After a curious experience with clutch bleeding, and after doing a search of the archives for a technique for bleeding the clutch system, I developed the following process which seems to have worked and which can a one person operation. First some background…

Background
1. Betty had been sitting idle with the engine bay completely bare for refinishing for about 10 months. During this time the entire clutch hydraulics system was out, dismantled and inspected. I found that both the master and slave cylinders appeared to have been rebuilt by the PO. When Betty was running previously the clutch system had worked well with no leaks or shifting issues.
2. In the process of putting everything back together I installed a new clutch hose. I then bled the system using the bleed nipple only and I had all the air out in a couple of minutes. The slave piston travel was about 7/8”, which IIRC is about right.
3. I then discovered that I had managed to get the gas line on the wrong side of the clutch hard line, so I removed the clutch hard line, with all the fluid draining out, and moved the gas line adjacent to the frame, where it belonged.
4. I then reconnected the clutch lines, filled the reservoir and then spent the next hour trying to bleed the system via the nipple. I even waited a couple of hours and tried again for another ½ hour before giving up and doing an BB archive search.
5. Not find anything that clearly solved my problem, I sat down, scratched my head for a bit and then wrote down the following set of steps, which thankfully worked.

Process
1. Start with slave cylinder not bolted to the clutch housing, but otherwise with the system completely assembled.
2. Fill reservoir.
3. Loosen bleed nipple until fluid runs out.
4. Close nipple.
5. Note fluid level in reservoir. If less than ½ full, top up to ½ way point.
6. Gently push the rod into the slave cylinder, watching (and listening) for bubbles in the reservoir and/or potential overflow of fluid.
7. With rod fully pushed in, top up reservoir to ¾ full point.
8. Withdraw rod and left the slave piston return to its normal extended position. Watch the reservoir level and ensure it doesn’t go dry (unlikely).
9. Push rod all the way in again and again watch/listen for bubbles. Repeat the process, starting at step 6, until there are few bubbles.
10. Mount the slave cylinder and then bleed in normal fashion.

Cheers,
--
Barry -- 1967 122S 'Betty'

When I read your Subject, I thought you were going to ask for a method. I have done this reverse bleed technique on my manual Trani Chevy Pickup. I went through way too much fluid and got nowhere one evening until I too scratched my head and came up with the ass-backwards approach. I guess you can get a much larger push when the Slave is disconnected from the Trani. I have also used this method when having a hard time bleeding brakes on my Jeep.

Not enough pump of the pedal travel to get the air up,around and down these SS brake lines I installed.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

What you are doing here is equivalent to bench-bleeding a brake master cylinder. Between steps 9 and 10 it would be a good idea to suction out all the old bubbly fluid in the reservoir and replace it with fresh, otherwise it sounds like it should work nicely.

If I remember correctly, the official procedure for bleeding the clutch hydraulics on a Mercedes is considerably more involved. You are supposed to connect the bleeder screws of the clutch slave and the left front caliper with a jumper hose, open both bleeders, and pump the brake pedal to force fresh fluid through in the reverse direction. If you try this, watch the level in the clutch reservoir, as it will rise, and you don't want to overflow it, especially with a newly painted engine compartment. My concern with this method is that it is difficult to get a good seal on the jumper hose, and even if you do, it is still possible for air to get in through the threads of the bleeder screws. When I did mine, (78 240D) I used a combination of gravity bleeding and pedal pumping, and eventually got it to work satisfactorily.