Possible malfunctions and methods for eliminating them on Ural 4320 vehicles

The URAL truck is a very reliable vehicle and rarely fails. But even she sometimes has breakdowns. There is a very unpleasant situation when the URAL engine stalls and does not want to start. At the same time, a message with a corresponding description of the fault code appears on the instrument panel display. But there are exceptions when errors are not displayed. Our company’s specialists have accumulated solid experience in diagnosing and repairing the described faults. There are two radically different options for not starting the engine:

When you turn the key in the ignition, the starter cranks the excavator engine
The starter does not turn on and does not turn the engine

I will try to tell you in more detail about each of the options for equipment malfunction.

Preheater

► Malfunction: Overheating of the heater boiler, water escaping through the filler neck of the heater
Probable cause: Formation of ice plugs in the supply pipes due to non-compliance with the instructions for completely draining the water or improper use of the heater. No circulation

Remedy: Warm the pipes by periodically turning the heater on and off at intervals of 2-3 minutes, pouring hot water over the outside of the pipes

► Malfunction: The heater does not start

Probable cause:

The electric motor of the pump unit does not rotate:

freezing of the fan impeller due to incomplete removal of water from it after washing the car or fording

Remedy: Warm the fan and liquid pump housing using improvised means

Probable cause:

The electric motor of the pump unit does not rotate:

freezing of the liquid pump impeller due to non-compliance with the instructions for draining water from the cooling system.

Remedy: Warm the fan and liquid pump housing using improvised means

Probable cause: Open circuit in the high voltage source

Remedy: Check and tighten the terminal connections of the current supply wires

Probable Cause: High voltage source is not working

Remedy: Disconnect the high voltage wire and secure its end at a distance of 3-5 mm from the ground of the car, if there is no spark when turning on the spark plug, replace the high voltage source

Probable cause: Spark plug not working

Remedy: Clean or replace spark plug

Probable cause: The solenoid valve does not operate (there is no click when the solenoid valve is turned on). The fuel filter in the solenoid valve or injector is clogged. Injector is clogged.

Remedy: Disassemble the nozzle, wash the parts in kerosene or acetone. Assemble the nozzle and check the quality of atomization without screwing the nozzles into the burner

► Malfunction: The heater smokes or throws out flames

Probable cause: Fuel pump adjustment is out of order

Remedy: Reduce fuel consumption by adjusting the fuel pump pressure reducing valve

Probable cause: Low speed of the electric motor shaft

Remedy: Charge the battery, check the serviceability of the electric motor

► Malfunction: Prolonged warm-up of the engine, unstable combustion of the heater

Probable cause: Low fuel supply due to clogged injector filter, leaking fuel lines, improper fuel pump adjustment

Method of elimination: Wash the filters, injector, and eliminate leaks in the fuel lines. Adjust the fuel pump pressure reducing valve

Brakes do not light up Ural 4320

The main task of diagnosing a machine can be called identifying breakdowns of the Ural-4320 brake system and correcting them in a timely manner.
Let's consider the sequence of monitoring the state indicator of the braking system of the Ural-4320 vehicle:

Loosen the nuts securing the wiring to the brake status indicator switch slightly;
Unscrew the indicator switch from the pneumatic amplifier;
Tighten the nuts securing the wires;
Turn on the devices;
Connect the switch housing to vehicle ground and press the button as far as possible.

If the control indicator lights up, then the status indicator is working properly. You need to do the same with the other status indicator switch. If the indicator does not light up, it should be replaced.

In addition, it is necessary to check the operation of the pneumatic drive on the Ural-4320 machine. You should proceed as follows:

Control pressure gauges must be connected to the control output valves;
Fill the pneumatic system with air until the pressure regulator operates.

It is worth remembering that in operating brake drive circuits, pressure fluctuations are permissible in the range from 650 to 800 kilopascals. The pressure on the control and two-pointer pressure gauges should be similar. By systematically monitoring the main components of the braking system, you can prevent frequent breakdowns and malfunctions. If you were unable to avoid this, you should carry out diagnostics, buy Ural spare parts and repair the breakdown.

