the driven disk is 18 Gsm.

Main bearing caps set so that the fixing protrusions of the liners are on one side, and the numbers or marks embossed on the covers correspond to the numbers of the beds. When installing the front cover, it is necessary to ensure that the locking tab of the rear thrust bearing washer enters the groove of the cover, and that no steps are formed between the end of the cover and the end of the cylinder block.

Tighten the nuts securing the main bearing caps (torque 11-12 kgm). After tightening and splitting the nuts of the main bearing caps, the crankshaft should rotate easily with little effort.

After pressing the crankshaft gear (Fig. 5) using a puller and a thrust sleeve, check the axial clearance of the crankshaft, for which press the crankshaft to the rear end of the engine and use a feeler gauge to determine the gap between the end of the rear thrust bearing washer and the end of the front main journal of the crankshaft (fig. 6). The gap should be between 0.075 - 0.175 mm.

When assembling the parts of the connecting rod-piston group, the following requirements must be observed.

Piston pins are selected to the connecting rods so that at room temperature (+18 0 C) a slightly lubricated finger smoothly moves in the connecting rod hole under a slight effort of the thumb.

Before assembly, the pistons are heated in hot water to +70 0 С.

Pressing a pin into a cold piston is not allowed, as this can lead to damage to the surfaces of the piston pin bore holes, as well as to deformation of the piston itself.

Connecting rods and pistons when assembling, they are oriented as follows: for the pistons of the first, second, third and fourth cylinders, the inscription on the piston "in front" and the number stamped on the connecting rod should be directed in opposite directions, and for the pistons of the fifth, sixth, seventh and eighth cylinders - in one side (fig. 7).

The piston pin retaining rings are installed in the grooves of the piston bosses so that the tendril bend is directed outward.

Piston rings are selected according to the sleeves in which they will work. The gap, measured at the joint of the ring, laid in the sleeve, should be in the range of 0.3-0.5 mm for compression and oil scraper rings. In the upper piston groove, a chrome-plated one is installed, and in the second - a tin-plated compression ring with a groove on the inner side to the bottom.

Before installing the piston ring joints in the cylinder liners, place the piston ring joints at an angle of 120 ° to each other, and protective brass caps should be put on the connecting rod bolts to avoid accidental damage to the connecting rod journal surface.

When installing pistons in cylinder liners, make sure that the inscription on the piston "in front" is directed towards the front end of the cylinder block. Tighten the connecting rod bolt nuts (torque 6.8 - 7.5 kgm) and lock.

After pressing the gear onto the camshaft (Fig. 8), check the axial clearance between the thrust flange and the end of the camshaft gear with a feeler gauge. The gap should be between 0.08 - 0.2 mm.

To assemble the engine, as well as to disassemble it, the engine block assembly with the clutch housing is fixed on the stand (see Fig. 1).

One-piece connections (plugs of the block and cylinder heads) are placed on nitro lacquer.

To be installed on a repaired engine not allowed:

- used cotter pins and cotter wires;

- spring washers that have lost their elasticity;

- bolts and studs with extended thread;

- nuts and bolts with worn edges;

- parts with more than two nicks or dents on the thread, or torn threads;

Assemble the engine in the reverse order of disassembly.

The preparation of parts for assembling the engine can be found in the article - Preparation of units and parts for assembling the ZMZ-53 engine

Below are specific recommendations and additional requirements for engine assembly.

When replacing cylinder liners, before installing, the liner is selected according to the socket in the cylinder block.

Liners are selected using an accurate metal ruler and a set of probes as follows:

- the liner, installed in its place in the cylinder block without gaskets, must sink against the cylinder block mating surface.

The ruler is installed on the mating surface, and the probe is inserted into the gap between the ruler and the end of the sleeve (Fig. 2).

The thickness of the gasket is chosen so that after installing the liner with the gasket, it will rise above the surface of the cylinder block within the range of 0.02-0.09 mm.

Sealing gaskets are available in various thicknesses:

0.3; 0.2; 0.15 and 0.1 mm. Depending on the gap, one or another gasket is put on the cylinder liner, sometimes the required value is obtained by a set of gaskets of various thicknesses.

After installation in the cylinder block, the liners are secured with clamping sleeves (see Fig. 3).

As a rear oil seal on engines, an asbestos cord impregnated with an oil-graphite mixture is used. A cord with a length of 140 mm is laid in the sockets of the cylinder block and the gland holder.Using the device, the cord is crimped in its sockets with light hammer blows, as indicated in Fig. 4. Without removing the device, cut the ends of the cord flush with the plane of the gland holder connector. The cut must be even, no loose ends and uneven cut are allowed.

When assembling the crankshaft with flywheel and clutch, the following requirements are met.

