Civil and military bridge UAZ. What's the difference?

Starting from the very first models, all cars of the Ulyanovsk Automobile Plant had a 4 x 4 wheel arrangement and had high cross-country ability on all types of roads. Naturally, the legendary UAZ-3303 is also an all-wheel drive van, the basis of its chassis is the front and rear axle.

The design of the front axle of the UAZ “Bukhanka” is a little more complicated than the rear one, since it is the drive axle and plays an important role in driving the car.

Why are bridges needed and what types of bridges are there on UAZ?

In addition to the fact that the front axle provides control of the car, it has several other important functions:

• it transmits and distributes torque to the front wheel pair, providing high cross-country ability;
• transmits the reaction of the support from the wheels that are in contact with the road to the body;
• transfers the inertial force that occurs in the body when the car is moving to the wheels.

In fact, all of the above, except for driving the car, is also done by the rear axle of the UAZ “Bukhanka”.

Today, the Ulyanovsk Automobile Plant installs 3 types of bridges on its cars, which differ in both design and technical characteristics:

• A bridge of the “Timken” type, which has a single-stage final drive, or “civilian”.
• With final drive, or “military”.
• Spicer type bridge.

Recently, UAZ has been installing Spicer-type axles (front and rear) on the “Loaf”, and before the modernization, the vans had the most ordinary “civilian” ones. The UAZ-3303 and its modifications were never equipped with final drive axles at the factory. If you come across a “Loaf” with a “military” bridge, you should know that this is the work of the car owner.

Table

How does it work

By studying the diagram of the front axle of the UAZ “Bukhanka”, you can clearly identify the components that make up its design.

There are only three of them:

• Composite crankcase. The unit consists of two parts connected to each other by bolts. Springs and shock absorbers are installed on special mounts with which the crankcase is equipped. The rotating mechanisms located at the edges of the bridge are articulated with the edges of the crankcase casing.
• Gearbox. There are two main parts here: the main gear and the cross-axle differential.
• The axle shaft is connected to the wheel hub using a coupling, which is installed on the CV joint axle. To disable the front axle on the UAZ “Bukhanka” by switching the car’s wheel arrangement to 4 x 2 mode, you need to put the clutch in an inactive state. It will rotate freely on the axle, preventing premature wear of the gearbox parts, but the car will become less controllable and stable on the road.

The wheels are controlled using steering knuckle levers and steering rods connected to them. In general, the design of the old-style UAZ “Bukhanka” front axle is not very different from modern units, but has one fundamental difference - a drum brake mechanism.

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Drive axles UAZ-Hunter, UAZ-31519

Single-stage drive axles are installed on UAZ-Hunter and UAZ-31519 vehicles. The main gears and differentials of the front and rear axles are similar in design. The front axle is a rigid hollow beam, inside of which the main (hypoid) gear and differential are located. From the main gear of the UAZ-Hunter, UAZ-31519 axle gearbox (Fig. 1), torque is transmitted to the front hubs through axle shafts connected by wheel release clutches. The axle shafts are single parts with constant velocity joints.

Fig. 1 - Main gear (drive axle gearbox) UAZ-Hunter, UAZ-31519 1, 26, 34, 36, 37 – bolts; 2, 33 – spring washers; 3 – driven gear; 4, 24 – axle shafts; 5 – adjusting ring for differential axial displacement; 6, 22 – bearings; 7 – spacer sleeve; 8 – outer race of the outer roller bearing; 9 – roller bearing; 10 – thrust ring; 11 – oil seal; 12 – reflector; 13 – flange; 14 – washer; 15 – nut; 16 – drive axle housing; 17 – adjusting ring of the drive gear; 18 – outer race of the internal roller bearing; 19 – internal roller bearing; 20 – oil scraper ring; 21 – shaft assembly with drive gear; 23 – adjusting nut of differential bearings; 25, 39 – differential box cups; 27, 40 – support washers for the axle gears; 28, 43 – axle gears; 29, 45 – differential satellite axes; 30, 41, 44, 46 – differential satellites; 31, 38 – differential bearing covers; 32 – retainer for the differential bearing adjusting nut; 35 – main gear housing cover; 42 – main gear housing cover gasket Drain the oil through hole 2 (Fig. 3 and 4), located in the lower part of the crankcase, while also unscrewing plug 1 of the control hole. The axial clearance in the bearings of the drive gear of the UAZ-Hunter, UAZ-31519 axle reducer of more than 0.05 mm is not allowed, since if it is present, rapid wear of the gear teeth occurs and the bridge may jam. Check the presence of axial play in the bearings by rocking the drive gear by the driveshaft mounting flange. Axial play in the final drive differential bearings is also not allowed. Check it by rocking the driven gear with the crankcase cover removed or through the oil filler holes. If gaps are detected, the axle of the UAZ-Hunter, UAZ-31519 vehicle must be adjusted. The front wheels of the car are always on. The front axle and downshift are switched on and off using the transfer case lever. Rice. 2. Adjusting the angle of rotation of the wheels of the front drive axle UAZ-Hunter, UAZ-31519 1 - rotation limitation bolt; 2 - lock nut; 3 - turn stop When inspecting the steering knuckles of the drive axle UAZ-Hunter, UAZ-31519, pay attention to the serviceability of the adjusting bolts 1 (Fig. 2) and the stops of the wheel turn stops 3. The angle B of the right wheel turning to the right and the left wheel turning to the left should be within 26-27°. An increased angle of rotation of the wheels leads to contact of the wheel with the suspension parts.

