Hi all,

I cannot get my clutch to bleed on my 240D. I’ve bled the brakes, tried to reverse bleed with the RF caliper, tried vacuum from the clutch feed line with a bottle of brake fluid hooked to the slave nipple, and I’ve tried just leaving it for a week. Still nothing. Sometimes I can get a little resistance from the clutch pedal, sometimes none. Sometimes it will pull itself to the floor from halfway depressed. I’m at a loss here and my only thoughts left are that my master or slave cylinders are the issue. How can I diagnose the two? And I’ll welcome any other methods for bleeding. The only thing I haven’t tried is method #1 in the Haynes manual using a power bleeder.

Is it reasonable and possible to rebuild the cylinders for they’re faulty? I’d prefer to rebuild them than replace them.

Thanks, happy motoring

What brought you to the decision to bleed the clutch?

Rebuilding used to be standard procedure. You need a cylinder hone which is probably ~$15 and a seal kit. Air helps. You put a rag over the piston end and put air to where the line attaches. The rag catches the piston and spring.


You could use a pressure bleeder but regular old pump bleeding was common when these cars were new.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

I think a lot of us have had issues bleeding clutches on a W123. The method I always use is the oil can method. Reading what you wrote I'm not sure if you tried that method yet.




Simply get yourself one of these as well as some tubing to connect the can spout to the bleeder valve on the slave and fill the can up with brake fluid of course. You will be reverse bleeding the system from the slave and then fluid will travel through the clutch hydraulic system into the brake fluid reservoir so drain a bit out of the reservoir first.

If you notice the slave valve leaking, pull it all the way out and wrap some Teflon tape around the threads, making sure to keep the small hole in the valve clear and free of the tape.

Put it back in and hook up your oil can and keep pumping. I usually do a bit of pumping, close off the valve and take a little break and then go a few more rounds. It has worked for me and many others.

Like I said above, I can't tell if you tried that method yet but this method has never failed me.

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My clutch slowly getting lighter then not disengaging. Pumping a few times then shifting worked, then it stopped altogether.

kw:

If there were: 1) no obvious fluid leaks, and 2) the level in the reservoir has been kept above the clutch feed port, then a hydraulic problem is low on the list. Mechanical faults are higher on the list. Slave pushrod has punctured the release lever; clutch diaphragm spring has failed; release lever has cracked & bent. Pumping the clutch pedal served to increase the travel of the throwout bearing somewhat.

What if I run the clutch dry? I only just realized there’s a second chamber for the clutch.

At this point I just want to make 100% sure the clutch is properly bled before I proceed. I think I’ll try the power bleeder/ oil can next.

Thanks for everyone’s help

I am not sure if you replaced the master cylinder or not but some of the replacements have the rod just slightly too long which causes it to be pushed in slightly and wont bleed. I went thru this on a 240D and ended up having to disconnect it from the pedal, bleed it with the can method above, then reattached the rod.

I can second this, I have run into this issue before as well. Definitely give this a shot.

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Reading the OP's statement first would preclude making the statements of the other two posters.
The MC has not been replaced.

Well your master cylinder or your slave cylinder has failed, and bleeding the clutch will only help you after you replace the failed part.


Typically when the MC fails, it leaks brake fluid, so you can see the leak under the dash in the driver's foot well. Sometimes it will fail internally and then no visible leak.



In your shoes, if you can't spot any leaks, I'd replace the MC first, and if that doesn't resolve the issue, then replace the slave.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Thanks for all your inputs. I'm banking on the MC being the problem too. I have started to run out of patience so today I'm bringing it to my local Mercedes service guy.

If I could pinpoint what the problem was I'd tackle it but I'm not prepared or willing to start throwing money and parts at something till it sticks. Hopefully the shop can tell me definitively what's wrong.

Also for future note, the oil can I got to try and reverse bleed did not work. Either the fluid melted the seals or its the type of can, but the fluid it pumps out is full of micro bubbles so that wasn't going to work. I could fabricobble some abomination of a pressure bleeder but as I said, my patience is wearing thin. It'll be nice to have some free space in the shop for a while...

This is my experience, yours may be different. I tried to bleed my 190D from underneath the car, hooking a line from brake to the slave nipple. The slave cyl would not take any fluid. I replaced it and found the nipple area was clogged with debris. I decided to change the master as well. If you do the work yourself then changing both cylinders out is not that expensive. Good luck.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

Barely press the clutch pedal, right at the threshold of creating pressure in the clutch. Move it slowly in/out of that range many times. That will allow air bubbles to escape into the reservoir.