Tips/Experience Needed On Installing/Bleeding New Clutch Cylinders (W110 Chassis)

[Squiggle Dog]

I have a 1968 200D (W110 chassis). I would like some advice before buying new parts and tearing into it.

The car has a new clutch disc and pressure plate installed. When driving, the clutch pedal tended to stick to the floor and give inconsistent pressure.

I figured the sticking pedal was due to a clogged rubber hose and I just happened to have a spare, brand new Cohline brand clutch hose. I let the old fluid drain out of the hard line and reinstalled the new hose.

I noticed the short rubber hose from the reservoir to the hard line going to the master cylinder (inside car by pedal) was leaking. I didn't have any hose that size so I took some fuel hose and put plastic spacers in it so it would fit (not a permanent fix by any means).

I then filled the reservoir with brake fluid. I pumped the clutch for a while and then attempted to open the bleeder screw, which broke off.

I then decided to bleed the slave cylinder as the factory service manual says bleeding the master cylinder is not necessary, and early cars are not equipped with bleeder screws there. I pumped the pedal and held it down to the floor while reaching under the car to bleed the slave cylinder. I wasn't getting any pressure on the pedal. I then decided to let it gravity bleed like I have read on the forums. After many hours no fluid had come out.

I then read the Chilton's manual which said to attach tubing to a front brake caliper then the clutch slave cylinder, open the bleeder screws, then slowly pump the brakes. This made the clutch reservoir overflow and gave me a little pedal pressure at the end of the travel.

I then removed the pedal push rod so there would be no pressure on the cylinder, waited a while, then reinstalled the push rod.

I figured I wasn't going to be able to bleed the system without using the broken bleeder screw on the master cylinder. I just happened to have a spare FAG brand master cylinder that looked like it had never been used. I took it apart, honed it lightly, then reassembled (all parts looked new).

I took the original master cylinder out of the car and installed the spare. I refilled the reservoir and tried to bleed the master cylinder. No fluid would come out of the bleeder screw. I went down and bled the slave cylinder, which had fluid in it. I got a little pedal pressure at the end of the travel.

I tried and tried and couldn't get any fluid out of the master cylinder bleeder screw. I tried pumping the pedal multiple times, gravity bleeding again, taking pressure off of the clutch pedal push rod, but nothing worked.

I then wondered if there was a clog somewhere. I removed the master cylinder again and checked all of the hard lines. They were clear. I took apart the master cylinder again and checked all of the ports, which were clear. Even the bleeder screw was clear.

I put it back together and reinstalled in the car. Same thing. My roommate was able to get fluid out of the master cylinder bleeder screw if he sucked it out with a tube, but nothing would come out on its own. We alternated bleeding the master and slave cylinder, but nothing. Finally I opened the slave cylinder bleed screw as he pumped the pedal. Bubbles kept coming out of the slave cylinder into the tubing no matter how long he pumped it.

It was suggested to me that one of the rubber cups may be blocking the bleeder screw hole and not allowing air or fluid to escape out of it. I heard you can remove some of the material on the metal plunger piece to get the rubber parts to set higher and not block the hole.

Now my plan is to buy new master and slave cylinders (or a good rebuild kit). I was planning on going with OEM (ATE or FTE, right?) so I know I'm getting good parts. I also need to replace the short rubber hose that goes from the reservoir to the hard line. Any suggestions for the proper hose? I will probably go OEM since it is a small piece. The fitting at the hard line from the master cylinder to the clutch hose has slightly damaged threads and I would like to replace this hard line. Hopefully I can get an OEM one not too expensively. I have a new Cohline clutch hose which works (and was $44--ouch).

Do I need to bench bleed the new cylinders, and if so, how do I do this? Obviously the master cylinders seem to have a problem with trapped air. I'm just looking for any advice before I order the parts and install them. I want to stick with OEM as much as possible and stay away from bad brands. I also want to know if I'm supposed to bench bleed a cylinder before I install it in the car and can't get it to bleed.

Is teflon tape recommended? I don't think it would be good at the fittings as it could cause a clog, but maybe at the bleeder screw it would be beneficial?

[johnjzjz]

OK try this before you spend anymore money

Bleading the clutch with no pressure at the pedal if it just flops around

get a hand pump oil can clean it very very good put your brake fluid in it install a vacume hose that fits the bleader onto the spout and pump some brake fluid out - soo far i hope your with me

than attach to the bleader and pump fluid from the slave UP to the master maybe 20 pumps than tighten the bleader -- before you take the oil can off try it and see if the pedal now extends the clutch rod if so blead the regular way if needed -- good luck - jz

[Squiggle Dog]

I pumped fluid up from the slave cylinder to the master cylinder. It goes through the master cylinder and fills the reservoir to the point of overflowing, but nothing more than a dribble comes out of the bleeder screw (even with the screw removed). The bleeder screw hole and bleeder screw are clear, but it's like fluid just won't get to that point.

