Bleeding clutch system. Am I even making progress?

[marsgorski]

I recently replaced both master and slave clutch cylinders, the only thing left for me to do is to bleed the system. I have no prior experience doing this and the information I've seen online is unclear about the correct method. Finally, I opted to try it this way.

Before trying I noticed that when I depressed the clutch pedal, it would not return. After trying to bleed the system, the pedal does return to the original position (it still feels very spongy, like there is not enough pressure pushing back against my foot. It won't let me go into first gear.) Is this a signal that I'm doing things correctly and need to continue trying the same procedure?

Anyone with experience bleeding the clutch (preferrably on an E30 or similar BMW) with advice about the best way to do it? I'm tempted to also try this next.

[ELVA164]

If you bench bled the slave cylinder, the rest of the system is self-bleeding. Slowly pumping the pedal should be able to remove the rest of the air.

[earthwormjim]

Unless you bench bled the slave, or have a pressure bleeder, you're going to have to pump for hours.

[superj]

and than you will have one Arnold schwartzenhanrnspdojfggar leg and one chicken leg

[sienayr]

You can also loosen the nuts and pump the slave in situ with you hand, this equates bench bleeding. Pushes the air up and out of the system, the way it wants to go.

[marsgorski]

Thanks for your responses. Sounds like bench bleeding is the way to go. Just to make sure, by bench bleeding you mean the procedure followed in this video, correct?

[sienayr]

Might as well try what I suggested before you pull it all the way off. It worked well for me.

[richardodn]

People have such convoluted methods of doing this, but it's really easy. First of all do you have a helper? It makes the job easier, but you can still do it by yourself.

Tools needed
Catch bottle for fluid - this style https://www.amazon.com/Genesis-Techn.../dp/B000W7F2GI The one linked is overpriced. The desirable features are the metal cable for hanging it and the extra nipple to connect the hose back to when you're done.
Wrench for bleed screw.
A pressure bleeder is a nice tool to have but not necessary.
DOT4 brake fluid

1. Pour a little fluid in the catch bottle. Just enough to cover the tube that runs to the bottom. This allows it to act as a valve.
2. Connect the pressure bleeder to the reservoir if you have one. Have about a pint of fluid in the bleeder. Otherwise just make sure to keep the reservoir full as you go through the process.

If you have a helper, they're going to pump the clutch pedal while you open and close the bleeder screw. Open->pedal down->close->pedal up. Repeat this until no or very few bubbles come out. Keep an eye on the reservoir level during this process. If you have one, the pressure bleeder should keep it full.

If you don't have a helper, just barely crack the bleed screw. Pump the pedal. Slow down pedal, then fast up. Eventually the pedal will start to stiffen up. Go a few more pumps after that. Close the bleed screw and remove the catch bottle and pressure bleeder.

You may not have all the air out of the system, but that doesn't matter. As long as you can release the clutch, it's good enough. The system on its own will finish the process over the next couple days.

[superj]

that's the main thing, the system will clean itself up once you get the main part done. no one seems to remember that but it does.

don't get all hung up on doing this. its very easy.

[marsgorski]

Might as well try what I suggested before you pull it all the way off. It worked well for me.

I tried your suggestion but it was a little difficult to maneuver with the slave cylinder in place. So I removed the cylinder.

I opened the bleeder, depressed the piston, tightened the bleeder, released the piston...repeat. I did this about 7-10 times. The last couple of times I noticed that no brake fluid came out. I installed the slave cylinder, went to look at the clutch pedal and to my disappointment I noticed that it stuck to the floor when depressing it.

I want to pause here for a question: When installing the slave cylinder back on, is it important whether the bleeder valve is open or closed? Mine was closed.

I was following the second video linked in my original post. At the end of it the guy suggests that if the pedal sticks to the floor after trying this bleeding process, then one should depress the clutch pedal and repeat the bleeding procedure with the pedal in the depressed position. Life got in the way so I wasn't able to try this but it seems natural now for this to be my next attempt. I don't know when that will be, but in the meantime if anybody has any insight into what could have gone wrong please share your thoughts. I will highly appreciate it.

Edit: Reading on other posts, it seems that when doing the bleeding position it is important that the bleeder valve is pointing up. I don't think that was the case during my attempt, so that could also be the problem.

[earthwormjim]

Just buy a pressure bleeder; pressurizing the system makes this a breeze. I use the Motive one: https://www.amazon.com/Motive-Produc.../dp/B0002KM5L0

It's handy for doing your brakes too.

[ELVA164]

What do you mean you bled until no fluid came out? It sounds like you just squirted all the fluid out of the cylinder... Bleeding should continue until only fluid and no air comes out. Keep refilling with fluid as you do this.

When bleeding anything, the bleeder should be at its highest possible point.

[marsgorski]

I've tried bench bleeding again, this time I made sure the the nipple was at the highest point. It did not work. I tried the procedure in the link in my last post, as well as asking a friend to pump the pedal for me 5-7 times he left the pedal depressed, I opened the valve (I noticed some pressurized our flowing out, but no fluid!) pushed the rod in, closed the valve, let the rod return. Then he would pump the pedal again, and I could feel the pressure pushing the rod out even further with each pump, which was encouraging. I also tried richardodn's method without the power bleeder. During all of these I noticed that little to no fluid came out after repeated attempts, only pressurized air. There was fluid in the reservoir well above the minimum line, and the level never went down. I did the above procedures with the cap on the reservoir. I'm kinda baffled and disappointed, I was hoping this would work.

I didn't want to buy an expensive pressure bleeder that I will probably won't use much, but I guess that's what I should do at this point. Any thoughts?

I've seen many online using the Motive pressure bleeder that earthwormjim mentioned above. Advance auto parts loans this vacuum pump for bleeding the breaks. Should that work just as well as the pressure bleeder?

[ELVA164]

The clutch system isn't very large or complex. Sounds like something isn't sealed properly or the reservoir was sucking air. As mentioned, the system self-bleeds after a while if everything else is correct.

[marsgorski]

It finally worked! Today I tried using a vacuum pump used for bleeding breaks. It didn't work. Weird thing is I could not draw any fluid with the pump attached to the bleeding screw, only air. (Yes, there was fluid in the reservoir. Tried it both with the clutch pedal depressed and released. That didn't make a difference).

I was about to give up when I tried the first method once again. I extracted almost all of the fluid from the reservoir and used the oiler can to pump the fluid from the bleeding screw. This time I was much more careful about keeping it airtight and I think that was the problem the first time I tried (too impatient).

It required a bit of patience but after a little while I saw the lever in the reservoir increasing and eventually reaching the "MIN" mark. After that I closed the bleed screw and topped off the reservoir.