What is a portal bridge
The idea itself of placing the beam above the wheel axle has been incubated since 1946. German engineer Albert Friedrich used a similar scheme on Unimog SUVs. There is only one way to increase the ground clearance of a car with continuous axles - installing portal axles. On UAZ, such a scheme began to be used only in the late 60s, when the Soviet designer Mirzoev, the author of gear axles on the UAZ 469, received a record ground clearance at that time - 378 mm.
At that time, the maximum ground clearance was considered to be 250 mm. Portal axles could not be used on every European SUV; it was possible to install only on a number of models:
- Unimog;
- UAZ;
- Volvo C303;
- Pinzgauer.
From the diagram presented above, it is clear that the portal bridge is a continuous beam and final wheel drives. Due to the gearboxes, the axle can be raised to a certain height relative to the wheel axis, plus, the dimensions of the main gear are significantly reduced, which makes it possible to reduce the dimensions of the main gearbox housing.
Portal bridges: Features and purpose
Several car models have such a distinctive feature as portal axles. They make it possible to increase the ground clearance of vehicles to 380 millimeters, a record figure. However, not everyone knows what the features of such a design are and why it is needed.
Design and advantages. Portal bridges mainly get their name from their distinctive “U” shape. They are distinguished by the presence of final drives, due to which the vehicle's ground clearance increases and the axle rises in relation to the wheels. Another characteristic feature of this design is the reduced size of the main gear and its housing.
Typically, portal axles are used by fans of off-road racing and the military, since instead of one gearbox, three are used at once, which in turn increases the cross-country ability of the car, and it also becomes possible to install larger wheels.
Such solutions have several advantages, which include:
- Increased towing capacity - the car can carry large loads, without losing speed, drive through mud, snow, and off-road
- Increased ground clearance
- Reliability
Military bridges. Military axles are distinguished by the presence of final drives, so they are more elevated in relation to the wheels than a conventional design. In appearance, the bridge resembles the letter “P”, and the ground clearance is raised to the maximum. The torque is distributed between the main pair and the gearbox. The main pair has fewer teeth, but they are larger than usual.
"Laplander" bridges. These designs are most common among off-road racing enthusiasts, as they are even more reliable than military ones. The design is distinguished by the highest ground clearance, they are lighter and can be repaired without problems. Mostly “Laplander” bridges are produced by Swedish manufacturers. Their special feature is the presence of self-locking limited-slip differentials and the option of completely locking them using a vacuum servo drive.
It is worth noting that portal axles make the car heavier, and therefore reduce its top speed. But at the same time, the high-torque and cross-country ability of the vehicle, as well as its reliability, increase.
Bottom line. Not long ago, enthusiasts, off-road racing enthusiasts and military personnel began using portal axles to design their vehicles. They provide several advantages due to their interesting design, but at the same time they increase the weight of the car and reduce their top speed.
- Exactly those feelings. Experience with Bridgestone Turanza T005 tires.
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Advantages of portals for SUVs
The very name of portal bridges comes from the definition - in mechanical engineering a portal is called a spatial load-bearing structure. Such bridges are used only in military equipment and on fierce SUVs, where, more than anywhere else, an increase in ground clearance comes in handy. Also, such axles help reduce the load on the clutch, reduction gearbox, transfer case and gearbox if wheels of a larger diameter are installed compared to stock ones.
As a result, we get a whole list of advantages valuable for off-road vehicles:
- the ability to obtain increased ground clearance, which can easily be varied by installing wheels of different diameters;
- the lower gear ratio of the portal axles on the UAZ 469, on the UAZ Hunter allows for greater traction force, which is also important when driving in conditions of impassable mud and loose snow;
- the smaller the number of teeth in the main gear, the more reliable the gearbox, and on portal bridges the teeth of the main pair are also larger, which means increased reliability of such gearboxes.
There are also some disadvantages. For example, the maximum speed will be reduced by 20 percent, depending on the gear ratio of the main pair. But this minus is not at all fatal for cars designed to operate in total off-road conditions. The installation of portal axles has virtually no effect on handling; according to engineering calculations, it worsens by no more than 3%, but the dynamics of acceleration drops by 35-40% compared to a standard drive axle.
Adjustment with replacement of bearings
- Unscrew the axle shafts, remove the crankcase cover or gearbox (depending on the type of axle)
- Remove the cover from the bearings.
- Using a dynamometer, measure the friction torque of the gear.
- Remove the rings from the differential box and install new ones.
- Install new bearings.
- Replace and secure all previously removed covers. It is advisable to apply force for a more reliable fixation. The bolts must be lubricated with a special sealant.
- In order to increase the moment of resistance to rotation, it is necessary to tighten the adjusting nuts one by one until the optimal value of resistance to rotation is achieved equal to 200-250 N.
- Install all previously removed parts, including the axle shafts.
- Tighten all fasteners securely.
