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  #1  
Old 07-08-2014, 10:50 PM
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Bleeding a clutch via a brake caliper

Mercedes 190e 2.3 16v is giving me some issues with clutch pedal feel ,I came across one very clever idea installing a clear line from the passenger side caliper bleeder to the slave cylinder bleeder which will make the brake system reasponsible for pushing air out of the clutch system,This sounds very sound advise in that both borrow the same reservior .In all my searching for my main issue it was finally realized that my main problem as simple a reservior line to the clutch that was lose allowing air into the system ,well a long line of items were fixed in this process and most of it was found on this site ,thanks to peachparts past and present members a real forum of members who spend time for others in need.

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  #2  
Old 07-09-2014, 03:09 AM
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Did you actually try this trick?

I can see how it might work but old bleed nipples in wobbly calliper casting holes would probably leak too wouldn't they?

There is a down side (although I can imagine after trying to bleed a clutch on a W201 for a while most people won't care!) => doing this with dirty fluid in the clutch line of course means that the muck gets pushed back up into the reservoir.

Admittedly this is also a problem with reverse bleeding from the nipple up into the reservoir too - so to start with a drain and a power bleed downwards reduces the chances of muck ending up at the top of the system - and there's also the vague chance the downwards power bleed will work (in your dreams!)
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

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  #3  
Old 07-09-2014, 06:28 AM
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In the early seventies, using a line from a brake cylinder to slave cylinder was the procedure in the manual for some truck or another. If you can fit a line on it well, preferably a clear line, and you keep the reservoir full it will get the job done. It's not my method of choice, but it will work.

I don't know about 201 cars but every 123 or 124 car I've ever bled was easily accomplished by using the two person method, then let it set overnight to allow any remaining bubbles to rise.
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  #4  
Old 07-09-2014, 11:44 AM
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The dream is a good stiff pedal ,the nightmare is here already.The thread which I found here on PP described a complete bleeding of the system (brake ,clutch) Stretch with nice new clean fluid ,I believe it was a 240d manual car in which he located a line issue at the brake reservior and made an effort to take the system down of fluid prescribed by his local mechanic shop.The thread ,which was started back in 2005 , was the missing link to my no luck bleeding issue ,a lose line from the reservior (not leaking,hard to believe) was allowing air bubble into the system anytime you used the clutch ,the line HAS a woven fabric exterior which runs from the reservior to the master cylinder in the car.Hope this lesson I learned can save some time and money to others ,a new line installed here is were I would begin a mysterious clutch problem .The 29 YR OLD line is a bi$^& to get too inside the car(took the DR seat out to get under the dash )but in the end you will be a much happier fellow for it.
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  #5  
Old 07-10-2014, 10:22 AM
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A few years ago the clutch began to drag on my '88 190E 2.6, and I suspected the slave cylinder was bad, and I was right, but the failure mode was really surprising. The pushrod was worn and mushroomed over on the end. I've religiously changed brake fluid every two years, and the inside of the slave was perfect. I bought a new slave from Peach, which was only about 40 bucks and the cylinder casting had the same cast-in number as the original.

The clutch is easy to bleed during a fluid flush, but I was concerned how to fill it when empty. It was in the Haynes 190 manual that I read about this procedure to fill the clutch system from the brake caliper. Prior to doing the slave change I flushed the brake system, so it was full of fresh fluid.

There was a little fluid seepage from the caliper and slave bleeders, but since the fluid pressure is zero or postive as you depress the brake pedal, air won't get into the system, or if it does, it will migrate up. You only need to open the slave bleedeer about half a turn.

I gave the brake pedal about 10-12 pumps with a helper running the bleed valve, then tighten the slave valve and the clutch felt normal. To finish the job I bled the caliper a few more pumps and was done.

The procedure worked like a charm!

When flushing the brakes you have to be very careful to avoid draining the rear reservoir. You can really only see the level from the from the inside (engine side) of the reservoir at the very rear of the reservoir, and when you fill the reservoir, it's best to wiggle it side to side to be sure fluid spills over the baffle to fill the rear, which you can then visually check as above.

