Author Topic: Bleeding clutch master cylinder  (Read 2704 times)

badali

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Bleeding clutch master cylinder
« on: December 08, 2022, 16:15:02 »
I just put the transmission back in my 220Sb.  I replaced the hose going to the slave cylinder and now have air in the system.  The clutch pedal goes to the floor and will not return unless I pull it up.  How do I get the air out and could there be something else wrong that I did not know about or caused?  I gravity bled the slave cylinder.  Also, while I had the hose off the fluid mostly drained out.
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

rwmastel

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Re: Bleeding clutch master cylinder
« Reply #1 on: December 08, 2022, 19:47:06 »
Rodd

Did you search the forum before asking?
2017 C43 AMG
2006 Wrangler Rubicon
1980 450SL
1966 230SL

badali

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Re: Bleeding clutch master cylinder
« Reply #2 on: December 09, 2022, 11:08:11 »
I still haven't gotten the air out.  I'm not sure what to do at this point.  Any help would be appreciated.
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

Cees Klumper

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Re: Bleeding clutch master cylinder
« Reply #3 on: December 09, 2022, 13:24:43 »
Following with interest since I am facing the same issue on my '72 Lancia Fulvia. Rebuilt the master cylinder and all 4 calipers, bled the system but pedal going to the floor.
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
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BobH

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Re: Bleeding clutch master cylinder
« Reply #4 on: December 09, 2022, 15:32:11 »
There's a brief description in the Tech Manual, i assume the process must be similar for other cars, otherwise plenty of UTube videos on the subject

https://www.sl113.org/wiki/Clutch/Start
February 1965 230SL Automatic
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Charles 230SL

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Re: Bleeding clutch master cylinder
« Reply #5 on: December 09, 2022, 15:41:39 »
hello Brad, I replaced the hose going to the slave cylinder on my 230SL a few years back and I found the easiest way to get air out of the system was to first gravity bleed the slave cylinder (which you did), close the bleed valve, remove the clutch slave spring and then using the clutch lever, apply pressure to the slave while "jiggling" the clutch lever to shake loose any air bubbles.

Andy Burns describes how he did it here: https://www.sl113.org/forums/index.php?topic=18284.msg156021#msg156021

badali

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Re: Bleeding clutch master cylinder
« Reply #6 on: December 09, 2022, 16:13:57 »
I will try it and get back to let you know if it works for me.  Thanks very much!
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

450sl

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Re: Bleeding clutch master cylinder
« Reply #7 on: December 09, 2022, 16:53:44 »
In remembrance of our late great fellow member  Naj  ... and all Credits and Copyrights to him  ;


Fill the resevoir 2/3 to 3/4 full.Leave cap off.
Get under the car and work the piston/rod back into the cylinder.
You will hear the air bubbling out of the resevoir and the piston will come out again sucking fluid with it. A few strokes and no more bubbling.
Now try the pedal. Top up resevoir and fit cap.


mark

Pinder

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Re: Bleeding clutch master cylinder
« Reply #8 on: December 09, 2022, 18:27:53 »
The last post about having to get under the car and forcefully pressing the rod etc is what did it on my cat when I changed the cylinder (with a newone) plus a new hose. It took a lot of tries to make it finally work but now its been about 5 years and its been perfect.
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

badali

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Re: Bleeding clutch master cylinder
« Reply #9 on: December 09, 2022, 20:05:09 »
I got a little more return on the pedal but it stops short of halfway on the return instead of at the floor.  I tried both methods here...  I have to stop for the day...
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

ja17

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Re: Bleeding clutch master cylinder
« Reply #10 on: December 10, 2022, 03:03:49 »
Connect a bleeder tube from the front brake caliper bleeder to the clutch
slave cylinder bleeder. Remove the cap on the clutch fluid tank. Open both bleeders and pump the brakes a couple of times. Close both bleeders, finished.
Joe Alexander
Blacklick, Ohio
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badali

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Re: Bleeding clutch master cylinder
« Reply #11 on: December 14, 2022, 22:45:20 »
I tried everything so I bought this clutch master cylinder from Niemöller,  I may have found one of the last ones in the world.  They are now out of stock,,,  It is identical to the one on the car and I had a heck of a time finding it since it is discontinued.

Niemöller is easy to deal with.  They sent an email saying they shipped it Monday and I received it in 48 hours (Germany to Pa)
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

badali

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Re: Bleeding clutch master cylinder
« Reply #12 on: December 23, 2022, 16:39:27 »
I found that the pin on the clutch slave cylinder may be part of my problem along with the slave cylinder sticking.  What length should the rod be?  The short rod was the one on the current cylinder and it is extended out as far as it will go.  The long one is so long that it will not disengage when the pedal is up.  I'm going to install the new slave cylinder.  Which pin is correct and what length should it be?
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

badali

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Re: Bleeding clutch master cylinder
« Reply #13 on: December 23, 2022, 18:43:15 »
New parts are installed.  I put the longer rod in.  Looking at the book I think I have the 1rst version by all I have read.  The longer rod is 49mm all the way in.  That is as short as I can get it.  The other rod is actually 43mm (the one that was on it).  The car always did grind a little when shifting before all the work was done so I'm hoping this will help solve this issue. 

The clutch pedal does go down and comes back up but there is still a little air in the system.  I will get a helper to finish that another day.

If someone could verify that I have the correct length rod this will help.

My Vin is 111.012-10-031926
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic

badali

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Re: Bleeding clutch master cylinder
« Reply #14 on: December 30, 2022, 22:03:47 »
I finally got the clutch bled today.  I replaced the slave cylinder, the hose and the clutch master cylinder.  I used the 49 mm rod on the slave cylinder and it worked to engage the gears properly.  I used a large syringe and forced the fluid through from the bleeder on the slave cylinder.  It held more than enough for the complete system.

Now I'm back to the reason I started this with the gear shift linkage.  After I get the rest of the mounts back in I can get it on the floor and adjust everything.
Brad

1961 220 Sb
1966 230 SL
2019 E 450 4 Matic
2022 GLC 300 4 Matic