Bilstein says it has ‘done the test’ regarding ‘no-name’ air suspension modules from the internet

People looking for new air suspension modules online will quickly find numerous cheap products: there are plenty of online sales platforms offering car parts.
On one of these numerous portals, for example, air suspension modules for the Mercedes-Benz brand are offered for the equivalent of around
€ 235 (approximately $376AUD). Bilstein says this is an astonishingly cheap price for, as stipulated, “brand new” products, and that it is a price that should set all alarm bells ringing.
Bilstein says it wanted to know what’s behind the supposed new parts, so it carried out a test.
To do this, it began by ordering an air suspension module which was tagged as “new”. What the seller didn’t expect: the cheap air suspension module was not just installed blindly into the car; it had to withstand one endurance test after another.
Bilstein reports the first noticeable difference between the competitor’s product and its factory-new Bilstein B4 air suspension module: Bilstein’s products are always delivered together with all details and specifications needed. These include precise information on the product and the manufacturer, as well as important quality, installation and safety instructions, it says. Bilstein reports “the inferior packaging of the competitor missed all this. And whilst our products are always accompanied by extensive installation instructions, our competitor’s contained no installation guide.”
Alongside further qualitative differences, Bilstein says the electronic connection exhibited striking differences: “on the air suspension module from the internet, we immediately noticed an old connector with an older production date and dirt entrapments. In addition, the grub screw of the competitor´s product had signs of wear. In addition, the cone area was painted, which can lead to a loss of security. Our first suspicion arose: is the supposed new part not a new part at all, but simply a refurbished used part?”

In Bilstein’s first test, the overall spring characteristics of the air suspension were measured: during the load test on the load-path testing machine there were large deviations in the spring lengths. Other than this, the folds in the protective collar pulled together in an irregular manner and even inward, says Bilstein.
“This could result in the protective collar coming into contact with the air spring bellow, rubbing and then destroying it,” Bilstein Workshop Manager, Marco Kunert, said.
“On the other hand, in our Bilstein B4 air suspension module, the protective collar regularly folds together.
The differences between the two products became even more astonishing on the acoustics test bench, reports Bilstein. Here, the measurement showed that the competing product was clearly louder than the Bilstein B4 air spring module, with Bilstein stating that the reasons for this are high friction due to a non-original built-in seal and oil loss.
Bilstein states the result of the test could only draw one conclusion: the air spring module ordered online – officially a new part – barely absorbed the oscillations and appeared to already be very worn.
These observations coincide with the results of the last test, says Bilstein, where the dynamic measurements of the characteristic curves on a load-path machine disclosed a high damping force loss: the competitor’s product purchased online only disposed 29 percent of the required damping force. “It’s obvious: The nameless air spring module was simply inoperable and thereby dangerous,” says Bilstein.

After the tests, the air suspension module was disassembled. The assessment brought alarming things to light here too, says Bilstein.
“For example, in the installed thrust rubber bearing around an original but used part, we were dealing with a circumferential tear. Viewed under light, we could also see an indentation in the pipe, which indicates an accident. In addition to this, we were able to determine that a new closure package had been installed, although unprofessionally: the shock absorbers were therefore missing approximately 10 millimetres in overall length,” reports the company.
“As we have seen, the shock absorber has no damping force. Many of the further attachments are used parts or poorly made replicas. For that reason, these parts are a significant risk to safety,” Marco said.
With a lot of detective legwork, Bilstein says it has ultimately been able to establish that the competitor’s product is actually an old shock absorber from Bilstein, which was finished in Mandern, Germany by the company in 2005. It says: so much for a new part…

For more from Bilstein, visit