When checking a used car, it is not enough to equip yourself with a tool that measures the thickness of the paint layer. Away from the workshops, it is important to have a crocodile jack to lift the car with, a repair jack to support the car, as well as a sheet of cardboard or foam, on which we can lie down and crawl under. The car selected, so that the villainous rust shown in the pictures can also be detected.
Cars that look immaculate and rust-free on the outside can hold painful surprises underneath. In addition to wear on the rear longitudinal spans and the chassis, subframe rust under the engine, known as the cradle, is also a similar problem. We can now see a “cool” example of this.
Photos sent by our reader who works in a repair shop. The 1999 Mercedes A-Class, which has nearly 200,000 kilometers, reached them for a pre-purchase inspection. They put it on an elevator, and then came the surprise: the perfectly beautiful car was slightly corroded by rust. Yes, it is a car imported from Austria.
In the end, they managed to get a subframe for it from Italy, so it really is a small car. They immediately thought they were dealing with an Austrian car, because in laws, salt likes to contribute to corrosion, especially in vehicles that have been driven a lot. By the way, the bottom of the A-class is properly insulated, nice with plastic, and it was rusty only where it was not covered, but there it gets dirty.
Subframes wear out for the same reason as the chassis suspension arms. Protection against rust is absent or superficial, because it is less expensive for a car manufacturer, and in terms of cost, their raw materials are also cheap sheet steel, which is in no way made to last forever.
The suspenders are mostly hot pressed and joined by spot welding of two pressed elements. Since the panels are not welded all the way through, water gets in when the two halves are joined together and everything falls apart over time. Due to the poor raw materials, it is customary to make the additional frame thicker, so that the amount of material compensates for the material quality limitation. Which is happening for some time, but in the Hungarian car fleet, which has an average age of 14, there are already many cars that have passed the age of protection.