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· Registered
798 Posts
Discussion Starter · #1 · (Edited)
I've spent the last few days watching diy'ers on youtube and various other sources on how to "correctly" bleed the fluid from the clutch lines.

Fortunately I just bought myself a pressure bleeder and a bunch of Super Dot 4 Pentosin brake fluid and will be experimenting with various methods on how to eliminate all of the old fluid and air.

Unfortunately, for the individuals who prefer to reverse bleed their clutch, I will be unable to do any sort of comparison because I do not have the equipment. The majority of them used a simple oil can lubricator to pump the brake fluid up through the bleeder nipple and up into the reservoir. This to me doesn't seem as convenient as finding an appropriate method using a pressure bleeder. This way, only one tool is needed to do brakes&clutch. Plus I highly doubt using anything other than a tool specifically built and RECOMMENDED by BMW to flush brake fluid will yield better results...

My guess is to why there are so many variations in this maintenance procedure is because nobody reads the bently manual... It has some very specific instructions on doing this job. However I think it can be improved..

Let me explain. The bently manual says to pressure bleed the system normally with the slave cylinder on, close the bleed screw and operate the clutch 10 times. Next, the slave cylinder comes off and depressed using a special bmw tool (I saw somebody on youtube use his hands to do this) that you can get on bav auto. Finally, the system is then pressurized again and bled a second time with the bleed screw held facing up.

This method allows air to be expelled from the hydraulic piston inside of the slave cylinder but not the master cylinder. Now I am not an expert in the anatomy of the clutch mechanisms, but BMW had one of the cylinders completely closed as the bleed screw was open. I would just assume they would have included another step with an assistant operating the clutch during the final bleed.

I only say this because I was watching the 50s kid video and the instructions for bleeding the brakes per BMW says you must operate the brake pedal 5 times while the bleed screw is open w/ a pressure bleeder. This allowed air to escape from the master cylinder and flow out the bleed screw.

So this is how I plan to flush my clutch:

1) Replace fluid in reservoir with fresh fluid

2) Bleed the brakes:D

3) Remove slave cylinder from bell housing & duct tape push rod down

4) Pressurize bleeder & loosen bleed screw with screw being pointed up

5) Slowly operate clutch until fresh fluid runs

6) Tighten bleed screw & reinstall slave cylinder

7) Top off fluid

Any thoughts? Hopefully this will go down today but if not that will just allow me to get yalls input.


· Premium Member
5,137 Posts
I just open the bleeder, and wait until the fluid runs clear.

Close the bleeder, cycle the clutch a few times, repeat.

Since the latest car had black fluid when I bought it, I repeated the above
a number of times until it ran clear after cycling.


If the system goes dry, a few psi of air in the reservoir works. Sometimes it's a pain to get
a dry master or slave to bleed, but usually the air does it just fine.

The clutch is self- bleeding, as in, unlike the brake calipers, if there is some
air trapped in the system, it will eventually work its way out over time.


· Premium Member
2021 Lexus ES300h Premium
29,647 Posts
I wouldn't think or imply the Bentley manual is some sort of authority on BMW E46 stuff. They write books for Geo Prizm, Ford Ranger, Ford Taurus, BMW, etc. They're just the Walmart of instructions. They may be correct on some or even most things, but I've found them to be way off on many things E46. For me, there's one authority and it's BMW only. So if whatever you wrote jives with BMW, then it's the proper way. (TL;dr)
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