Portal bridges for UAZ
In nature, there are several models of portal bridges, including domestic ones. Let's start with them, perhaps. The most budget-friendly way to install a portal axle on an SUV is to install and fit a used axle yourself. Depending on the car model, you can use a military portal bridge from UAZ. The downside is obvious - there is a lot of work to be done, and the condition of the three gearboxes that are installed in the beam is unknown. You can check the performance and find out the degree of wear only by opening the gearbox.
For sale there are both new axles from UAZ 3151-03 and used ones. They are slower than standard bridges from civilian UAZs, but also have higher torque. How much the game is worth the candle is up to everyone to decide individually, since the increase in ground clearance is 80 mm - 40 mm is obtained by reducing the size of the gearbox housing and another 40 by shifting the beam axis relative to the wheel axis.
Preventive maintenance and timely detection of defects
From time to time it is necessary to pay attention to the running parts of the car. This will have a positive effect on operation and reduce the likelihood of car breakdowns.
When carrying out prevention it is necessary:
- Check the oil level in the crankcase, add or change if necessary. The oil is drained through a special hole at the bottom of the crankcase. But in order to drain the oil completely, you need to open the filler hole by unscrewing the top plug. If necessary, the container must be rinsed.
- Adjust axial clearances. The presence of a gap between the gearbox transmission and the drive gear bearing will lead to rapid wear of the teeth. This can be determined by shaking the driveshaft mount. To fix it, you need to tighten the nut using a certain force.
- Clean all visible parts of the bridge, including the safety valve. Clean all dirt deposits with a coarse brush.
- Check the steering knuckles. You should pay attention to the levers of the fists, or more precisely, to its fastening. Wheel turn stops must always be intact.
- Check all fastenings. If necessary, tighten the bolts and nuts using wrenches of the required diameter.
The front axle of the UAZ “loaf” has a similar device. He also needs to carry out similar preventive measures.
Features of portal bridge 3151-03
Such an axle is much more reliable than the standard one, since they have larger main gear teeth and the torque is distributed more evenly between three gearboxes, and does not fall on one, as in the Standard UAZ. What's bad is that a military bridge is heavier, has more parts and is much more difficult to repair. You also need to take into account that fuel consumption will be slightly higher. For example, a UAZ Patriot with portal axles will ask for two liters of gasoline more than a regular Patriot with civilian axles. There is a modification of such a bridge, 3159 Bars, in which the track has become wider and is 1600 mm with the same ground clearance of 80 mm. The hubs on both axles require the installation of 15-inch discs.
Branded final drives will not be affordable for everyone, since without installation a hardware kit for, say, Tibus will cost a million rubles.
Therefore, the only option for installing portals on a UAZ is to purchase used or new military bridges from model 3151-03. The price of such bridges ranges from 60-70 thousand assembled. Happy travels to everyone!
How much does UAZ “Bukhanka” weigh for scrap metal?
Most often, the body of a Bukhanka car is handed in for recycling, since the remaining spare parts are mostly sold as used parts. The body weight of the “Loaf” is approximately 760 kg. However, if the “Loaf” assembly (body, bridge, engine and others) is subject to disposal, then the weight can reach 2 tons. In this case, it is necessary to take into account a number of factors taken into account by buyers when accepting this kind of scrap for recycling, answering the question of how much the UAZ “Loaf” weighs for scrap metal:
- the weight of the purchased material does not include non-metallic parts;
- when weighing, the degree of clogging of parts is also taken into account;
- When accepting the “Loaf” for disposal, 30 percent of the total weight will be taken away for blockage.
Thus, it should be noted that if the total weight of the “Loaf” is approximately 1700 kg, then you can get real money only for 1190 kg. However, you can try to increase your income by dismantling the car for parts and selling the body and other elements of the “Loaf” separately.
From all of the above, it follows that by deciding to recycle the body of a UAZ “Bukhanka” car, you can get money for scrap weighing 768 kg, with a net weight of the entire vehicle of 1190. Therefore, it is most advisable to sell a disassembled car as scrap for recycling, and earn an order of magnitude more. In any case, proper disposal of vehicles will allow you to generate revenue by getting rid of unnecessary scrap without littering the area.
UAZ 452 “Loaf” is a modified model of the UAZ-451, the disadvantages of which were poor off-road performance.
There are several varieties of it:
Characteristics of this model in terms of load capacity:
- vehicle weight without load – from 1845 kg to 2080 kg;
- the platform is designed for loads not exceeding 700 kg in weight;
- the cargo compartment allows you to transport 400 kg - 1 ton of cargo;
- towing a trailer with a gross weight with brakes - 1.5 tons, without brakes - 750 kg;
- maximum permitted load from 2.5 to 3 tons;
- number of passenger seats – up to 10.
UAZ Bukhanka: technical characteristics and performance characteristics vary depending on the selected modification (409, 452, 452 A, 452 D). This vehicle has been produced by the Ulyanovsk plant since 1965.
