The use of a driveshaft in a car began in 1898. The part is not distinguished by the complexity of its design or the presence of a special component, but it plays a very important role in the proper operation of the car.
The driveshaft is an integral part of any car, connecting the gearbox to the axle.
The cardan shaft consists of the following parts:
- rear and front shaft;
- crosses;
- sliding forks;
- fork flange;
- spline connection;
- suspension bearing.
There are several types of driveshafts: two-bearing, three-bearing (installed on most vehicles) and four-bearing (typical for SUVs).
Each component of the driveshaft
performs its function and is an important element in the operation of the entire mechanism.
Cross joints and fork joints control torque transmission.
The spline connection ensures smooth operation of the entire vehicle while moving on uneven terrain. The purpose of this part is to lengthen the driveline transmission when driving the vehicle uphill, and shorten the transmission when driving downhill.
The elastic coupling acts as a protection that absorbs the shock wave when the clutch is shifted.
Thanks to the suspension bearing, additional support is created, with the help of which the shaft is held in place. Depending on the shaft design, the number of bearings is calculated. The part is attached to the bottom of the body with its base.
The material for the central part of the propeller shaft is steel pipes.
In the event of a breakdown, you can contact a car service center, where you will quickly have the crosspiece and suspension bearings replaced.
The driveshaft and its crosspiece - why are they so important
The driveshaft - in common parlance just a cardan - is an important part of the transmission in the design of rear-wheel drive and all-wheel drive vehicles. Its task is to transmit torque at an angle. It is also called the “car support”, as it provides the rigidity necessary for proper functioning.
The cardan consists of two hollow pipes connected by a cross. The crosspiece is the heart of the cardan shaft, because it is responsible for transmitting rotation. In essence, this is a cross-shaped hinge that moves due to bearings. In addition to its main functions, it helps the car maintain balance on uneven roads and dampens the resistance of the driveshaft.
The driveshaft in general and the spider in particular are the heart of the transmission. These devices provide a smooth and even ride of the vehicle, sensitive control and a comfortable ride. Their failure is fraught with many troubles: loosening of the fastening, play between the two shafts and an increase in the load on the crosspiece can lead to a breakage of the shaft and, as a consequence, to an emergency. How to prevent this and notice the problem in time?
Preparing the lugs and forks and installing a new spider
The repair will be carried out poorly if the eyes and fork are not cleaned of dirt and rust. This is done with a metal brush or sandpaper. All internal surfaces also need to be cleaned and lubricated before installing a new cross. Do not forget about the grooves of the retaining rings; they need to be cleaned with an awl or a thin screwdriver. Next, the cups are removed from the new cross, and the cross itself is inserted between the eyes. When removing the cups, you need to make sure that the bearing needles do not fall apart. If there is no lubricant under the new cups, the part should be changed, or lubricated yourself. The cups are placed on the crosspiece, then they need to be pressed in with a hammer until the locking grooves open. The repair of the cross is completed by replacing the retaining rings.
This is interesting: Technical characteristics of TD27 2.7 l/85 l. With.
Signs of a broken universal joint
An experienced driver who knows his car well usually has no difficulty in noticing even the slightest change in the car's performance, but problems with the driveshaft often become noticeable when it is too late. Experts note that the easiest way to determine if a crosspiece is broken is by sound. The driver himself cannot always hear it, so it is better to check the car with an assistant located outside the cabin. What should the following sounds convey:
- Knocking and knocking noises when the gearbox is turned on clearly indicate that the crosspiece is faulty. Its inability to hold the shaft creates a misalignment - backlash, which is the cause of sharp impacts.
- Creaking noise when driving or accelerating may be due to deformation of the spider bearing. If you do not carry out an urgent replacement, the hinge will only continue to deteriorate.
- Vibration of the chassis can be a manifestation of many malfunctions, but the most common is wear of the crosspiece bearings.
Important! Even this modest information is a reason to contact a car repair shop for a more thorough and detailed inspection of the cardan. You can conduct a visual inspection yourself. Pay attention to the external deformation of the part and check for oil leaks.
Heavy knocking or knocking immediately after turning on the gearbox, vibration when accelerating
The main reason for shocks or knocks when there is a load on the driveshaft is backlash!
