Mercedes-Benz W198 300SL Gullwing
Description
As the UK’s leading W198 (Gullwing & Roadster) specialist, we undertake a wide range of work on these models, from comprehensive ‘nut and bolt’ restorations to general maintenance and servicing.
This particular Mercedes-Benz 300SL Gullwing came to us at very short notice after being accepted into the prestigious 2025 Mille Miglia. Preparing a vehicle for an endurance rally always demands time and attention, and the 1,000-mile Mille Miglia is a true endurance event that requires a ‘no corners cut’ approach.
The initial report on the car highlighted a significant gearbox oil leak, poor running and the need for a full service. As with all vehicles, before allocating budget and spend, we carried out one of our detailed mechanical inspections. This allows us to review and prioritise defects based on safety as a benchmark, alongside customer preference.
With the gearbox requiring a full reseal, it was removed from the vehicle. After complete disassembly, all gears and components were carefully inspected for wear or damage. It is best practice to renew bearings at this stage, and our team also completed several small but essential, non-compromising modifications to ensure smooth operation and long-term reliability. While disassembled, the bell housing was vapour blasted, refinished in the correct black shade and all fixings zinc-coated to factory specification.
The team also worked through a number of other smaller defects, including renewing all of the perished rear axle seals, which were leaking, and replacing the rear axle bushes, which had begun to deteriorate. Preventive maintenance on classic vehicles, especially complex 300SLs, is the best way to avoid breakdowns or issues during endurance events.
Before the car’s first road test, it was given a comprehensive service, with all oils renewed and upgraded to the latest specification products. The ignition and fuelling systems were carefully checked and adjusted to ensure smooth running. The early Bosch direct injection pumps fitted to W198 300SLs were revolutionary in their time but require precise maintenance and setup to keep them performing at their best.
Suspension geometry was also checked to guarantee the desired handling characteristics for the car’s intended use. Once complete, the road test allowed the team to review the car for any final remarks or drivability concerns before delivery to the event.