We propose to consider the main breakdowns of the braking system:

Air tanks fill very slowly. More often, the cause of such a malfunction can be damage to the cylinder and the appearance of cracks.
The air cylinders of the third and fourth circuits are not completely filled. This may be caused by a faulty double safety valve or a clogged pipeline.
The air cylinders of the first and second circuits are not completely filled. This may be caused by a clogged triple valve and piping, or a lack of clearance in the triple safety valve.
The cylinders on the trailer are not completely filled. More often, such a breakdown occurs due to a breakdown of the trailer brake control units.
Excessive or insufficient pressure in the air cylinders of the primary and secondary circuits. Here it is necessary to adjust the operation of the pressure regulator and check the operation of the two-pointer pressure gauge.
The brake pedal is faulty. This may be caused by poor adjustment of the brake valve, a malfunction of the pressure limiting valve, or a breakdown of the brake valve, an incorrectly mounted brake valve regulator drive, as well as excessive stroke of the brake chamber rods.
Parking and emergency brakes are faulty. The breakdown may be caused by a malfunction of the accelerator valve, emergency brake release valve, excessive stroke of the chamber rods, or an incorrectly mounted brake valve regulator drive.
The vehicle will not release the parking or emergency brake. Such a breakdown can be caused by an air leak from the third circuit, a faulty bearing of the thrust energy accumulator, or a breakdown of the output of the atmospheric acceleration valve.
When using the additional braking system, braking is not possible. This may be caused by a malfunction of the pneumatic valve that triggers the additional brake, or a breakdown of the solenoid valve or dampers.
Oil penetrates into pneumatic systems. In this case, it is necessary to check the piston rings, as well as the compressor cylinders.

Source

Transfer case

► Fault: Increased noise

Probable cause: Insufficient oil in transfer case

Remedy: Fill the oil to the level of the control plug

Probable Cause: Increased axial movement of the input and intermediate shafts

Remedy: Adjust bearings or replace with new ones

► Malfunction: Self-switching off gears

Probable cause: Worn gear shift fork and clutch. Worn gear shift splines and input shaft

Remedy: Replace worn parts

Probable Cause: Increased axial movement of input shaft

Remedy: Adjust bearings or replace with new ones

► Malfunction: Difficulty engaging gears and differential locking

Probable cause: Burrs on gear splines, front race, engagement clutches

Remedy: Clean the surface of the splines

Probable Cause: Latch Sticking

Remedy: Clean the ball hole

Drive axles

► Fault: Increased bridge noise

Probable cause: Displacement of the contact patch of the bevel gears to the edge of the narrow end of the tooth

Remedy: Adjust the engagement according to the contact patch

Probable cause: Gear bearing clearance

Remedy: Restore bearing preload

Probable cause: Wear, damage to the working surface of the gear teeth

Remedy: Replace gears

Wheels and tires

► Malfunction: Intense uneven wear of the tread pattern

Remedy: Incorrect alignment of steered wheels

Probable Cause: Adjust wheel alignment

Elimination method: The adjustment of the wheel hub bearings and steering knuckle bearings is incorrect

Probable Cause: Adjust bearings

Remedy: Worn steering rod joint parts

Probable cause: Replace worn parts with new ones.

Remedy: Large radial or lateral wheel runout

Probable cause: Replace wheels with increased radial or lateral runout

Method of elimination: Sharp braking or starting, driving with low or very high internal tire pressure, overloading the tires with the weight of the load.

Probable Cause: Follow the rules and use sound driving techniques.

Remedy: Strictly observe tire inflation pressure standards and do not overload tires.

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Troubleshooting Ural-4320

Ural-4320 This is a very reliable machine, and the electrical equipment is made with high quality and professionalism.

Malfunction: Turn signals do not work.

First of all, we check the fuse, which is not located on the fuse panel, but is cleverly hidden in a bundle of wires not far from the emergency light button, we check it.

If the fuse is intact, then we disconnect the turn relay, usually PC951 and its modifications, and check the turn circuits.

Checking the circuit is as follows: you just need to apply positive power to the right side of the turns and if there is no short circuit in it, then it will light up and check the left side in the same way.

If a short circuit is detected in any of the circuits, then it needs to be found and eliminated. Possible places for the short circuit are: turn signals (or rather, the wires going to them often fray and short out on the fender), an incorrectly inserted light bulb shorting to ground in the turn signal itself , a wire fell out in the connecting block under the hood, well, the dirtiest thing, but as a rule, it breaks and shorts there very often, this is in the bundle that goes along the frame to the rear corners.

