For many collectors and enthusiasts, their vehicles’ originality is paramount. “Matching numbers” is an important predicate here. This means that the engine, chassis and transmission are the same parts as when delivered. However, this desire for originality extends to more and more components. That’s why Silke Lukas, managing director of Autoteile Jakobs, has also turned her focus to preserving as many original parts as possible in Porsche sports cars. Her hobbyhorse is the restoration of steering racks.
Silke invited us to take a close look at the reconditioning of a steering rack for our partners at Christian ABT Classic. She gave us a tour of the hallowed halls of their production. Autoteile Jakobs has specialized in steering systems for almost two decades. Therefore, the managing director can draw on a wealth of experience. She explained to us very clearly how to recognize a worn steering gear, what pitfalls there are in steering rack repair and why it is such an important piece of the puzzle for a successful Porsche restoration.
Our team spends most of its time at a desk. Of course, when we’re on the road visiting our dealers, we usually see the finished end product – the Porsche sports car for sale. Here and there, we also get to look behind the scenes at the construction of Porsche-based Backdates/Restomods. But we have not yet been allowed to see the rebuilding of individual components either.
Shortly after the welcome, we had our first “aha” moment. Silke Lukas shows us – almost casually – a steering rack from a Porsche 959. “This part was used almost unchanged in the Porsche Carrera GT, as well”, says the young entrepreneur. There are a good two decades between the two vehicles. A fine example of Porsche’s way of working. What’s good doesn’t have to be developed from scratch.
The steering rack is a central component of a vehicle’s steering system. Porsche sports cars have been using a rack-and-pinion steering system since the mid-1960s. This has a spindle with a pinion at the end of the steering column. This engages with the rack and thereby moves the steering rod in the housing from side to side. Through this movement, the steering rack shifts the externally mounted tie rods. The result is that the wheels point in the direction in which the steering wheel is turned.
So the basic structure of steering racks is a very elegant design. It contains few moving parts and is self-contained. Therefore, they can also provide many years of trouble-free service. But the steering bellows, also known as the steering boot, can become cracked with age. Water and dirt then get into the steering rack. Corrosion inside and especially on the steering rod is the result. The seals are also subject to wear. If they leak and hydraulic oil escapes, they have to be replaced immediately to prevent further damage.
We ask the boss: How do I recognize a defective or worn steering rack? “If a steering rack is worn, different symptoms can be the result. Often, the steering loses accuracy around the center position, or doesn’t react at all there. When you steer, nothing happens at first. This play increases gradually over the years.”
“Delayed implementation of steering commands is also an indication of increased wear. But cracking or grinding noises, vibrations or increased steering forces also indicate that the steering rack should be repaired”, she says, summarizing potential symptoms of a defective steering rack.
Autoteile Jakobs also offers the repair of steering racks for private consumers in the Lenkgetriebe.net webshop. But over the years, most of the business shifted to working with workshops and restoration businesses.
For good reason: “Especially when restoring classic vehicles, it is important to preserve as much originality as possible. The more original parts that can remain in the vehicle at the end, the better. The 1:1 reconditioning, i.e. the refurbishment of a sent-in part, is ideal for this. This is because all wearing parts such as seals and sleeves are replaced, but the original housing is retained.”
But financial considerations can also play a role. “A new steering rack for an air-cooled Porsche quickly costs several thousand euros as an original part. In comparable cases, the repair usually costs less than 1,000 euros,” says Silke Lukas. When asked about the complaint rate, she proudly replies that it is “zero percent” in the Porsche sector.
Word of this quality standard has spread. “In the meantime, our clientele includes not only end consumers, but also numerous workshops, restoration businesses and Porsche Centers alike” reports the Saarland native.
“The complaint rate in the Porsche sector is zero percent for steering racks from Autoteile Jakobs.”Silke Lukas, managing director of Autoteile Jakobs GmbH
At the beginning of each overhaul, the old part is closely inspected from the outside. “This part looks very good externally. We probably won’t even have to sandblast it,” Silke explains. She also says that there are two camps in this area. On the one hand, those who want a look as good as new. “With a classic, however, we recommend destroying as little of the original finish as possible – assuming the old part is still in a usable condition,” she says.