The flywheel mounting nuts are tightened, providing a torque of 7.6-8.3 kgm.

When assembling the clutch, the driven disc is mounted with a damper to the pressure plate and centered on the crankshaft bearing (the gearbox drive shaft can be used as a mandrel).

Marks "O", embossed on the casing of the pressure plate and the flywheel near one of the holes for the casing mounting bolts, must be aligned.

The crankshaft, flywheel and clutch assembly must be dynamically balanced. Allowable imbalance is 70 Gsm.

When balancing, remove excess weight from the heavy side by drilling the flywheel metal at a distance of 6 mm from the ring gear with a drill 8 mm in diameter to a depth of no more than 10 mm.

If the imbalance of the assembled shaft exceeds 180 Gsm, the shaft is disassembled and each part is balanced separately.

Flywheel imbalance should not exceed 35 Gsm;

imbalance of the pressure plate assembly with the casing - 36 Gsm;

The imbalance of the driven disk is 18 Gsm.

Tighten the nuts securing the main bearing caps (torque 11-12 kgm). After tightening and splitting the nuts of the main bearing caps, the crankshaft should rotate easily with little effort.

On dump trucks, lifting mechanisms are used with a hydraulic drive from the vehicle engine.

In this case, two variants of the design of the lifting mechanism are possible: - with swinging cylinders and articulated connection of the rods with the bottom of the body platform; - with oscillating cylinders and a lever-balancing system of influence on the body platform.

When the lifting mechanism is operating (Fig. 18.13), part of the engine power (through the power take-off, oil pump, control valve, check valve, lifting mechanism cylinder) is transferred to the platform of the dump truck body.

Power take-off g transfers torque from the vehicle's gearbox to the hoist oil pump. The power take-off g is attached to the gearbox hatch on the right-hand side. The drive shaft, together with the drive gear, moves forward or backward in the power take-off housing using the lever for engaging and disengaging the lifting mechanism. When the drive shaft is moved to the right (in the figure, the lever is in position), the gear engages with the gear of the gearbox reverse gear block, in which the gear shift lever should be in the neutral position.

The pinion of the drive shaft, having constant engagement with the driven gear, transfers rotation from the reverse gear of the gearbox to the drive shaft of the oil pump. The latter has a splined connection by means of a sleeve with a driven gear of the power take-off.

The gear-type oil pump has a device similar to that of an oil pump for a lubrication system of an automobile engine.The pump provides working pressure in the hydraulic system of the lifting mechanism up to 8 MPa.

The control valve B allows raising and lowering the body platform and, if necessary, fixing it in intermediate positions. It is installed on the upper platform of the oil pump casing e. In the valve casing, the spool is moved by means of a rod, which is connected to the power take-off lever. In this case, the spool, occupying a different position in the valve body c, communicates the oil supply channel from the oil pump d with a channel, the continuation of which is the high pressure pipeline. Through this pipeline, oil is pumped into the cylinder a of the lifting mechanism. In another position, the control valve spool communicates with the oil drain channels to the oil tank.

Rice. 18.13. The lifting mechanism of the ZIL-MMZ-555 dump truck:
a — cylinder; b - oil tank; в - control valve; g - power take-off; I - position of the power take-off lever when lifting the platform; II — neutral position; III - position when lowering the platform

The check valve closes the oil drain channel to the oil tank when the oil pump is not running with the body platform in the upper or intermediate position. The safety valve is triggered if the pressure in the hydraulic system of the lifting mechanism exceeds 9 MPa.

The cylinder of the lifting mechanism (Fig. 18.14) is pivotally attached to the subframe through the trunnions, which is necessary to increase the rigidity of the dump truck frame. The subframe, in turn, is hinged to the body platform. The cylinder body contains a sleeve sealed with rubber and protective rings, the inner surface of which is a guide for the plunger. For fixed movement of the liner relative to the cylinder body, guide liners are installed, and for fixed movement of the plunger relative to the liner, guide liners are installed.

The cylinder is closed from below with a bottom with sealing rubber and retaining rings and has a drain plug. The plunger is connected to the axle by means of a bracket, which is located in the brackets of the cross beams of the body platform. The axis with the bracket is in the same plane with the trunnions (in Fig. 18.14, the axis and the bracket relative to the trunnions are conventionally rotated 90 °).

Rice. 18.14. Lifting cylinder

Oil is supplied to the cylinder by an oil pump d through a control valve b and a high pressure pipeline. The pipeline is connected by means of a sleeve and a union to the right journal of the cylinder, in which there is a channel. The cavity under the plunger bottom is filled with oil, and at a pressure of 7-8 MPa, the plunger begins to move upward (the platform rises). When the protrusions of the lower part of the plunger rest against the thickened upper part of the liner, the joint movement of the plunger and the liner will begin. The movement stops when the liner projections are in contact with the cylinder body projections.