Steering

► Malfunction: Unstable vehicle movement, steering wheel free play more than 25°

Probable cause: Wear of the worm-sector pair. Wear of the rack-sector pair

Remedy: Adjust the amount of side clearance between the teeth of the worm and the sector, the rack and the sector

Probable cause: Wear of steering rod joint parts, splined bushings of the steering cardan drive

Remedy: Replace worn parts with new ones, lubricate spline joints

Probable Cause: Loose steering gear

Remedy: Tighten the crankcase mounting bolts

► Fault: “Heavy” steering

Probable cause: Insufficient oil level in the steering hydraulic system reservoir

Remedy: Add oil to the required level

Probable cause: Presence of air or water in the system (foam in the tank, cloudy oil)

Remedy: Remove the air. If air is not removed, check the tightness of all connections, remove and wash the strainer, and check the integrity of the gasket under the manifold. Check the tightness of the manifold mounting bolts and, if all of the above does not resolve the problem, change the oil

Probable Cause: Insufficient pump drive belt tension

Remedy: Tension the belt

Probable cause: Pump does not provide required flow and pressure

Remedy: Check the pump

Probable cause: Increased oil leakage in the switchgear, scuffing on the spool bearing surfaces

Remedy: Replace the switchgear

Probable cause: Loose spool nut

Remedy: Unlock the nut, tighten it and lock it again by pressing the collar into the groove of the shaft

Probable cause: Loss of mobility of the steering driveshaft spline

Remedy: Disassemble, clean and lubricate

Probable cause: Pump safety valve seat loosened

Remedy: Disassemble the pump, tighten the seat

Electrical diagram of URAL-6370

1. Car tachograph
2. Engine Interface Unit (ECU)
3. Warning lamp block
4. Cruise control switch
4. Cruise control switch
5. Starter and instrument switch
6. Steering column switch for turns and headlights
7. Steering column wiper and washer switch
8. Electronic speedometer
9. On-board voltage indicator
10. Electronic tachometer
11. Coolant temperature gauge
12. Oil pressure indicator in the engine lubrication system
13. Fuel level indicator
14. Two-pointer pressure gauge
15. Auxiliary brake switch
16. Center differential lock switch
17. Unloading area headlight switch
18. Rear fog light switch
19. Cross-axle differential lock switch
20. Outdoor lighting switch
21. Turn signal breaker relay
22. Remote ground switch
23. Hazard switch
24. Rear fog lights R13
25. Cabin lift switch
26. Pump motor
27. Radiator grille open sensor
28. Thermobimetallic fuse
29. Cabin lift relay
30. Cabin heater valve.
31. Cabin heater motor
32. Electrically controlled left rear view mirror
33. Left turn signal repeater
34.56. Cabin lights
35. Cabin lantern illuminating the loading area
36.57. Door lamp switches
37. Front left contour lamp
38. Left side marker light
39,40,41. Road train sign lights
42. Road train sign switch
43. Rear view mirror control unit
44. Pads for connection with independent heater and heater
45. Illumination of cabin heater control.
46. Cab heater tap control switch.
47. Cab heater motor control switch
48. Right side marker light
49. Front right contour lamp
50. Electrically controlled rear view mirror, right
51. EDC diagnostic switch
52. ODI diagnostic switch
53. Portable lamp socket
54. Diagnostic connector
55. Right turn signal repeater
58. Platform lift switch
59. Dump trailer control switch
60. Heated mirror switch
61. Accelerator pedal
62. Fuse block F1
63. Fuse block F2
64. Fuse block F3
65. Starter relay R1
66. Relay for unloading terminal “15” R2
67. Relay for unloading terminal “15” R3
68. Wiper relay R4
69. Additional relay for rear fog lights
70. Side light relay R6
71. Fuse block F4
72. Low beam headlight relay R7
73. High beam headlight relay R8
74. Horn relay R9
75. Stop signal relay R10
76. Fuse block F5
77. Fuse block F6
78. Heated mirror relay for URAL cars
79. Headlight range control unit
80. Relay brake pedal position sensor
81. Center differential switch RK
82. Power take-off switch
83. Additional power take-off switch
84. Transfer case gear button
85. Transfer case gear selector
86. Center differential solenoid valve
87. Low gear solenoid valve RK
88. Neutral solenoid valve RK
89. High gear solenoid valve
90. Solenoid valve for power take-off
91. Additional power take-off solenoid valve
92. Windshield washer motor
93. Wiper motor
94.107. Additional high beam headlights
95.106. Fog lights
96. Left turn signal
97. Left low beam headlight module
98. Left headlight corrector motor
99. High beam headlight module with left side marker
100,101. Beep signal
102. High beam headlight module with right side marker
103. Right headlight corrector motor
104. Right low-beam headlight module
105. Right direction indicator
108,109,116,117. Side marker lights
110. Rear right lamp
111,112. Unloading area lights
113. Left rear lamp
114,115. Trailer sockets
118. Engine brake flap valve
119. Camshaft speed sensor
120. Pressure sensor URAL 6370
121. Low pressure and low temperature sensor top
122. Oil pressure and temperature sensor
123. Boost pressure and temperature sensor
124. Camshaft speed sensor
125. Fan control valve
126. Fan speed sensor
127. Ambient temperature sensor
128. Fuel measuring device
129,150,131,132,133,134. Fuel injection nozzles
135. Electronic control unit
136. Heating elements for air preheating
137. Air preheating relay
138,139. Heating elements for heating fuel fine filter
140. Fuel heating thermostat
141. Air dryer heating element
142. Water in fuel level sensor
143. Heating element for heating fuel in the coarse filter
144. Starter
145. Generator
146. Fuel level sensor
147,148. Rechargeable batteries
149. Ground switch
150,151. Wheel lock sensors
152. Sensor for turning on the center lock
153. Downshift sensor RK
154. Power take-off switch
155. Center lock sensor
156. Air filter clogging sensor
157,158. Pneumatic brake signal switches
159. Electro-pneumatic valve for lifting a dump trailer
160,161. Electro-pneumatic valve for platform lift
162,163,164. Emergency air pressure sensors
165. Parking brake sensor
166. Speed sensor
167. Neutral sensor
168. Clutch sensor
169. Reverse signal sensor
170. Electro-pneumatic valve for interaxle locking
171. Electro-pneumatic valve for inter-wheel locking

