Diagnostics of faults in the driveshaft, rear axle, chassis, steering and braking system
(This section also mentions faults in other systems with similar symptoms. They are marked with the * symbol)
Cause of malfunction | Method of elimination |
Knocking when starting off | |
| Wear of the splined connection of the front end of the cardan shaft with its flange or cardan joints (clacking), loosening of the fastening of the intermediate support to the bracket or the bracket to the body (dull sound) | Lubricate the splined joints with SHRUS-4, Fiol-1 or Litol-24 grease. Replace worn cardan joints or the cardan shaft assembly, tighten the intermediate support fasteners |
| There is a large gap in the engagement of the main transmission gears, their teeth are worn out | Adjust the lateral clearance in the gear engagement. Replace worn gears |
| The clearance in the engagement of the main gear gears is violated due to the loosening of the tailstock nut | Tighten the nut to the recommended torque, install a new spacer sleeve if necessary |
| Broken rear suspension reaction rods or their mounting brackets, play in silent blocks | Replace the rods, weld the brackets |
| Wheel bolts have come loose | Tighten the bolts to the recommended torque |
| Brake pads stuck or frozen to drum | This is not a malfunction. |
| Brake lining separation from the base of the shoe | Replace the pad (better to have everything on one axis at the same time) |
| * Clutch faulty | |
| * The power unit mounts have lost their elasticity or have been destroyed | Replace the supports |
Noise when driving a car on a smooth highway | |
| The rear axle gearbox bearings are worn out, their preload is broken, and the fit is loose (uniform noise from the rear axle) | Replace worn bearings, spacer sleeve, adjust preload (see Rear axle) |
| The teeth of the main gear are worn, the lateral clearance in the engagement is disturbed, there are scuffs on the teeth: a howl from the rear axle, decreasing or disappearing when the load is reduced (the gas pedal is released) | Replace worn gears, adjust backlash |
| The drive gear has become loose in the differential box (gear runout) | Tighten the threaded connections (you can use thread sealant), replace worn gears (in pairs) |
| Worn axle bearings or front wheel hub bearings | Replace the bearings |
| The intermediate support bearing is worn out | Replace the bearing |
| Cardan shaft imbalance | Check if the bearing retaining rings are in place. Have the cardan transmission balanced at a service station or replaced |
| The tires are not designed for these operating conditions (on asphalt, all-terrain tires, studded tires, anti-skid chains, etc. are used.) | Use tires according to their intended purpose |
| High speed in corners | Reduce speed before turning. Adjust front wheel alignment, tire pressure |
| Uneven wear or tread separation, deformation of the tire, rim | Replace the wheel |
| The wheel is touching the fender liner (especially on a loaded vehicle) | Check and adjust the wheel alignment angles, replace deformed suspension parts, sagging springs. Do not overload the car. Use only standard wheels |
| Wheel bolts are hitting rear brake components | Use bolts according to the thickness of the wheel rim |
| Brake components are rubbing against the brake disc/drum | Disassemble the unit, replace defective parts |
| The wheel mounting bolts have come loose | Tighten the bolts; if the wheel is deformed, replace the wheel |
| Brake lining separation from the base of the shoe | Replace the pad (better to have everything on one axis at the same time) |
| * Engine, clutch, gearbox faults | See the relevant sections of "Diagnostics" |
| * Howling, whistling from the luggage rack (cargo) on the roof | Reduce speed |
Knocking, creaking when driving off-road | |
| The car is overloaded | Do not overload the car. Distribute the load evenly, using the interior |
| The shock absorbers are faulty, their fastenings have become loose, the rubber cushions have worn out | Replace the shock absorber (better both at the same time on one axis), rubber cushions |
| Suspension buffer failure (front or back) or additional upper buffer (rear) | Replace buffer/buffers |
| Settling or breakage of the suspension spring | Replace the spring (it is better to replace both springs at once – left and right) |
| Broken rear suspension reaction rods or their mounting brackets, play in silent blocks | Replace the rods, weld the brackets |
| The exhaust system is incorrectly mounted or deformed: its parts touch the road or the driveshaft | Replace the exhaust system or change the position of its parts (taking into account the suspension travel) |
| Worn or not lubricated front suspension ball joints | Measure the wear of the ball joints (see Front suspension), make sure the ball joints move freely. Put fresh SHRB-4 grease in the covers (the lower support can be injected) |
| Worn or damaged front suspension silent blocks | Replace the silent blocks |