Fig.3. Front axle UAZ-Hunter, UAZ-31519 with one-piece crankcase 1 - filler plug; 2 - drain plug; 3 - safety valve; 4 - lower nut, kingpin, oiler During operation, adding lubricant to the spherical kingpins and ball joints is not required (bridges shown in Fig. 3). During repairs, the lubricant in the units is replaced. Adjustment of the tightening of the pivot pins of the steering knuckle of the driving front axle of the UAZ-Hunter, UAZ-31519 is carried out with a preload along the common axis of the pins. When operating the vehicle, pay special attention to the tightness of the steering knuckle pins. When the rubbing spherical surfaces of the liners or pins wear out, the preload disappears and a gap forms along the common axis of the pins. Eliminate this gap by tightening the clamping sleeve. Operation of the front drive axle UAZ-Hunter, UAZ-31519 with gaps in the pivot assemblies leads to premature failure of the upper pivot liner. Under operating conditions, it is most convenient to tighten the clamping bushing of the lower kingpin of the UAZ-Hunter and UAZ-31519 axles:

-unscrew the nut; -remove the cover with the gasket; - use a special wrench to tighten the clamping sleeve until the gap is eliminated (after hitting the threaded end of the pin with a copper hammer); - by turning the key 10-20°, tighten this bushing to create a preload along the common axis of the pins; -install the cover with gasket; - tighten the kingpin nut with a torque of 80-100 Nm (8-10 kg/cm) (see Appendix 2). Exceeding the tightening torque will lead to a decrease in preload and failure of the pivot assembly. The turning torque of the ball joint (or the steering knuckle housing, if the ball joints were not disconnected from the axle housing) with the O-rings and the steering knuckle hinge of the drive axle UAZ-Hunter, UAZ-31519 removed in any direction relative to the common axis of the pins should be within 10- 25 Nm (1.0-2.5 kg/cm). If the control parameter is not achieved, then re-tighten the clamping sleeve by turning the wrench another 10-20° and tighten the nut to the specified torque. If it is impossible to eliminate the gaps by tightening the threaded bushing, it is necessary to replace the bushings of the pivot units of the front axle UAZ-Hunter, UAZ-31519.

Rice. 4. Front axle UAZ-Hunter, UAZ-31519 with vertical crankcase connector

1 - control plug; 2 - drain plug; 3-safety valve; 4 – grease nipple. Some models of UAZ-Hunter and UAZ-31519 vehicles can be equipped with the axles shown in Fig. 4, with pins, to which it is necessary to add lubricant during operation. To lubricate the pivot pins, grease nipples 4 are installed on the steering knuckle lever (right) and on the upper pad of the pivot pin (left). Eliminate the gap between the ends of the pivot pins and the support washers of the ball joint, which is formed when the rubbing surfaces are worn, by removing the same number of adjusting shims from above and below. The difference between the total thicknesses of the upper and lower gaskets should not exceed 0.1 mm. Dismantling the differential of the front axle UAZ-Hunter, UAZ-31519 - Remove the differential assembly with the driven gear. — Press the bearings off the differential box axle. — Remove the ten bolts securing the driven gear to the differential and remove the driven gear. — Remove the eight bolts of the differential box cups and separate the cups. — Remove the differential gears and satellites with axles. — Reassemble the differential in the reverse order of removal. Removing the main gear of the front axle gearbox UAZ-Hunter, UAZ-31519 The main gear is removed for repair or replacement. — Remove the plug and drain the oil from the rear axle. — Remove both axle shafts — Disconnect the left tie rod end from the steering arm and move the tie rod to the side. — While holding the bolts from turning, unscrew the four nuts securing the propeller shaft to the gearbox flange of the front axle UAZ-Hunter, UAZ-31519 and move it to the side. — Remove the ten bolts securing the main gear housing cover and remove the cover. — Clean the mating surface from the old gasket. — Unscrew the nut securing the front axle drive shaft flange. — Remove the flange with the reflector. — Remove the four bolts securing the differential bearing caps, remove the caps and remove the differential assembly with the driven gear, and then the shaft with the drive gear assembled with the rear bearing. — Remove the flange seal. — Remove the front pinion shaft bearing from the front axle housing. — Press out the outer races of the front and rear drive gear shaft bearings from the crankcase.

