[PA66400]

I replaced my 335 CDV this weekend with a $10 direct-fit BMW CDV from the M3 (purchased online from ECS tuning, BMW part 21522283914). The M3 CDV has no restrictor in it - a huge difference from the nearly pinhole orifice in the standard 335 CDV. For those who have a six speed manual, I find the driveability difference extraordinary. I highly recommend this inexpensive modification. I now no longer have to delay stepping on the gas until my clutch is fully engaged. The car accelerates faster and more smoothly, as a result. It drives like a "normal" manual transmission and is not an embarrasment. I have no idea why the "ultimate driving machine" engineers allowed the 335 CDV into production, as it significantly detracts from an otherwise great drivetrain.

The CDV removal and replacement is very easy, as noted in earlier posts and DIY on this forum. BUT, it took me several hours to figure out the quirky technique needed to bleed the clutch slave cylinder - contrary to other posts here, you MUST bleed after replacing the CDV, as you can't avoid trapping air in the clutch line when opening the line for the CDV replacement.

After hours of bleeding the clutch hydraulic line and getting only air and a limp pedal, I realized that the only way to bleed it is to have the braking master cylinder filled to the absolute brim, as the clutch is partitioned from the master cyliner and draws fluid from only the top few mm's; the clutch master cylinder can easily run dry while the rest of the master cylinder appears full. Keep this in mind when bleeding your clutch using any technique (pressure bleeding, pedal bleeding or suction bleeding), as no technique will work unless you keep the master cylidner constantly full to the brim! The clutch partition will run dry in 4 pedal strokes, otherwise. Hope this helps, if you do the CDV!