| The lower and/or upper arm axle mount has become loose | Tighten the threaded connections |
| The front suspension beam has become loose from the body side members | Tighten the threaded connections |
| The steering wheel mount on the shaft, the steering column to the bracket, the steering gear and the pendulum arm bracket to the body side members have become loose | Tighten the threaded connections |
| Knocking in the steering mechanism: severe wear or destruction of the working surfaces of the worm and roller, pendulum arm bushings, the clearance in the engagement is not adjusted, there is no oil in the steering mechanism housing | Replace worn parts, adjust the gap in the engagement of the roller and worm, add oil |
| Bent suspension elements (levers, stabilizer bar), steering rods. Suspension parts have become loose | Straighten or replace deformed parts. Tighten threaded connections |
| The exhaust system mounting straps are loose or missing, the clamp that secures the exhaust pipe to the bracket on the gearbox | Install new belts, clamp |
| * The power unit mounts have lost their elasticity or have been destroyed | Replace the supports |
| The half shaft and brake shield mount to the rear axle beam has become loose | Tighten the threaded connections |
| High tire pressure | Set the pressure to normal |
Noise or clicking in the rear axle when turning the car or when one of the drive wheels slips | |
| The teeth of the satellites or axle gears are worn or broken | Adjust the axial clearance of the axle gears, replace heavily worn or broken parts |
Knocking, creaking when turning the car | |
| The wheel mounting bolts have come loose | Tighten the bolts, if the wheel is deformed, replace the wheel |
| Increased axial play of the wheel (severe wear of front wheel bearings or loose hub nut) | Tighten the wheel hub nut, replace the bearing if necessary |
| The wheel is touching the fender liner (especially on a loaded vehicle) | Replace deformed suspension parts, sagging springs. Do not overload the car. Use only standard wheels |
| Suspension spring failure | Replace the spring (it is better to replace both suspension springs at once – left and right) |
| Broken rear suspension reaction rods or their mounting brackets, play in silent blocks | Replace the rods, weld the brackets |
| Worn or not lubricated front suspension ball joints | Measure the wear of the ball joints (see Front suspension), make sure the ball joints move freely. Put fresh SHRB-4 grease in the covers (the lower support can be injected) |
| Worn or damaged front suspension silent blocks | Replace the silent blocks |
| The lower and/or upper arm axle mount has become loose | Tighten the threaded connections |
| The front suspension beam has become loose from the body side members | Tighten the threaded connections |
| The steering column has become loose in connection with the bracket, the steering gear and the pendulum arm bracket have become loose in connection with the body side members | Tighten the threaded connections |
| Knocking in the steering mechanism: severe wear or destruction of the working surfaces of the worm and roller, the bushings of the steering arm shaft, the clearance in the engagement is not adjusted, there is no oil in the steering mechanism housing | Replace worn parts, adjust the gap in the engagement of the roller and worm, add oil |
| Bent suspension elements (levers, stabilizer bar), steering rods | Straighten or replace deformed parts |
Vibration when the car is moving | |
| Increased imbalance of the front wheels, tire deformation or uneven wear, wheel deformation (the steering wheel beats) | Balance the wheels, deformed or unevenly worn tires, deformed wheels - replace |
| Severe imbalance of the rear wheels, tire deformation or uneven wear, wheel deformation (vibration of the rear of the car) | Balance the wheels, deformed or unevenly worn tires, deformed wheels - replace |
| Deformation of the cardan shaft/shafts, loss of balancing weights (plates) | Repair the cardan transmission at a service station with subsequent dynamic balancing or replace it |
| Large play in the crosspiece in the cardan joint, the retaining ring falling out of the joint fork | Check for the presence of retaining rings in the fork grooves, axial movement of the crosspiece. Adjust the play, replace worn parts |
| The fastening of the cardan transmission parts has become loose | Tighten the threaded connections |
| The intermediate support has become loose on the bracket or the bracket on the body | Tighten the fasteners |
| The tires are not designed for these operating conditions (on the highway, all-terrain tires, studded tires, anti-skid chains, etc. are used.) | Use tires according to their intended purpose |
| Uneven wear or tread separation, deformation of the tire, rim | Replace the wheel |
Car rocking on the road | |
| The shock absorber is faulty | Replace the shock absorber (better both at the same time on one axis) |
Vibration when braking | |
| Brake disc deformation | Replace the disk (better in pairs) |