- The most common cause is a faulty driveshaft spider. When it is destroyed, a strong backlash appears and, as a result, impacts. The crosspiece needs to be replaced.
- Loosening the propeller shaft bolts. Carefully inspect all bolts and tighten securely. If the bolts have not been touched in the near future, then the problem is not with them.
- The movable splines of the propeller shaft are severely worn. To eliminate the problem, replace the cardan splines.
- There is a lot of play in the bearing kit. Usually accompanied by frequent replacement of the propeller shaft bearing. Treat by installing the kit under the support.
Causes of crosspiece malfunction
Often the damage is so serious that only a complete replacement of the hinge, or even the entire cardan, can correct the situation. Of course, no one will be happy with the extra expenses, not to mention the downtime of the car. Therefore, it is a good idea to try to minimize the risk of failure. The two most common causes of hinge failure are:
- The crosspiece is a fairly strong part, but even it is subject to wear. This is especially noticeable on trucks. Mechanical shocks and careless driving significantly reduce the service life of the joint.
- Incorrect installation and balancing. Most often, used cars suffer from this, whose owners independently repaired the cardan. When installing the crosspiece, accuracy and reliability of fastening is important, otherwise vibrations will occur that can destroy the part.
Important! It is worth noting that unprofessional installation or replacement of the spider can lead to more extensive malfunctions of the entire transmission system, so you should not rely on your own strength or entrust this work to people without the proper experience and the necessary tools. Don’t create unnecessary problems for yourself - contact specialized repair centers.
Vibration is the main failure of the cardan
Before troubleshooting the driveshaft, make sure there is no imbalance on the wheels.
If vibration of the driveshaft occurs in a certain speed range (from 60 to 80 km/h, from 90 to 120 km/h), this is good vibration, which is eliminated by balancing the driveshaft. As a rule, this kind of vibration appears after repairing the driveshaft: replacing the crosspiece, bearing, shortening and lengthening, or disassembling and reassembling the driveshaft not according to factory marks.
If the vibration began suddenly at a certain speed and constantly increases as it increases. However, the driveshaft was not repaired. The following faults need to be checked:
- Impaired smoothness and play in the crosspieces. Worn hinges need to be replaced.
- Ingress of a foreign body (up to grains of sand) when installing the cardan on the axle, transfer case, or gearbox. Clean the cardan flanges and receiving flanges on the vehicle from dirt.
- Play in the movable splines or fixed splines (support set) of the propeller shaft. The spline connections need to be replaced.
- Separation or extreme corrosion of balancing plates. Inspect the cardan; when the plate is torn off, the place of its attachment is very clearly visible. Eliminated by balancing.
- Dirt stuck to the driveshaft. Clean the shaft from dirt.
- A bent pipe due to a mechanical shock when hitting a cobblestone or curb. In some cases, it can be treated by straightening the pipe using a hydraulic press. On average, if the pipe is deformed by more than 1.5 millimeters, it is replaced with a new one.
Repair or replacement of the cross
The degree of damage to the hinge and the likelihood of successful repair can only be determined by removing and disassembling the crosspiece. Usually this procedure is carried out on a dismantled cardan.
The decision to replace or repair is made based on the appearance of the hinge and its parts. If we are talking about one or more worn out bearings, then this problem can be easily solved without complete replacement. However, if deformation of the crosspiece is visible - dents, cracks, bends - then repair is not enough.
Unfortunately, not all car owners follow these rules. There are many examples of unsuccessful attempts at makeshift repair of the spider, which only led to faster destruction of the driveshaft, driving problems and emergency situations. Any mechanical impact, especially on an already damaged hinge, reduces its ability to bear loads, even if as a result of these actions its appearance is restored. If repairs are possible, they must be carried out by trained personnel.
Important! Regardless of whether the part was repaired or replaced with a new one, after installing it and the cardan it is necessary to carry out balancing. It is almost impossible to do it efficiently on your own. This is why even the best and most expensive garage-installed joints can fail after a few months of driving.
We carry out replacement
To begin replacing the crosspieces, you need to provide yourself with access to the cardan and unscrew it. There are craftsmen who prove that you can change crosspieces without removing the cardan. As for me, this method is for extreme sports enthusiasts who do everything in one place; we’re not one of them, are we?