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• Clutch and gearbox UAZ Hunter
• Transfer case and driveshafts UAZ Hunter
• Drive axles UAZ Hunter
• Adjusting the steering mechanism of the UAZ Hunter

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• Checkpoint UAZ-Patriot
• Razdatka UAZ-Patriot
• Drive axles UAZ-Patriot
• UAZ-Patriot suspension
• Steering UAZ-Patriot
• UAZ Patriot power steering faults and their elimination
• Components of the UAZ-Patriot hydraulic brake drive

• UAZ-469 engine and its main parts
• Gearbox UAZ-469
• Drive front and rear axles of UAZ-469
• Clutch of UAZ-469 cars

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• Cylinder block and timing belt for UAZ-31512, 31514 engines
• Front and rear suspensions UAZ-31512, 31514
• Operations for assembly and disassembly of UAZ-31512, 31514 bridges
• Steering UAZ-31512, 31514 and its parts
• Brake system UAZ-31512, 31514

• Gearbox UAZ-452
• UAZ-452 clutch and its parts
• Transfer case UAZ-452
• UAZ-452 bridges and its components

• Gearbox UAZ-3909, UAZ-2206
• Cardan transmission UAZ-3909, UAZ-2206
• Front axle UAZ-3909, UAZ-2206
• Brakes UAZ-3909, UAZ-2206

• Clutch UAZ-3303
• Transfer case UAZ-3303
• Rear axle UAZ-3303
• Steering of UAZ-3303

• Cylinder block and crankshaft ZMZ-409
• Timing belt and valves ZMZ-409
• Lubrication system ZMZ-409
• Cooling and power system ZMZ-409

• Parts of the UMZ-421, UMZ-4218 cylinder block
• Timing belt and valves UMZ-421, UMZ-4218
• Lubrication system UMZ-421, UMZ-4218
• Cooling system UMZ-421, UMZ-4218
• Fuel system UMZ-421, UMZ-4218

How to connect

To turn on the front axle on the UAZ “Bukhanka”, follow these steps:

1. Turn the couplings connecting the wheel hub to the axle shaft.
2. Use the transfer lever, which is installed in the cab, to engage front-wheel drive.

The clutches located on each wheel are engaged/disengaged by adjusting the rotary hubcaps. Most often, there are marks on the caps that indicate the current position of the clutches - 4 x 4 / 4 x 2. On relatively new axles, you can manually switch the clutches to 4 x 4 mode by simply removing the drive axle hub cover. There is no need to crawl under the car.

After the clutches on the front wheels are switched to 4 x 4 mode, you can engage all-wheel drive: first set the transfer lever to the neutral position, and then move it to the extreme forward position.

Front-wheel drive is activated both when the car is stationary and when the car is moving (speed should be less than 40 km/h). Disabling all-wheel drive is done in the following sequence:

• stop the car;
• turn off the front axle using the transfer lever;
• Set the coupling rotary caps to the 4 x 2 position.

Important! You cannot connect the front axle only from the passenger compartment if the clutches on the wheels are disconnected.

Although driving with all-wheel drive is fun, it is very expensive: high fuel consumption, rapid wear of the front axle components and tires. Therefore, on a UAZ it is better to use the 4 x 4 mode only on problem sections of the road, and turn it off in the city or on good road surfaces.

Comparison

The main difference between “collective farm” bridges and “military” ones on UAZ vehicles is that the former do not have a gearbox in their design. On the second, the corresponding mechanism is installed. Hence the difference between the key characteristics of cars on which “collective farm” and “military” bridges are installed in the aspect:

1. speed;
2. stability on the road;
3. cross-country ability;
4. ability to climb uphill;
5. clearance values;
6. gasoline consumption.

Having determined what the difference is between “collective farm” and “military” bridges on UAZ vehicles, we will record the conclusions in a small table.

Frequent breakdowns

Although reliability and unpretentiousness to operating conditions are the main distinctive qualities of the front axle of the UAZ “Loaf”, nothing lasts forever. Quite often, UAZ owners may encounter the following types of malfunctions:

• Crankcase depressurization. It occurs due to excess pressure generated when the oil heats up while the machine is moving. Prevention: checking the functionality of the breathing valve.
• Bearing wear is the result of improper use of the front axle. Prevention: engage all-wheel drive only when off-road.
• Using poor quality lubricant can cause rapid wear of rotating parts. Prevention: timely oil change and preventing water from entering the crankcase.
• Wear of the pins is a common cause of malfunction of the cross-axle differential.
• Regularly monitoring tire pressure will help prevent premature wear of the bevel pinion axles and the parts themselves.

Almost any car owner, having little skill in auto mechanics, can repair and adjust the front axle of a UAZ “Bukhanka” with his own hands. Have you, dear UAZ owners, tried to repair the axle of your car yourself?