B&M 420 Mega Blower Rebuild Kit

Included is two precision 5205 hi-speed ball bearings for the front of the supercharger, two rear caged roller needle bearings and four rotor shaft seals. Rotor shaft seals are a durable double lip seal that measure 1.755" O.D. x .250" thick with a 1.250" shaft.

Also included is a gasket set which includes a base gasket, front cover gasket, rear bearing cover gasket and four bearing plate to blower case gaskets .015" thick so rotor to bearing plate clearance can be adjusted if needed.

Last but not least a sealed hi-speed precision ball bearing for the blower snout with a new Spirolox retaining ring and a Buna rubber blower snout seal that measures 2.075" O.D. x .315" thick with a 1.250" blower snout driveshaft. Now one of the most important parts of the rebuild are two new heat treated grade eight gear bolts and two heat treated steel washers to hold the gears in place when the bolts are torqued. These washers in stock form are prone to cracking and allowing the bolt to come loose that holds the gear allowing the rotors to go out of time and you know the rest of the story, it gets ugly.