As you know, side members are the most important part of the car body structure. And replacing the spar is a rush job. It would seem that such an inconspicuous detail cannot be associated with so many issues that are responsible for the correctness of the car body, but this is so. Thanks to the spar, there is not so much load on the wheel. In addition, these parts strengthen the mudguards, the luggage compartment floor and the body as a whole. These are a kind of shock absorbers. In this article we will tell you how to replace this part on cars.
Replacing this body part is done as follows: they try to align the part to a standard shape, and only then cut it out. But the cutting line must pass in certain places. After this, a new spar is installed and spot welded.
We pull out the spar with our own hands
Cars can be framed or with a monocoque body. If in the frame version the entire load is taken by the frame (all other components and assemblies are attached to it), then, accordingly, in the version with a monocoque body, the body takes the entire load. In this article we will talk specifically about the version with a monocoque body, more precisely, about the power elements in it - spars .
Spars are hollow (in most modern cars they are not hollow, but more on that later) elements, most often of rectangular cross-section. The spars are located in the front and rear of the car (2 front and 2 rear). They are located parallel to the thresholds of the car. All other body elements, components and assemblies are welded and screwed to the side members.
Considering the quality of domestic roads and sometimes careless operation of the car, all power elements of the car are constantly subject to stress.
Damage to the spar requires repair or replacement.
If the spar has shifted, but remains intact, then in any case it must be pulled out in order to return the correct geometry to the seat of this element. It is worth remembering that it is better to entrust such repairs to specialists. In a car service, the spar is pulled out on a special slipway. The car is fixed motionless on the slipway and pulled out using clamps, chains and hydraulic equipment. The car body is the most expensive part of vehicles to maintain. Consequently, its repair at a car service center can cost a pretty penny.
What types of damage to side members occur?
As we noted earlier, damage to side members occurs most often as a result of serious road accidents. Conventionally, this type of damage can be divided into three types:
- mechanical damage
associated with visual changes in the structure (deformation, curvature, etc.); - internal damage
(cracks, stress in the metal); - violation of the integrity
of the welded fastenings of the spar.
External damage is detected during visual inspection and control measurements. It is more difficult to identify internal stresses of the metal and the presence of cracks, but it is possible with the help of spectrographic study of the metal structure and photography in the infrared range.
Video - extracting the spar of a Kia Sid car without a slipway:
Unfortunately, as noted earlier, it is not possible to fully restore the spar, and therefore the motorist should pay close attention to whether there is any such damage when purchasing a used car. If the side members of the car were damaged and were later restored, it makes sense to refrain from purchasing such a vehicle.
How to pull out the spar?
This is a responsible procedure, but you can still try to carry out the repairs yourself and literally in the yard. The first and easiest way is to use cable and wood. Instead of a tree, any pole can do. The cable needs to be secured to the pole at one end, and the other to the car, or rather to the extended spar. Next, you should start the engine, turn on reverse gear and, with short, sharp movements back, slowly “pull out” the spar. In between “twitches” you need to tap it with a hammer. In this method, the main thing is not to overdo it - do not knock over a tree or pole, or “tear” the car into 2 parts. This method will not always work. For example, if the engine has moved due to damage or the drive wheels have jammed, this method will not work.
The next way to repair a spar is to use a jack. It is best to use hydraulic models, since with a small applied force you can achieve a larger load. This method can be divided into 2 more methods.
You can also resort to using another car. This method of repairing a spar is similar to the first. The difference is clear - here it is not the damaged car that is jerking, but another one. The method is ideal for a car that cannot even start after damage.
Even if the spar is not damaged , but only needs to be pulled out, then in any case after this repair it must be strengthened. The principle of a crumpled sheet applies here - even after straightening a crumpled sheet, it cannot be restored to its original strength.
As mentioned at the beginning of the article, the side members in modern cars are not hollow. In modern cars, these parts carry not only a power load, but are also an element of safety. They are a package of many inserts. In an accident, all these inserts are crushed. Thus, in the event of an accident, they become completely unusable, and in the future, after being pulled out, they will have to be replaced.
In any case, you always need to monitor the integrity of the side members , the absence of rust on them and make repairs .
Source
Pulling spars in garage conditions. Is it possible to?
I want to experiment. The problem is this. I picked up the car in a tattered condition. The left front spar is practically like a house. At the “camber” they were able to set a maximum of -2 degrees. Some services don’t want to take on repairs or charge a high price tag. Please someone tell me whether it’s realistic to do it yourself and how (well, at least it’s not ideal). And I also have a jamb with a rear door (station wagon). The left side also went away and therefore the gap between the door and the body. Mom don't worry. Can anyone tell me how to fix it?! Just don’t get scoffed at, throw it away or sell the junk - 1. No money for a good car. 2. I want to try it myself.
Car T-Corolla Van 1998 5E-FE.
Hook the chain to the spar and to some kind of post, wind it and jerk it back, just look roughly where you need to pull it (in which direction - to the right, to the left). My brother pulled out the frame of the crown this way..
If you're talking about the butt, then it seems understandable. My front seems to be neither forward nor backward, but the angle is incorrect.
Kolka, one more question. What is there to attach the chain to?
Details, please. Where are they wrapped?? To the right, to the left, to the top, to the bottom.
When viewed from the front, the top of the wheel tends toward the engine.
So it could be a bent lever, or the mudguard has moved to the side. If you are sure that you need to pull the spar, explain it so that I understand where you want to pull it
