Maintaining a European vehicle is admittedly more work than your normal Toyota or Chevy, but we know that these cars are worth going the extra mile for because the driving experience is so much more enjoyable when you have a well running Euro. That’s why settling for sub-standard parts simply isn’t an option for many of our customers (us included). ZF is part of a family of brands that includes ZF, Sachs, and Stablilus, and is based in Germany. Together, they are an original equipment manufacturer for many car makes, allowing you to get the best parts that money can buy while keeping everything exactly as your carmaker intended. But who really is Sachs/ZF, and why is this a brand to look out for when shopping for parts?
Sachs Ride Control:
Sachs follows the German philosophy of ‘only the best possible, all the time’. While other companies, such as Monroe (which I will bring back up in a bit), modulates the quality of their different product lines in order to have a lower priced option available for the aftermarket, Sachs makes their chassis control systems one way. The same shocks that might come on your car from the factory are also available on our shelves. However, the Monroe shocks that came on your Volkswagen are NOT the same as the parts that are available at your local Autozone. Not the best for business, but great for reputation.
There are several ways to make a shock absorber cheaply. You can skip chroming the main dampening piston rod. You can use cheaper, higher friction seals. You can forgo polishing the main damper cylinder interior. You can leave banded seals out of the valve pack. All these are traits are present in even ‘higher end’ aftermarket shock absorbers that people are putting on their cars. Sachs would never dream of allowing this to happen.
By chroming the piston rod, you protect it from corrosion, which can cause an uneven dampening as the corrosion moves past the inner seals. Same goes for honing and polishing the interior cylinder, which gets rid of all the uneven roughness caused in the manufacturing process (especially the weld bead). The main piston inside a shock absorber provides all the dampening force, so a good seal here is vital. The Monroe shocks, including the highest end Sensatrac shock featured no seal here, relying on only the tolerances of the parts to make a ‘good enough’ seal, and metal on metal contact. Sachs shocks also take the extra step to sinter the metal valves that passes the oil past the piston, making a much stronger and robust design.
Your tires move up and down between 15 and 20 times a second, independent of the chassis. The strut and shock absorber’s job is to dampen this to around 1.5hrz in a smooth fashion. Now you can see why a poorly made shock absorber will only last so long compared to an OE, which should always last more than 100k mi. They get quite a workout.
Sachs/ZF is world renowned for their powertrain systems, pioneering what is currently possible in transmission design with their new 8 and 9 speed transmissions, and it’s been that way for years. The company started out manufacturing gears for Zeppelins (the airships, not the rock band). ZF stands for Zahnradfabrik which translates to ‘Gear Factory’ in English. Regardless, they’ve put major drivetrain components in everything from Corvette ZR-1’s and Lotus Carltons, to Maserati Quattroportes and nearly every BMW ever. Currently they are supplying clutches and suspension dampeners to Formula 1 teams, which generally cost around 20k a pop. DTM, WRC, F3, and a number of other extremely demanding racing series use Sachs. Needless to say, they know what they are doing.
This dedication to the craft is the reason that this company has become such a powerhouse, and why we are happy to supply these OES parts off our shelves and onto your car. One of the most common powertrain components we sell are of course clutches, an area that ZF/Sachs has on lockdown. Manual transmission clutches are extremely tight tolerance devices, with clearances of less than a tenth of a millimeter causing drastic enough changes to feel. Because of this, the modern clutch assembly and accompanying hydraulic system must be manufactured to extremely tight specifications, something ZF is a master of. Here are some tolerances. The tolerance of the pressure plate lift should be a max of 1.8mm, the lining spring travel has a maximum travel of 1.2mm, the runout of the driven plate cannot exceed .5mm and the clearance cannot exceed .1mm or you will have issues (about the thickness of a business card). Check out this cutaway.
Everything from the thickness and uniformity of the facings and the wavy compression spring between them, to the stop pins and driven plate must be cut and assembled in a way to ensure the components last a full lifetime, around 100k miles. With modern engines getting lighter and more powerful, the vibrations tend to increase. Making a friction component that can handle a good amount of power is no problem. That’s so 1950. These days, an amazing amount of focus is put into dampening these vibrations. Without a well made torsional dampening system, your new Audi will feel terrible to drive. I digress.
When doing a clutch, it’s important to make sure you handle them with care to avoid damage, as well as grease the splines that the clutch friction disk travels on. HOWEVER, be sure to not over-grease these splines or you risk spraying grease up onto the friction material. This will cause improper break in and ultimately can shorten the life of the clutch.
The third ZF brand offered by eEuroparts.com is Stabilus. Specializing in hood and trunk lift supports, we won’t be talking about any Formula 1 technology here, but the manufacturing knowledge and attention to detail remain the same. Stabilus lift supports are quality made in Germany, and some right here in the US, so you know when you install one it’ll last awhile, and next time you are under the hood (see line one of this blog post), we all know you’ll appreciate not having it slam closed on the back of your skull. The prices are so reasonable and the job is so easy to do that there’s no reason to not change out your supports when they start to sag.
I hope this helps you to understand what goes into this brand, and more importantly what ZF does to make sure these products are of the highest quality. Be sure to check out our selection of ZF parts and their aftermarket brands, including Sachs and Stabilus, on eEuroparts.com.