Duke
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  #6  
Old 07-10-2014, 11:01 AM
GemstoneGlass
 
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easy method, one person

Connect a long clear tube to the slave bleeder. Then make a loose loop knot around something like the exhaust pipe. Put the tube end in the canister. Then pump the clutch up and down by hand multiple times. Watch how the brake fluid stays in the loop. keep it topped off. Once all air is out, tighten the bleeder with the pedal up. Make sure no air is in the clear tube between the slave and the loop.
The loop serves the purpose of extending the fluid system, so when the pedal is returned to the up position only air free fluid returns into the slave cylinder.
This is much easier than any other method. I usually have it done in less than a half hour alone. That includes jacking the car up and putting it on stands, which is the hardest part. Also use a stable can to catch fluid. I hate spilling brake fluid.
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  #7  
Old 07-10-2014, 11:20 AM
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Quote:
Originally Posted by C.Doner View Post
Connect a long clear tube to the slave bleeder. Then make a loose loop knot around something like the exhaust pipe. Put the tube end in the canister. Then pump the clutch up and down by hand multiple times. Watch how the brake fluid stays in the loop. keep it topped off. Once all air is out, tighten the bleeder with the pedal up. Make sure no air is in the clear tube between the slave and the loop.
The loop serves the purpose of extending the fluid system, so when the pedal is returned to the up position only air free fluid returns into the slave cylinder.
This is much easier than any other method. I usually have it done in less than a half hour alone. That includes jacking the car up and putting it on stands, which is the hardest part. Also use a stable can to catch fluid. I hate spilling brake fluid.
This sounds interesting - 'cos I'm getting old and slow - does this mean

1) long clear tube (say 4 foot long?) in a bottle / can / canister of clean new brake fluid
2) tube wrapped around something and then...
3) connected to an open bleed nipple on slave cylinder and then...
4) pump pedal?

Really that simple?
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #8  
Old 07-10-2014, 12:13 PM
GemstoneGlass
 
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The can is for catching purpose only. The fluid comes from the res.
As you pull the pedal up for the last time the fluid from the tube loop goes back into the slave cylinder. That must be free of air. If there is no loop, the fluid just runs down into the catcher can. If you pull the clutch up air goes into the system. With the loop the fluid does not run down it stays due to gravity. That leaves an air free part of the tube connecting to the bleeder. When the clutch goes up it sucks the air free fluid back. I don't even usually have to pump the pedal to get function. This works on many automotive clutch systems.
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  #9  
Old 07-11-2014, 04:42 AM
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Quote:
Originally Posted by C.Doner View Post
The can is for catching purpose only. The fluid comes from the res.
As you pull the pedal up for the last time the fluid from the tube loop goes back into the slave cylinder. That must be free of air. If there is no loop, the fluid just runs down into the catcher can. If you pull the clutch up air goes into the system. With the loop the fluid does not run down it stays due to gravity. That leaves an air free part of the tube connecting to the bleeder. When the clutch goes up it sucks the air free fluid back. I don't even usually have to pump the pedal to get function. This works on many automotive clutch systems.
Hmmmm OK - In my experience I can see that being a frustrated attempt with a W201 clutch system but I'll give it a go. Many people have reported it is virtually impossible to bleed air out through the bottom of the system even with a power bleeder.

If I get the time I'm going to mess about and see which method works the best => this seems to be one of those re-occurring problems that people have. At the moment the pushing fluid up into the reservoir trick seems to be the best / consistently reliable solution.
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #10  
Old 07-11-2014, 11:46 AM
GemstoneGlass
 
Join Date: Dec 2005
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The 230e,240d,300d 123 5 speed 717.4xx uses a w201 part number 2012900311 slave cylinder. It is the same slave cylinder for the 717.411 that I have from a 190e. The 4 speed slave cylinders are different, although they will work. I don't think it is proper, as they have different push rod lengths
I can tell the system is the same. I'm 100% sure
The manual transmission 280e has different clutch parts than the rest. The hydraulic system is still the same, just different dimensions for the parts. This is a bit off subject but it ties in somehow.
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  #11  
Old 07-11-2014, 11:47 AM
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the loop being mentioned here is the same concept that is exercised when bleeding brakes via the pump method. While bleeding brakes the bleed catch pipe and reservoir should travel upwards - this way the weight of the liquid keeps the system under and air bubbles can be seen floating upwards.

The brake caliper to clutch slave bleed is also a good and cheap way to bleed the clutch provided you have clean brake fluid in the brake caliper.

Its not much hard work to do it with the shortest brake circuit.
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  #12  
Old 07-11-2014, 12:25 PM
GemstoneGlass
 
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That method means the line from the caliper to the slave cylinder is pressurized. It can pop off spraying fluid everywhere. I've tried the pressure canister as well and have had it work. I also have had the hose pop off using that method. For me it just took forever and was kind of a pain. this is done with one nipple connection, and a no pressure line. It takes 15 minutes, 10 if you have a helper pump the clutch and fill the reservoir.
If the normal way is easy for you and you have it mastered then that is the way to go. I have a hassle trying it that way every time, and will never go back.

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