Brake system

► Malfunction: When you press the brake pedal, the car does not slow down - the brake warning light comes on

Probable cause: Worn friction linings, large gaps between the pads and drums of the service brakes

Remedy: Replace the friction linings. Adjust the gaps between the brake pads and drums

Probable cause: Lack of brake fluid in the master cylinder reservoirs

Remedy: Replace the brake fluid, bleed the brakes if necessary

► Malfunction: The minimum air pressure warning light is constantly on (with the engine running)

Probable cause: Lack of air in the cylinders due to a malfunction of the compressor, pressure regulator, or leaking pneumatic system

Elimination method: Eliminate the compressor malfunction, replace the pressure regulator. Locate the air leak and repair the damage

► Malfunction: Braking is not effective enough - the brake warning light comes on

Probable Cause: Brake fluid leak or air in the master cylinder or hydraulic line of one of the brake circuits

Remedy method: Determine the location of the fluid leak and repair the damage. Fill with brake fluid and bleed the brakes

► Malfunction: Braking is not effective enough - the minimum air pressure indicator light comes on

Probable Cause: Worn inner seal or lack of fluid in one of the master cylinders

Remedy: Replace the cuff. Add fluid, bleed the brakes

Probable cause: Worn piston cuffs or pneumatic booster spacer cuffs; in this case, when the pedal is pressed, air comes out of the air booster filter

Remedy: Replace the cuffs

► Malfunction: The brake jams (does not release)

Probable cause: Lack of brake pedal free play

Remedy: Adjust the brake pedal free play

Probable cause: Mineral oil entering the hydraulic drive, causing swelling of the rubber cuffs

Remedy: Wash the hydraulic drive with alcohol, replace the cuffs

Probable cause: Clogged compensation hole in the master cylinder

Remedy: Remove the tank and clean the compensation hole with a soft wire with a diameter of 0.6 mm

► Malfunction: Frequent operation of the pressure regulator

Probable cause: Compressed air leak in the line from the regulator to the valve block

Remedy: Tighten connections, replace faulty connection parts, pipelines

Relays and fuses

URAL relays and fuses are located in the cab on the mounting block to the right of the instrument panel under a removable cover. The serial number of fuses in the list corresponds to their numbering on the blocks.

1-relay for unloading terminal “15” (P2); 2-starter relay (P1); 3, 4, 6, 8, 9, 11 - fuse blocks; 5-relay for unloading terminal “15” (R3); 7-windshield wiper relay (R4); 10-rear fog lights relay; 12-diagnostic connector; 13-relay pneumatic brake signal switch (R12); 14-mirror heating relay (R11); 15-stop signal relay (R10); 16-horn relay (R9); 17-high beam relay (R8); 18-low beam relay (R7); 19-side light relay (R6); 20-relay additional rear fog lights (R5).

CAR ELECTRONICS REPAIR