How a Traditional Dealership Successfully Expanded Beyond Its Core Brands and Now Repairs Everything from Opels to Jaguars with Dealer-Level Confidence 

Workshop Walkthrough: Autohaus Stumpf is a forward-thinking dealership and workshop in Germany. For over 40 years, they built a strong reputation as a trusted partner for their core brands, Opel and Mazda. But in the past three years, under the leadership of Workshop Manager Rouven Bauer, they have strategically expanded their operations to meet a new reality: the growing demand to service any vehicle brand that comes through their doors. 

This shift from a brand-specific focus to a true multi-brand powerhouse came with significant challenges. The key to success? A fundamental change in how they prepare for every job - using ALLDATA Repair to access the same original manufacturer data as franchised dealers. Today, the workshop employs a team of seven skilled technicians who handle everything from routine servicing to complex diagnostics. 

Challenge: The Inevitable Demand for Multi-Brand Service 

The automotive landscape has changed. Customers no longer stay loyal to a single brand, and families often own a mix of vehicles. Autohaus Stumpf faced a steady stream of requests from loyal customers: 

The opportunity for growth was clear, but the obstacle was real. As Rouven Bauer recalls: “The big concern was that we couldn’t service non-core brands like a franchised dealer because we simply didn’t have access to the data. If we do a timing belt, what special tools do we need? What are the torque specs for the bolts? Where is the EGR valve even located if it’s broken?” 

Without access to OEM repair procedures, wiring diagrams, and service bulletins, complex repairs on unfamiliar brands were a gamble. The risk of misdiagnosis, incorrect repairs, or dissatisfied customers was simply too high. 

Solution: ALLDATA Repair Integrated into the Workflow 

The turning point came after conversations with other independent workshops who consistently recommended ALLDATA Repair. Autohaus Stumpf decided to take a free 14-day trial with a simple philosophy: see if it works. 

The impact was immediate and transformative. ALLDATA Repair became the central nervous system of their workshop for all non-core brand vehicles. Bauer’s team integrated it into their workflow at every stage: 

1. Accurate Pre-Repair Preparation and Quoting 

When a customer arrived with a Fiat motorhome showing a check engine light, the engine was running in limp mode. The team read out the fault code P0402 (EGR system) and turned to ALLDATA for clarification. 

Bauer recalls: “We entered the fault code into ALLDATA, and it showed that the vehicle actually had two EGR valves - a low-pressure and a high-pressure valve. What we saw when looking into the engine bay was only the low-pressure valve. But the actual fault was coming from the high-pressure valve. We only discovered that thanks to ALLDATA.” 

The OEM repair instructions then revealed the full scope of the job: removing the diesel particulate filter and several components, with around 8–9 hours of labour required. 

“Without ALLDATA, we would have simply replaced the visible low-pressure valve, and the light would have come back on. With the manufacturer data, we were able to diagnose the problem correctly and give the customer an honest quote.” 

2. Building Trust with OEM-Grade Service 

When a customer brought in their new Volkswagen T-Cross for its first service, it was crucial to complete the inspection exactly according to the manufacturer’s requirements to keep the warranty intact. 

Bauer explains the process: “My first step is always to check ALLDATA. I enter the vehicle details and request the official maintenance schedule. This tells me exactly what’s required - sometimes it’s just an oil change, but for the T-Cross the service also included a brake fluid change, headlight adjustment, and several system checks.” 

Having the precise checklist allowed the team to prepare all the parts, estimate the labour time correctly, and present the customer with a transparent, OEM-level service quote. Bauer continues: “The problem was perfectly solved with ALLDATA. You even get the original VW service plan, which greatly contributes to customer loyalty. When I explain the invoice and it includes that plan, it creates immense trust.” 

ALLDATA also revealed an open safety recall on the vehicle’s emergency call module - something the customer would normally expect only a VW dealer to identify and address. This not only strengthened the customer’s confidence in Autohaus Stumpf but also proved that an independent workshop could deliver true dealer-level service. 

3. Empowering Technicians and Removing Fear 

The biggest cultural shift was empowering technicians to work on any brand without hesitation. Bauer gave every mechanic access to ALLDATA. 

“Out of seven technicians, five thought we couldn’t do the change. But now, since everyone can look up exactly what needs to be done, the fear is completely gone. Why? Because it’s no different than repairing Opels for ten years - they also look up the instructions first.” 

From replacing a side mirror indicator to programming a Jaguar headlight, technicians now rely on original OEM procedures, torque specs, and wiring diagrams - turning once daunting repairs into routine tasks. 

Results: Expanded Revenue, Customer Trust, and a Future-Proof Business 

The results for Autohaus Stumpf are clear: 

For Bauer, the conclusion is clear: “I have to be completely honest: without ALLDATA, it would be absolutely impossible. Vehicles today are complex - you simply don’t stand a chance anymore without access to original manufacturer repair data. There is no way around ALLDATA if you want to work as a professional, independent workshop on all cars.” 

And about the cost: “What you save in time with ALLDATA already pays for it. You don’t need to call a friendly dealer around the corner anymore - these ten minutes are saved in just one minute with ALLDATA. That’s why it pays for itself.” 

While complex repair cases stand out, Bauer says the biggest impact is in everyday work. Removing trims or finding hidden components now takes minutes instead of hours, thanks to precise OEM steps.  

Even simple jobs like bulb or oil changes on unfamiliar brands are quicker and safer. With ALLDATA Repair, Autohaus Stumpf carries out routine maintenance and diagnostics with full warranty protection and transparency .  
 
“Our customers trust us because we can show we work with the same data as the manufacturer,” says Bauer. “That’s real professionalism.” 

Conclusion: The Non-Negotiable Tool for Modern Repairs 
 
Autohaus Stumpf’s journey from Opel/Mazda specialist to multi-brand expert is a blueprint for the modern workshop. The demand for servicing diverse brands is not a trend - it’s the new reality. 

The difference between thriving and surviving is preparation. By embedding ALLDATA Repair into their workflow - from the initial inquiry and quoting to the final repair and service record - Autohaus Stumpf doesn’t just guess. They know.