[soothappens]

Originally Posted by Squiggle Dog

I pumped fluid up from the slave cylinder to the master cylinder. It goes through the master cylinder and fills the reservoir to the point of overflowing, but nothing more than a dribble comes out of the bleeder screw (even with the screw removed). The bleeder screw hole and bleeder screw are clear, but it's like fluid just won't get to that point.

If you reverse bleed it from the slave cylinder and tighten the bleeder after seeing fluid going to the resevoir you should have a good pedal. If not you have worn seals. As far as parts go skip the rebuild kits. If you need the component buy it already assembled. My master cylinder was bought new and continues to work , while my slave cylinder I rebuilt it lasted a year at best. Started leaking last night 20 degree weather !!! So at 20 dollars plus labor your not saving much. I also rebuild hydraulic cylinders for a living so this was small potatoes. After 30 years something gonna wear. Try reading this thread

Quick clutch bleeding question!

[Squiggle Dog]

I tried getting new cylinders from the dealer and Classic Center, but apparently they are not currently available. The original master cylinder has a corroded inner metal piece and the bleeder screw is broken off in the housing, so it's not worth rebuilding at the moment. I have a set of new FTE cylinders on the way.

When the cylinders get here, hopefully it's just install, fill, bleed, and done. I hope I don't have any problem bleeding the cylinders anymore.

[Squiggle Dog]

I am VERY happy today! I came home from a 20 mile round trip by bicycle to work and back very exhausted and barely able to walk. I can coast much of the 10 mile distance on the way to work, but coming back is entirely uphill and there is almost no coasting.

Not long after I got home the dogs were barking and I looked outside to see the FedEx truck. My new clutch cylinders that I ordered the day before yesterday were here already! I ordered them from Germanautoparts.com because The Classic Center did not have any. The company is based in New York, so I figured I would get them in maybe a week if they had them in stock. What a nice surprise this was.

AND, that's not even the best part--I ordered FTE brand cylinders because my first choice of OEM ATE brand was not available (and I would have paid the high dealer prices for them). The boxes said FTE-FAG on them. But, what was inside were nice, new ATE brand cylinders just like the original ones that my car was made with! That totally made my day. I paid an off-brand price and got OEM parts.

Now with the 3 day weekend coming up I should be able to drive my car to work next week. No more biking or riding the expensive buses with scary people on them (at least for a while).

Hopefully the parts I did order from The Classic Center will arrive by the weekend (small reservoir hose, bellhousing boot, and radiator cap, plus stuff for my roommate).

[Squiggle Dog]

As usual, my boss held me after work a few minutes so I had to hurdle over a hedge and run full speed to the bus stop so I could catch the bus (he gets mad at me for doing this, but if he had compassion and let me off work on time or maybe even a couple minutes early I wouldn't have to run and "jump dangerously" to catch my bus so it doesn't take me an extra hour to get home).

Shortly after I got home the FedEx truck came by and it had my parts from The Classic Center! Now I can use the coming 3-day weekend to get my car back on the road so I don't have to deal with all of this drama.

Do I need to bench bleed the new cylinders, or do I just install and bleed them after?

[soothappens]

Originally Posted by Squiggle Dog

As usual, my boss held me after work a few minutes so I had to hurdle over a hedge and run full speed to the bus stop so I could catch the bus (he gets mad at me for doing this, but if he had compassion and let me off work on time or maybe even a couple minutes early I wouldn't have to run and "jump dangerously" to catch my bus so it doesn't take me an extra hour to get home).

Shortly after I got home the FedEx truck came by and it had my parts from The Classic Center! Now I can use the coming 3-day weekend to get my car back on the road so I don't have to deal with all of this drama.

Do I need to bench bleed the new cylinders, or do I just install and bleed them after?

Install them and bleed afterwards reverse bleeding is what works best . Make sure when you take your foot off the pedal your master cylinder lets oil return to the resevoir . best of luck

[Squiggle Dog]

I installed the new cylinders and tried everything I know of and have read about, but still can't get all of the air out of the system. The only time I got any pedal pressure was when I attached a hose to the brake caliper and pumped the fluid up into the master cylinder. Further pumping just made the clutch reservoir overflow with no additional pedal pressure. I adjusted the slave cylinder rod all of the way out which made the car drivable, but the pedal is mushy and does not spring back. I am through with this game, so I am going to limp the car over to the local independent Mercedes repair shop to have them bleed the clutch.

[Squiggle Dog]

I drove the 200D over to the independent Mercedes repair shop. They said that there is no air in the clutch system, but that something inside the bellhousing is wrong. The throwout fork moves almost to the end of its travel before there is any resistance. When I installed the new slave cylinder I remember the throwout fork feeling very rough and loose. I wonder if maybe the throwout fork popped off of the pivot ball or something.

It has a brand new Sachs clutch and pressure plate that was installed maybe a year ago when the previous owner had it.

What's happening, with the slave cylinder pushrod lengthened out to the max, is the clutch does not release until the pedal is near the floor. The slave cylinder pushrod travels a good distance, but the throwout arm moves a long ways before it hits anything in the bellhousing and starts to release the clutch.

I guess I have to open the inspection covers to see what is going on. It is not a good time of year to have to drop a transmission and replace parts that were already replaced recently.