| Increased axial play of the wheel (severe wear of front wheel bearings or loose hub nut) | Tighten the wheel hub nut, replace the bearing if necessary |
| Brake drum ovality | Grind or replace the drum |
| The piston in the rear wheel cylinder is jammed | Replace the cylinder |
| The brake shoe lining has separated from the base | Replace the pad (better to have everything on one axis at the same time) |
| The rear brake shoe tension spring is weak or broken | Replace the spring |
Squeaking, squealing when braking | |
| Maximum wear of brake linings | Replace the brake pads (better to have everything on one axis at the same time) |
| Introduction of foreign particles (sand) into the lining material | As a rule, it does not require intervention (you can clean the linings with a wire brush) |
| Low quality of the overlay material | Replace the pad (better to have everything on one axis at the same time) |
| Severe corrosion of the brake disc (due to poor quality of the disc material and/or lining) | Grind (sharpen) or replace the disc |
| The brake shoe lining has separated from the base | Replace the pad (better to have everything on one axis at the same time) |
| The rear brake shoe tension spring is weak or broken | Replace the spring |
| Braking with wheel lock | Do not over-brake, use tires appropriate to the driving conditions |
Increased brake pedal travel (pedal is "soft" or "falls through") | |
| Air in the brake system, brake fluid leakage through leaks in hydraulic drive connections, damage to the cuffs in the main brake cylinder, pressure regulator, damage to brake pipes and hoses | Inspect all lines, their threaded connections and cylinders, eliminate leaks. Restore the normal fluid level in the brake reservoir and bleed the system. If damage to the brake hoses is detected (cracks, bulges or traces of brake fluid) – replace the hoses. If you suspect defects in the master brake cylinder, replace it with a known good one |
| The rubber seals of the cylinders swelled due to oil, gasoline, etc. getting into the brake fluid. | Replace cylinders, hoses, completely drain brake fluid, flush the system with fresh fluid and bleed |
| Overheating of brake mechanisms | Allow the brakes to cool. Check the thickness of the linings and brake discs. Use only brake fluids recommended by the manufacturer in the system. Replace the brake fluid in time |
| Increased clearance between the pads and the drum (the automatic gap adjustment device does not work) | Replace the wheel cylinder, bleed the system |
| Increased (more than 0.25 mm along the edge) brake disc runout | Replace the disk |
| One of the circuits of the service brake system is not working | Fix the brake fluid leak, bleed the system |
The brake pedal travel is within normal limits (the pedal is "hard"), but the car brakes poorly | |
| Oiling of brake discs, drums, linings | Clean oily discs and drums, replace pads (in extreme cases, grind it down with sandpaper). It is strictly forbidden to clean the pads with solvents! Eliminate the cause of oiling (replace the axle shaft seal) |
| Ice or salt crust formed on the surface of the pads (in winter); the pads got wet | Check the brakes at low speed when starting to move. In the rain and after driving through deep puddles, dry the brakes by lightly pressing the pedal |
| Low quality of the pad material | Replace the pads (better to have everything on one axis at the same time) |
| Blockage of brake lines: tubes (because of dents) or hoses (due to swelling or delamination of the rubber) | Replace damaged tubes and hoses |
| Piston jamming in the cylinder, pads in the caliper | Replace the cylinder, clean the contact surfaces of the pads and caliper, lubricate them with SHRUS-4 before installation |
| Complete wear of brake linings (brakes grinding) | Replace the brake pads (better to have everything on one axis at the same time) |
| The brake shoe lining has separated from the base | Replace the pad (better to have everything on one axis at the same time) |
| The pressure regulator drive is incorrectly adjusted | Adjust the drive |
| The pressure regulator is faulty | Replace the regulator |
| The vacuum booster is faulty or the hose connecting the booster to the intake manifold is leaky | Check the integrity of the hose, its fit on the fittings, and the tightening of the clamps. To check the booster: turn off the engine, press the brake pedal 5–8 times and, holding the pedal pressed, start the engine. If the booster is working properly, the pedal should noticeably "move" forward after starting the engine. Replace the faulty booster |
Incomplete release of braking of all wheels | |
| Incorrect position of the adjusting bolt relative to the vacuum booster cover | The end of the bolt should protrude relative to the end of the cover by 1.25–0.2 mm |
| The rubber seals of the cylinders swelled due to oil, gasoline, etc. getting into the brake fluid. | Replace cylinders, hoses, completely drain brake fluid, flush the system with fresh fluid and bleed |