Pivot connections to the body platform and subframe of the tipper vehicle allow the cylinder to change its angle of inclination.

The oil tank (see Fig. 18.13), stamped from sheet steel, is located between the cylinder a and the oil pump e. Through the drain pipe branch pipe oil from the cylinder a through the pipeline and the control valve in returns to the oil tank.

At the top of the tank there is a filler neck with a plug and an oil measuring rod, and at the bottom there is a drain hole closed with a plug. When returned, the oil is cleaned in a filter. To prevent agitation of the oil, a baffle and a reflector are installed inside the tank.

The pipelines connecting the cylinder a, oil tank, pump d and control valve c are steel pipes and rubber hoses. For the high-pressure pipeline, steel pipes with a wall thickness of 3 mm and rubber hoses with a wall thickness of 6 mm with double metal braids are used.For low-pressure pipelines, steel pipes with a wall thickness of 1.5 mm and hoses made of cushioning fabric with a wall thickness of 5-6 mm are used.

The body platform (Fig. 18.15) is a welded structure made of steel and has longitudinal and transverse beams. The shape of the platform can be rectangular, trough-shaped (semi-cylindrical) and bucket-shaped, taking into account the specialization of the dump truck. So, for the transportation of soil and gravel, trough-shaped or semi-cylindrical platforms are used. For transporting solutions, it is better to have a rectangular platform. The platform is lifted by a hydraulic lift attached to the subframe and platform using a bracket. The subframe has a bracket for attaching a mudguard, a bracket for a gas tank, etc.

The platform longitudinal beams are connected to the rear ends of the subframe using axles. When the platform is raised, a semi-automatic mechanism for controlling the tailgate locks is triggered, which has hinges in the platform brackets. In the horizontal position of the body, the cam of the locking mechanism enters the slot of the subframe bracket. When the platform is raised, the cam, sliding along the bracket, turns, and with it the shaft with the handle turns. On the shaft there are eccentrics with a bracket. The rotation of the eccentrics is accompanied by the movement of the bracket back together with the rod moving in the guide bracket.

When moving backwards, the pull pushes the locking hook, which rotates relative to the pin, and the tailgate opens under its own weight (when the platform is raised). To close the tailgate, when the platform after unloading takes a horizontal position, the driver needs to get out of the cab and turn the shaft using the handle. In this case, the cam enters the slot of the bracket and keeps the platform from lifting when the dump truck is moving. The tailgate is held in the closed position by means of locking hooks, platform brackets.

Rice. 18.15. Body platform: A - position of the units of the front and rear mechanisms with the tailgate closed; B - position with the tailgate open

When servicing and repairing units that can be accessed in the raised position of the platform, it is imperative to place a stop that is pivotally connected to the left longitudinal beam of the subframe.

When lifting the platform (Fig. 18.16) of the body, the power take-off lever is moved to the rearmost position and the oil from the oil pump enters the channel to the control valve, opening the check valve, and then through channel b and the high pressure pipeline to cylinder 3 of the lifting mechanism. When the platform reaches its end position or to stop the platform in any position, the power take-off lever is moved to the neutral (middle) position. The oil pressure check valve closes the channel in the control valve.

To lower the platform, the power take-off lever is placed in the extreme forward position, while the control valve spool moves to the right, the channels communicate with each other and the oil returns from the cylinder to the oil tank.

Rice. 18.16. The scheme of the hydraulic system of the lifting mechanism: a - channel for supplying oil to the oil tank; b - channel for supplying oil to the cylinder; c - oil supply channel from the pump to the control valve; g - drainage channel; e - oil bypass channel 1 - valve spring; 2 - safety valve; 3 - lifting mechanism cylinder; 4 - oil tank; 5 - power take-off lever; 6 - pipeline for returning oil from the control valve to the oil tank; 7 - control valve body; 8 - oil pump; 9 — pipeline for supplying oil from the tank to the pump; 10 — pipeline for pumping oil into the cylinder of the lifting mechanism; 11 — check valve; 12 — spool; 1 — lifting the platform; II — stopping the platform; 111 — lowering the platform

Video (click to play).

The body platform can, during unloading, tilt not only backwards, but also to the right or left thanks to the articulated joints with the subframe and the locking mechanism (for opening the side walls). In this case, the cylinder of the lifting mechanism should have four pins for tilting in mutually perpendicular planes. The design of the lifting mechanism is somewhat more complicated, but this is offset by savings in loading or unloading goods in conditions of small maneuvering areas.

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