Removing the cardan
For example, I took the driveshaft of the Gazelle car, the crosspieces are designed the same, as I already said, and the fastening may differ from other cars, but not so much as to describe the removal of each shaft separately. The procedure is as follows:
Position the car so that you have access to all the universal joint bolts. For safety reasons, block the wheels of the car
Engage the gear, no matter which one, you must ensure that the shaft does not spin on its own. Mark the location of all the elements that you will remove so that when reassembling they are also located relative to each other
The driveshaft, a part that is balanced in the assembled state, simply turning the driveshaft upside down will upset this balance. Then strange vibrations and rapid breakdowns of the crosspieces will begin. Why create unnecessary problems for yourself? Only after these steps can the cardan be unscrewed and removed. First, unscrew the suspension bearing, which is held in place by two nuts. Now there are 4 bolts from the bridge flange. Pull it out of the gearbox splines
Removing the cross
Further, it is much more convenient to work in a vice. When clamping the shaft, do not overdo it, you can crush:
- Now you will need pliers, a strong large screwdriver, a round attachment and a hammer; instead of an attachment, a tube or rod will do. The diameter of the attachment should be smaller than the diameter of the eyes, but not by much.
- It is convenient to use round-nose pliers to remove the retaining rings without damaging them.
- This can also be done with two flat screwdrivers, only then can the retaining ring be thrown out.
- If the locking ring is tight, tap it through the adapter with a hammer. Then the cup will sag and it will be easier to remove the stopper.
- The rings can be removed all at once, after which we need to knock the cups out of the eyes.
- Using the same tip and hammer, push the cup inward, from the back of the cross the cup will come out, it may fall out, but usually it does not come out all the way. You should not hit the cardan; remember to balance it.
- It is easier to pull out the released cup with pliers, a gas wrench, or clamp it in a vice and pull it by the cardan.
- Use the same method to remove the remaining cups.
- After removing the crosspiece, take a wire brush and clean the dirt from the lugs and fork.
- You can even go a little inside with fine sandpaper, then clean the grooves for the retaining rings and thoroughly wipe the shaft from dust, you can even wash it with gasoline.
- There are special pullers for crosspieces, but there is no point in purchasing them; even in service stations they are used extremely rarely.
Installing a new one
Installation is also not difficult; anyone can do it:
Take the new crosspiece in your hands and carefully remove the two cups from opposite sides. The main thing is not to scatter the bearing needles
Check under the cup for grease. It happens that the manufacturer forgets to lubricate, and the bearing is almost dry, I have seen this myself more than once. If there is no lubricant, you need to carefully apply it with your finger, otherwise the needles will fall out during assembly and you will have to disassemble again. Place the ends of the cross without cups into the eyes on the cardan, then carefully insert the cups into the eyes. They should move easily with your fingers as much as possible. Then, using a tool and a hammer, they lower it a little deeper than the grooves of the retaining rings. Insert the retaining rings. If you cannot insert the ring on one side, there is no need to hammer as hard as you can; on the contrary, carefully disassemble the cross. It happens that the needle of the cross falls out of the row and does not allow the lid to get into place, forcing the bearing will only break the cup and flatten the needle, then you will have to buy another one to replace it. Repeat the process with the other ends of the bearing. After replacement, all that remains is to return the cardan to its original position and screw it on.
To make the crosspieces last longer, do not forget to fill them with lubricant through the existing grease nipples. The lubricant is filled with a special syringe. It is not necessary to look for a lubricant specifically for crosspieces; ordinary “litol” will help. Repeat packing every 5-6 thousand mileage.
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How to choose a crosspiece for your car
If after all the diagnostic procedures it becomes clear that the car cannot drive for a long time without a new part, it’s time to think about choosing a replacement joint. What should you pay attention to?
- Manufacturer. It is best to give preference to well-known names. Among the most popular and high-quality ones are GWB, GKN, HD Parts.
- The appearance of a part can tell a lot. If traces of rough machining, burrs and other defects are visible, then this is a product of low quality.
- The choice of cross is made according to the shape and size of the bearing cups - they must correspond to a tight fit.
Important! Problems with cheap crosspieces may begin already at the stage of their installation, so we cannot recommend that you choose a part based on its price. Remember that not only its durability, but also the driving performance of the car and even your safety depend on the strength and reliability of the universal joint.
