Type 1 Engine Half Moon Bolt (Starter Motor Bolt)

Starter motor mounting bolt, commonly known as the “half moon bolt”, used to secure the starter motor in position on aircooled VW engines. This bolt runs from the front (engine side) through the engine tinware and gearbox bellhousing, threading into a nut positioned behind the fan shroud.

Unlike a standard bolt, the half moon design features a shaped head that locks into place, preventing it from spinning during installation or removal. This is essential due to the limited access behind the fan shroud, allowing the starter motor to be securely fastened without needing to hold the bolt head.

The starter motor is responsible for turning the engine over during ignition. A secure mounting is critical to ensure correct alignment with the flywheel. A worn, incorrect, or missing bolt can lead to starter misalignment, noise, or even damage to the starter or flywheel teeth. This correct M10 x 100mm bolt ensures proper fitment and reliable operation.

This bolt is suitable for manual transmission models only and is not compatible with automatic vehicles. It is a direct replacement for the original part and is ideal for restorations or when replacing a missing or damaged fixing.

For a complete installation, you will also require the correct rear nut (N01101011A). It is recommended to inspect the starter motor bush (where applicable), wiring connections, and mounting surfaces when replacing the starter motor or hardware.

Fitment

Aircooled VW

• Beetle Saloon & Cabriolet 1949–1979
• T1 Split Bus 1950–1967
• T2 Bay Window 1968–1975
• T25 / T3 Transporter (Aircooled models) 1979–1983
• Karmann Ghia Coupe & Cabriolet 1955–1974
• Type 3 (Fastback, Squareback, Notchback) 1961–1973
• Trekker (Type 181) 1968–1983
• Buggy / Baja (Type 1 based) 1949–1979

Product Details

• Thread size: M10
• Length: 100mm
• Application: Starter motor mounting
• Note: Not suitable for automatic models