# Brake/Clutch Bleeding: Pressure vs. Vacuum



## mototodo (Oct 3, 2003)

I have been contemplating the CDV delete procedure on my 2001 530i. It must be exorcised. I have read write-ups that call for pressurizing the hydraulic system to bleed the clutch. This would require me to purchase (or fabricate) a bleeder pressurizing tank. I have a MityVac vacuum tool and I am wondering if there is a reason the system must be pressurized, rather than vacuuming the air out of the lines.

Todd


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## Ågent99 (Jan 7, 2002)

Todd,

Dave can actually handle the CDV, the RE SSK and tranny mounts, and treat you to a might fine imported beer!  Check out his site: www.zeckhausen.com

You DO NOT need to pressurize anything. If you could, it would be nice but in no way is this necessary.

The nice thing about the clutch is that it will "self-bleed" itself of air. If your clutch feels mushy when you are all done, just keep pumping it and it will firm up. This happend to my car and it came back after pumping it many times and a drive around the block.

However, that said, you can still bleed the clutch and use your MityVac to suck the fluid away. Just keep an eye on the very back reservoir on the master cylinder. Bleeding the clutch is very quick as the line is very short.

However, I've found that most of the air introduced into the clear tube comes from the bleeder valve leaking air and not your clutch!

If you don't lose much fluid during the CDV work, odds are good you won't have to touch the bleeder valve on the clutch. Just top up the fluid at the m/c and go for a drive.

Doing brakes is another story but the clutch is quite easy when it comes to flushing/bleeding.

Chris


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