As a counterexample, she shows us a defective steering rack that has been improperly machined. “The housing is irreparable and must be replaced”. A sensitive blow for the owner. Because it makes the replacement considerably more expensive than originally thought. If only the appearance is affected, the experts at Autoteile Jakobs blast the housing with glass beads. It is then powder-coated – all in-house.
After a visual inspection, the steering rack for the restoration project from ABT is first cleaned from the outside and then disassembled. Steering rack, housing, spindle and co. are neatly lined up, their condition documented. Only slight corrosion is visible on the steering rod. “We can grind that,” says the expert. Then the components are cleaned again. Therefore, they are packed into the rotating basket of the huge parts washer. “Here, cleaning is done without chemicals. Only hot water is used in the washer.”
Now the most exciting part begins – the repair. The steering rod’s and spindle’s toothing is still within specification. So these parts can be used again. But the corrosion on the steering rod has to be ground off first. This is done by hand on the lathe. The rust deposits are gone in no time. If there is more corrosion, this step would be problematic. If too much material had to be removed, the part would no longer be dimensionally accurate and would have to be replaced.
After that, the specialist polishes all sealing surfaces and takes care of any damage to the housing. Even a small burr can damage the sleeve during assembly and cause leaks. All parts are then lined up neatly on the assembly bench. The technician reassembles the steering rack with skillful hand movements.
Of course, new bearings and O-rings are used. Silke explains that there are always large stocks on hand. This allows her technicians to compensate for minimal deviations from the factory specification. To guarantee future-proofing, Autoteile Jakobs always replaces felt seals – where possible – with shaft seals as well. A reconditioned steering rack from Autoteile Jakobs is thus better, i.e. more durable, than what was installed originally.
But it is not only in terms of quality that Autoteile Jakobs can offer steering racks that are above the original standard. Thanks to their years of experience, Silke Lukas’ team also knows about possible alternatives. In plain language, this means: “If, for example, a racing team needs a special steering system for historic motorsports in a classic Porsche 911, we can show which components can be installed instead of the original part.
“There are also scenarios in which a steering rack from another model can be used that offers a more direct steering ratio, for example,” reports the strong woman behind Lenkgetriebe.net. This solution is particularly in demand for Backdates. After all, the spirit of this particular Porsche genre is usually “new technology with classic looks”. But also in the context of a defect-conditioned exchange it offers itself to think through this option. Depending on the model, Autoteile Jakobs can even remanufacture defective parts in-house.
Meanwhile, our demonstration object was reassembled with impressive routine and accuracy. By the way, Lenkgetriebe.net also uses different material compositions for the steering boots. Externally, they are indistinguishable from the original part, but last many times longer. After the tie rods are mounted, the steering is centered and the track is adjusted.
Before delivery, quality assurance comes into play once again. On the hydraulic test bench, the technician checks whether everything is oil-ight. If hydraulic fluid leaks or there is a drop in pressure, reworking is required. At the same time, a check is made to see whether the steering torques also correspond to what the manufacturer specifies. Everything is in perfect order with the steering rack for Christian ABT Classic. It is prepared for shipping and receives the “socks”. That’s what Silke’s team calls the purple mesh that is stretched over the components for protection.
But installing a steering rack is not for beginners. “99 percent of all complaints we receive are due to improper installation,” explains the managing director. “The installation of steering racks quickly presents even experienced hobby mechanics or workshops with expensive problems. But removal also has its pitfalls. Sometimes it goes so far that the steering rack is irretrievably destroyed by incorrect removal.”
The day in the production of Autoteile Jakobs was extremely instructive. We were able to watch experienced masters of their trade rejuvenating and preserving assemblies. This was a very welcome change, as workshops hardly ever repair parts anymore, but often just replace them. Silke Lukas and her team make it possible for us Porsche enthusiasts to preserve the original substance of our treasures. And without any loss of function. Instead, real improvements to the standard condition are even possible.
So if your repair shop diagnoses a defective steering rack and offers a replacement part, think carefully about whether remanufacturing would be a better way to go. It offers real functional advantages, longer life than the original and is even cheaper than a new part. And if the old part is irreparable, Autoteile Jakobs may has a reconditioned part in stock.