At the beginning of the movement, when you depress the clutch pedal, you engage first gear and release the pedal, vibrations appear when starting. As a result, drivers rack their brains for a long time and cannot figure out what the essence of such a problem is. In fact, there are a large number of causes of vibration when starting off. This may be due to the engine, gearbox, and clutch. To fix the problem correctly, you need to study this problem.
Causes of vibration when starting off associated with the engine
If the malfunction is related to the motor, then it is worth checking the integrity of its mountings to the car body.
Broken pillows or broken brackets of their mounts do not provide the required stability of the engine, respectively, it begins to shake on the sides, which complicates the work of the clutch. The same consequences occur when the engine is troit. Therefore, you need to check the performance of all its cylinders.
Engine troubleshooting
Pre-jacking the engine, the old, broken pillows are unscrewed. In their place are new ones.
Now, if the engine is troit, you must first determine what the reason is. This occurs due to poor armor wire, defective spark plugs or wear of one contact in the distribution interrupter. In the case of an injection engine, nozzle clogging is possible. To determine which of the cylinders does not work, you can in a simple way - alternately removing the armored wire from the spark plug and listening to the reaction of the engine. If the engine starts to run with even greater interruptions, then this cylinder is in order. If, after removing the armored wire, he did not react in any way, then this cylinder does not work. Now, having determined the idle cylinder, you can begin to search for the reasons for its failure and eliminate this problem.
Grip vibrations
Very often, strong vibration when starting off occurs when there is a malfunction with the clutch. This may mean severe wear on the pressure plate and release bearing. The resource of these elements is about 100 thousand kilometers. Over time, the bearing starts to buzz, and the disc burns.
As a result, the clutch slips from the load, because at the start a lot of effort is applied to it. It is thanks to the disc that it is possible to move the car from its place. The resource of the element on commercial vehicles is significantly reduced, since they have to start with an additional load. Typically, the grip resource on a GAZelle-type car is 20,000 km. Failures associated with the clutch release drive (such as a broken cable, wear of the rubber cuffs of the working or master cylinder, wear of the hose, air in the system) do not allow the clutch to be properly disengaged on the vehicle. Perhaps it does not turn off at all. As a result, it is difficult to engage the first gear. This suggests that the system is airy.
Vibration may occur when turned on. Riding with such a malfunction is not worth it. A more common situation is the vibration of the car when starting from the moment after replacing the clutch. In this case, there may be poor tightening of the clutch basket mounting bolts, improper centering of the pressure plate. This prevents the input shaft of the gearbox from entering into engagement with the splines of the clutch plate. Such consequences still occur as a result of a breakdown of the diaphragm spring petals or damper elements in the torsion limiter.
Clutch troubleshooting
In case of drive malfunctions, it is necessary to replace damaged parts: a cable, or, if the clutch is hydraulic, worn out rubber cuffs, springs, hoses or the master and slave cylinder assembly.
It is recommended that the entire master or slave cylinder be installed. Replacing the rubber cuffs will only solve the problem briefly. After all, the working surface of the liner inside the cylinder is already worn out, and it will only accelerate the wear of the new cuff. After work, it is necessary to pump the hydraulic system so that there is no air left in it. Because of it, the clutch disengagement operation will be incorrect. In the event of a breakdown of the diaphragm spring petals or the damper springs of the torsion limiter, the clutch should be replaced completely together with the basket. When installing a new assembly, be sure to center the pressure plate.
This is done using a special mandrel or gearbox input shaft for this vehicle. The mandrel is inserted into the clamping disk and the diaphragm spring, and only then the clutch basket is screwed to the engine flywheel. Then it is tightened evenly and well to prevent bolts from being unscrewed during operation.
Gear Shift Shock
In the case of a transmission malfunction, vibrations can also be felt when starting off. They are associated with heavily worn synchronizers inside the box. As already described, during the start a large load is applied to the clutch and the gearbox. With worn synchronizers, first gear will be difficult to engage. Do not exclude a malfunction of the gears of the gearbox. They can slip, in connection with which vibration occurs on the body.
