Can't bleed the !@#$ing clutch - PeachParts Mercedes-Benz Forum

JEBalles · #1 06-06-2009, 07:12 PM

I've probably had worse luck than everyone with this manual transmission. So much for being more reliable and easier to maintain. This is the first time I actually wish I had an automatic. My first transmission's output shaft and flange splines were stripped, then the second one I bought had worn synchro rings and my third one's slave cylinder just exploded. I put another used one on, but now I can't bleed it. I hook up a hose from the brake caliper to the slave and open both screws and go nuts on the brake pedal, just like stevo recommends. This has worked for the past two times. This slave has a new bleed screw, thinking the old one might be blocked by something. When I pump the brakes, it's like nothing is getting into the clutch system, pressure builds up in the hose until it pops off the slave. WTF!?

Stevo · #2 06-06-2009, 10:56 PM

could be the used slave is NG, if the nipple is not clogged.

JEBalles · #3 06-06-2009, 11:12 PM

What's NG? This slave is the one that was on the original transmission, so I know it did work, but I've never bled it. I also pushed the clutch pedal when the slave wasn't bolted to the housing during the first swap, and it pushed out the rod, but I just pushed it back in, I didn't think that would make a difference...

Stevo · #4 06-07-2009, 09:51 AM

NG= no good, which is still my guess. It sounds like your bleeding technique is correct, pumping like mad then closing the bleeders is the way that works with our systems. I would buy a new slave.

JEBalles · #5 06-07-2009, 09:52 AM

I'm not really sure I understand. Where does the air go? Do I open the bleed screw when I push the rod back?

JEBalles · #6 06-07-2009, 09:57 AM

Why would this slave be no good? it was working well before, is the bleed port just clogged with something? I'm operating on a negative budget here, so I can't just go buying new slave cylinders willy-nilly.

Stevo · #7 06-07-2009, 10:37 AM

Quote:

Originally Posted by JEBalles

When I pump the brakes, it's like nothing is getting into the clutch system, pressure builds up in the hose until it pops off the slave. WTF!?

The clutch pedal is not down to the floor while your pumping the brakes right? just checking. Are you sure the hose is attaching securely to the bleeders? (hose clamps)

Oracle12345 · #8 06-07-2009, 10:41 AM

bleeding slave cylinder is like doing the brakes. I recently replaced the slave on the geo which has a hydraulic clutch. I know not the same car but still a hydraulic clutch. I hit the clutch pedal once or twice, loosened the the bleeder screw then used a handheld vacuum pump to get all the air out.

JEBalles · #9 06-07-2009, 11:30 AM

Well, I've never bled the brakes before and I have bled the clutch system before. Unfortunately, I do not have a vacuum pump, does anyone have one I could maybe borrow? I know I should buy one, but I just haven't the money. The clutch pedal is not down when pumping the brakes, the hose is held on by hose clamps and by my hands while someone else pumps the brakes. What I just did was push the clutch pedal, open close screw, up and down on the pedal, etc. while still bolted to the transmission about 40 times. No fluid ever came out of the screw, but the pedal became slightly firmer (it came up by itself by the end) but fluid level looked about the same, I could also see the rubber hose connecting the pipes pulse whenever the pedal was pushed.

Oracle12345 · #10 06-07-2009, 11:52 AM

Quote:

Originally Posted by JEBalles

Well, I've never bled the brakes before and I have bled the clutch system before. Unfortunately, I do not have a vacuum pump, does anyone have one I could maybe borrow? I know I should buy one, but I just haven't the money. The clutch pedal is not down when pumping the brakes, the hose is held on by hose clamps and by my hands while someone else pumps the brakes. What I just did was push the clutch pedal, open close screw, up and down on the pedal, etc. while still bolted to the transmission about 40 times. No fluid ever came out of the screw, but the pedal became slightly firmer (it came up by itself by the end) but fluid level looked about the same, I could also see the rubber hose connecting the pipes pulse whenever the pedal was pushed.

you can buy a hand held vacuum pump at autozone $29

JEBalles · #11 06-07-2009, 12:17 PM

Alright, let me get this alternative method straight:

1) Unbolt slave from trasmission
2) Close bleed screw and keep closed
3) Depress clutch pedal and keep depressed
4) Holding slave upright (push rod pointed up) push the rod back into the cylinder
5) Pull pedal back up
6) Repeat until pedal feels firm

Now is this right? Now I can't figure out how this fills the system with fluid if it pushes air back up to the reservoir. I don't really care how, though, as long as it works.

JEBalles · #12 06-07-2009, 06:51 PM

So, does anyone have any idea why the clutch might not be able to be bled? I'd hate to spent 75 bucks on a new slave to find out it's something else.

JEBalles · #13 06-07-2009, 07:44 PM

UPDATE: The bleed port is not clogged! After going through standard bleeding procedure as described in post 10 (I have not yet tried the alternative method), in a fit of frustration and confusion, I just opened the bleed screw and just went violently nuts on the clutch pedal. Fluid came out of the screw! I will continue this and hopefully it will work.

hockeyboysomers · #14 06-07-2009, 09:34 PM

Lots of people have trouble bleeding hydraulic systems, you are not the first. Imagine how long the brake lines are on a airplane. This is how we did it on an aircraft. This system works on brakes or hyd clutches.Unless you have a vacuum pump it is a two person job. Have your assistant pump on the pedal about 20 times. This forces fluid into the line. After twenty pumps, have them hold the pedal to the floor, do not release the pedal. Now open up the port on the slave cylinder. There should be a small escape of air (psst). Quickly close the port. Now your assistant can release the pedal. Repeat this process a number of times (10). Each time you should get more air and fluid when you open the port (pssst), (pssssst), (ect). Eventually you will only have fluid comming out of the port, no air. Check several times that the reservior is full. If the reservior goes empty, air will be introduced into the line and you will have to start over again. You will also have to start over if your assistant doesn't keep the pedal down when you open the port. Once again air will be sucked up into the line. This method doesn't cost anything, and should only take about twenty minutes. It is fool proof and should work as long as there are not other problems in the system. Good luck, and let us know how it works out. Dave

JEBalles · #15 06-07-2009, 10:27 PM

Yep, that's exactly what we did, and it worked. This is actually what my pop originally recommended, but the last two times, I used FSM and that worked fine, although it's messy. I'm using this method from now on. I'm still curious why the FSM method didn't work, though...