| The master cylinder piston is stuck (due to corrosion, breakage of return springs, mechanical impurities entering the liquid) | Replace the master cylinder, bleed the system |
| Brake pedal sticking: return spring broken or stretched, pedal bushings badly worn, not lubricated, axle corrosion | Replace the defective spring, bushings, put fresh grease in them Litol-24, Tsiatim-201, -221, Fiol-1U |
Braking of one of the wheels with the brake pedal released | |
| Wheel cylinder piston jamming | Replace the cylinder |
| The rubber seals of the cylinders swelled due to oil, gasoline, etc. getting into the brake fluid. | Replace cylinders, hoses, completely drain brake fluid, flush the system with fresh fluid and bleed |
| Blockage of brake lines: tubes (because of dents) or hoses (due to swelling or delamination of the rubber) | Replace damaged tubes and hoses |
| Rear brake shoe lining delamination | Replace the pad (better to have everything on one axis at the same time) |
| The rear brake shoe tension spring is weak or broken | Replace the spring |
| Deformation of the spacer bar, misalignment of the pads due to deformation of the brake shields | Straighten or replace the spacer bar, brake shields |
| The parking brake is overtightened, the cables are jammed in the sheaths | Adjust the tension of the cables, lubricate them with engine oil, if the sheath is damaged or the cable wires are frayed, and also in case of severe corrosion - replace them |
The parking brake does not hold well | |
| Incorrect drive adjustment | Adjust the drive |
| Drive cables are jammed in the sheaths | Lubricate the cables with engine oil; if the sheath is damaged or the cable wires are frayed, or if there is severe corrosion, replace them |
| Brake drums and linings are oily | Clean oily discs and drums, replace pads (in extreme cases, grind it down with sandpaper). It is strictly forbidden to clean the pads with solvents! Eliminate the cause of oiling (replace the axle shaft seal) |
| Ice or salt crust formed on the surface of the pads (in winter); the pads got wet | Check the brakes at low speed when starting to move. In the rain and after driving through deep puddles, dry the brakes by lightly pressing the brake pedal |
| Complete wear of brake linings (brakes grinding) | Replace the brake pads (better to have everything on one axis at the same time) |
When the parking brake lever is released, the wheels are not released | |
| After the car had been parked for a long time, the brake pads stuck (or frozen) to the drum | When pulling the parking brake lever or cables, try to gently (to avoid damaging the brake pads) turn the wheel. Check the ease of movement of the cables in the casings, the pistons in the wheel cylinders, the rigidity of the return springs of the parking brake cables and the tension springs of the shoes. When parking the car, if possible, do not tighten the brake, but engage the gear |
| Incorrect drive adjustment | Adjust the drive |
| Drive cables are jammed in the sheaths | Lubricate the cables with engine oil; if the sheath is damaged or the cable wires are frayed, or if there is severe corrosion, replace them |
Vehicle deviation from straight-line motion (on a flat road) | |
| Uneven tire pressure | Set the pressure to normal |
| Violation of the longitudinal tilt angles of the steering axis and/or camber of the front wheels | Adjust the steering axis and/or camber angles of the front wheels |
| Significant difference in tire wear | Replace a worn tire |
| Uneven settlement or breakage of suspension springs | Replace both springs |
| Suspension and/or car body parts are deformed | Straighten or replace deformed body parts and panels |
| Rear axle displacement due to breakage of rods or their mounting brackets | Replace the rods, weld the brackets |
| Wheel braking due to wheel cylinder piston jamming | Replace the cylinder |
| Rear wheel drag due to weakening or breakage of the rear brake pad tension spring | Replace the spring |
| Blockage of brake lines: tubes (because of dents) or hoses (due to swelling or delamination of the rubber) | Replace damaged tubes and hoses |
| Wheel cylinder piston jamming | Replace the cylinder |
| Blockage of brake lines: tubes (because of dents) or hoses (due to swelling or delamination of the rubber) | Replace damaged tubes and hoses |
Car drifting or skidding when braking | |
| Wheel seizure due to separation of the lining from the base of the brake shoe | Replace the pad (better to have everything on one axis at the same time) |
| Oiling of brake discs, drums, linings | Clean oily discs and drums, replace pads (in extreme cases, grind it down with sandpaper). It is strictly forbidden to clean the pads with solvents! Eliminate the cause of oiling (replace the axle shaft seal) |
| Ice or salt crust formed on the surface of the pads (in winter); the pads got wet | Check the brakes at low speed when starting to move. In the rain and after driving through deep puddles, dry the brakes by lightly pressing the brake pedal |
