211-501-221A VW Bus 46mm Rear Axle Nut - 1964-1979 Type 2

Rear Axle Nut (46mm "Big Nut") – 211-501-221A

The 211-501-221A is the essential fastener for late-model split-window and all bay-window Buses. Because the Bus is significantly heavier than the Beetle, Volkswagen upgraded the axle nut size from 36mm to 46mm starting in 1964 to increase the clamping surface area. This nut is responsible for holding the entire rear rotating assembly together; if it is under-torqued, the splines on the brake drum can be stripped, leading to a total loss of drive.

This part is also a direct fit for later water-cooled models, including the Vanagon and Syncro. When performing any rear brake or wheel bearing service, it is highly recommended to replace the nut if the slots are rounded or if the threads show any signs of stretching.

Detailed Vehicle Compatibility

VW Bus (Type 2 / Transporter):

• 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979

VW Vanagon (Type 25):

• 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991

Product Highlights & Features

• Heavy-Duty Hex Size: Requires a 46mm (or 1-13/16") socket, typically in a 3/4" drive, to achieve the necessary leverage for removal and installation.

• Precision Threads: M30 x 1.5 thread pitch designed for a perfect interface with the rear stub axle.

• Corrosion Resistance: Typically finished with zinc-plating or phosphate to resist seizing and rust in high-moisture environments.

Technical Specifications

• Part Number: 211-501-221A

• Socket Size: 46mm

• Thread Size: M30 x 1.5

• Type: Slotted Castle Nut

Installation & Maintenance Tips

• Torque is Critical: You must use a 3/4" drive torque wrench or a torque multiplier tool to reach the required 253 ft-lbs. Standard 1/2" wrenches usually do not reach this range.

• Always Use a New Cotter Pin: Never reuse an old cotter pin. Metal fatigue from bending the legs can cause the pin to snap, allowing the nut to spin.

• The "One-Turn" Rule: If you reach 253 ft-lbs and the slots do not align with the hole in the axle, always tighten further to the next available slot. Never loosen the nut to align the pin hole.

211501221A