Transmission Troubleshooting
The first difficult task is to dismantle the gearbox from the car. Depending on the drive of the car, the work of removing the transmission is different. Before starting work, be sure to drain the oil from it. On a rear-wheel drive car, the universal joint is first unscrewed, the gear lever, and then the gearbox itself is unscrewed from the engine. In the case of a front-wheel drive car, the joints of equal angular speeds are unscrewed and removed, the shaft connecting the gear lever to the gearbox is dismantled. And only then the transmission is unscrewed from the engine and removed.
Having disassembled the gearbox, you need to inspect the gears and synchronizers for signs of wear. Damaged and worn parts should be replaced. At the end of the work, everything is assembled and installed in its place in the reverse order. When the gearbox is in place, an ideal option would be to replace the oil in it.
Vibrations transmitted to the steering wheel
Steering vibration occurs as a result of the impact of body shocks due to the occurrence of all of the above malfunctions. However, such a problem can occur in the event of malfunctions of the steering system itself, namely, with wear of the parts of the rack and pinion mechanism, depending on its type or violation of the trapezium mounts. Below we consider this problem in more detail.
Steering troubleshooting
If the type of screw-nut mechanism, then during long-term operation the wear of friction parts increases the gap between the worm and the driven gear. It is eliminated by tightening the adjusting bolt in the cover of the steering gear housing and using high-quality lubricant. The main thing is not to tighten the bolt during tightening. Otherwise, the rotation of the steering wheel will be difficult and the wear of parts will only increase.
If the gear-rack mechanism type, then strong wear increases the gap between the gear rack. The malfunction is also eliminated by tightening the adjusting bolt. However, there are mechanisms where there is no clearance adjustment. They are replaced in the assembly, or disassemble and grind on machines. Poor fastening of the steering trapezoid supports is caused by poor tightening of the bolts. Also, this is a breakdown of the bracket or, in rare cases, the spar. It is eliminated by tightening bolts and welding broken parts. What to do if vibration occurs when starting off (VAZ 2101-2109)? Let's take a look below.
VAZ family cars
On VAZ cars, vibrations occur for the same reasons associated with a malfunction of the engine mount pads, the engine itself, gearbox and clutch. In case of vibration, it is necessary to check the vehicle units for malfunctions and eliminate them.
Vibration when starting off automatic transmission
In an automatic gearbox, shocks at start-up occur when the clutches, clutches and planetary gears are severely worn. The matter is also a malfunction of the hydromechanical transmission and the electronic control system inside the gearbox or in dirty oil channels coming from the pump. This is caused by improper use and use of poor quality grease.
Heavily worn rubbing parts begin to slip when the gearbox is loaded. Violation of the valves of the electronic control unit does not allow the necessary oil pressure to form in the system, and during a torque converter malfunction, the torque is poorly transmitted from the engine to the gearbox. This is caused by a strong backlash of the shaft bearings, as well as a breakdown of the petals of the drive and driven gears of the torque converter.
Auto Gearbox Troubleshooting
Before starting repairs, it is advisable to go to a service station and diagnose the box for errors. Faults of an automatic gearbox are eliminated by searching for worn and faulty components, then replacing them. It is worth changing only for high-quality spare parts from original manufacturers. Do not buy cheap counterparts. During replacement, it is also worth paying attention to the bearings. Otherwise, the new part may fail prematurely.
Repair must be approached comprehensively, especially in the case of an automatic transmission. Here you need to sort through all the details for wear and play, replace all rubber products, such as:
- Oil seals.
- Cuffs.
- Rings.
- Gaskets.
- Sealants.
After the repair is completed, the gearbox oil must be replaced.
Also, at a service station, diagnose and reset errors stored in the archive of the electronic control unit. In the future, you should carefully operate the gearbox, avoid jerking while starting, do not accelerate the car sharply, and before starting the movement, hold the brake pedal depressed for about one or two seconds so that the pressure required for the gearbox to work is formed in the oil system.
Conclusion
So that in the future there will be no extraneous noise and vibration when starting off, you need to carefully monitor the condition of the components and assemblies of the car, service them on time, and use only high-quality lubricants. And in case of malfunctions or breakdowns, immediately eliminate them and approach work with responsibility. The use of low-quality spare parts can worsen the situation and provoke wear of other mechanisms of the car.