| Different tire pressure on left and right wheels | Set the pressure to normal |
| Significant difference in tire wear | Replace a worn tire |
| Brake disc deformation | Replace the disk (better in pairs) |
| Brake drum ovality | Grind or replace the drum |
| Uneven front suspension spring sag | Replace both springs |
| Wheel alignment angles are incorrect | Adjust the wheel alignment angles |
Rapid wear of tire tread | |
| High speed, starts with wheel slippage, skidding braking, cornering with skidding or understeer | Change your driving style. Adjust tire pressure, wheel alignment, and suspension components more often |
| Tire pressure is different from the norm | Set the pressure to normal |
| The front wheel alignment angles are incorrect | Adjust the wheel alignment angles |
| Increased axial play of the wheel (severe wear of front wheel bearings or loose hub nut) | Tighten the wheel hub nut, replace the bearing if necessary |
| Contact of materials aggressive to rubber – bitumen, oil, gasoline, solvents, acids, etc. – on the tread. | Replace the tire |
| Overloading the car | Do not overload the car |
Uneven tire tread wear | |
| Increased wheel imbalance | Balance the wheels |
| Deformation of tire, rim | Replace the wheel |
| Different tire pressures | Set the pressure to normal |
| The front wheel alignment angles are incorrect | Adjust the wheel alignment angles |
| High speed movement in turns, passing them with skidding or demolition of wheels | Change your driving style. Adjust tire pressure, wheel alignment, and suspension components more often |
| Increased axial play of the wheel (severe wear of front wheel bearings or loose hub nut) | Tighten the wheel hub nut, replace the bearing if necessary |
| Wear of joints, deformation of suspension or body parts | Replace joints, straighten or replace deformed suspension parts, side members, body panels |
| Steering play (see also "Excessive steering wheel play") | Replace worn joints, tighten threaded connections, adjust the clearance between the pinion and rack in the steering mechanism |
Increased steering wheel free play | |
| There is a large gap between the worm and the roller in the steering gear | Adjust the clearance, if adjustment is not possible, replace the steering gear |
| The pendulum arm bushings are worn out | Replace bushings or swing arm |
| The steering rod joints are worn out | Replace the rods |
| The fastenings of the steering gear housing and/or the pendulum arm bracket to the body side members have become loose | Tighten the fasteners |
The steering wheel turns hard | |
| The steering gear clearances are not adjusted correctly | Adjust the gaps |
| Nicks on surfaces, deformation of the worm and/or roller of the steering mechanism | File off minor damage; replace the steering gear if it is significant |
| Too tight pendulum arm bushings, lack of lubrication | Adjust the nut tightening, lubricate the bushings with Litol-24 and put grease in the cavity between them. To check the tightening force of the nut, remove the pendulum arm bracket from the car. The arm should rotate when a load of 1–2 kgf is applied to its end and should not turn under its own weight |
| Low tire pressure in front wheels | Set the pressure to normal |
Coasting of a vehicle on a flat horizontal section of road from a speed of 50 km/h for less than 500 m (at an air temperature of at least 20°C and after a run of at least 20 km) | |
| Braking of one or more wheels | See "Incomplete release of braking of all wheels", "Braking of one of the wheels with the brake pedal released" |
| The front wheel alignment angles are incorrect | Adjust the wheel alignment angles |
| Low tire pressure | Set the pressure to normal |
| The gearbox is filled with oil of the wrong viscosity | Replace the oil with the one recommended in the operating instructions |
Oil leak from rear axle | |
| Damaged or worn axle shaft or gearbox seals | Replace the cuffs |
| Scoring, scratches on the surfaces of the shafts on which the seals operate, shaft runout | File and polish minor damage. The new seal can be slightly (up to 1 mm) under-pressed (adding spacers if necessary), so that its edge works on the unworn part of the shaft. Replace the deformed parts |
| Increased pressure in the rear axle due to clogging of the breather | Clean or replace the breather |
Traces of shock absorber fluid are visible on the shock absorber | |
| Fluid leak from shock absorber (due to wear of the stem seal, reservoir sealing ring, nicks and damage to the chrome coating of the stem) | Minor "sweating" of the shock absorber in the upper part (if there are no leaks) if its characteristics are maintained, it is not a malfunction. You can check the shock absorbers on a special stand or - roughly - by rocking the car by the wing. No more than 1-2 free vibrations of the car are allowed. In case of significant fluid leakage and/or loss of efficiency, replace the shock absorber |
(The article is taken from an online resource VAZbook)