1967 200 W110 clutch help
 

Hello, i bought this Mercedes not to long ago and the clutch didnt work and the clutch master looked to be seeping. i took off the clutch and slave and found them completely backed up with gunk. I cleaned them out and tested them by putting my fingers over the clutch line holes and pressing on the piston, I definitely held pressure. I put it all back and found the flex line was clogged and leaking so I replaced that. Next I bled the clutch by connecting a line from the front right brake to the slave and had a friend push the brake pushing fluid and air up out of the clutch system.

We did this a few times but the clutch still has no resistance and just snaps to the floor without pushing out the slave at all? is it possible there is still a ton of air trapped in the master cylinder? I read somewhere else that these w110s are a pain to bleed.

clutch bleeding
 

I know I had a real pain trying to bleed the clutch on mine when I first got it. I swore for days trying different methods. A new slave, master, and flex hose later with a quick gravity bleed got me back in action. All the parts appeard to be fine when dissambled and tested on the bench, but just weren't up to the task when in service on the vehicle.

The adjustment screw at the slave cyl needs to be screwed out almost all the way. I blead mine using the Motive Power bleeder.

Slave is probably bad (leaking internally) and if the master is seeping fluid, then I would suspect that one of leaking too. Just holding your finger on it is not a good test. I replaced my slave the other day. It passed the finger test, but obviouslty was bad because the new one made the system work.

Best way to bleed it (at least for my car) is using the MB workshop method of hooking up a hose to the right front caliper and slave. Then press the brake pedal gently up and down and you press fluid (and air) from the bottom upwards.

If I were you, I would just spend the money and get new slave, master and clutch line. Once that is replaced, you are homefree for many many years.

Good luck,

Bert

That's the method I used. Do any of you know a good place I can buy these parts online or in socal?

Right at the top of the screen. Dial 888.333.4642 and a magical man named Phil will make all of your hopes and dreams come true. Although as a California resident I do believe you'll have to pay sales tax, which sucks.

Here is a write-up I did on another site for somebody with the same problem. I'll repost here in it's entirety for the benefit of others out there as well.

**********************************************************

The hydraulic clutches on these cars are one of the weakest systems in my opinion, especially as the car ages and if it sets for a prolonged period. The system consists of a master cylinder under the dash connected to the pedal, a slave cylinder on the clutch bell housing, a fluid reservoir feeding the master cyinder, and a line connecting the master and slave cylinders. When you push the clutch pedal, it pushes the piston in the master cylinder, which closes the reservoir inlet port and forces fluid to the slave cylinder to push the slave cylinder piston and release the clutch. When the pedal is released, a spring on the slave cylinder (along with the clutch pressure plate) retracts the slave cylinder, forcing the fluid back to the master cylinder, and raising the pedal and opening the reservoir inlet port when the pedal is fully raised.

What happens is a little air can get in the system, and since the pedal needs to go over center at the top of the pedal stroke, the rod in the master cylinder is not pushed quite far enough to get the pedal over center. Also, if enough air is in the system, the clutch will not release completely, causing grinding when trying to shift.

There are several things to look at. First check for fluid leaks at the master and slave cylinders. Any leaks can cause air to enter the system and will likely require a new cylinder or a rebuild kit. Check to make sure the clutch is adjusted correctly at the slave cylinder, adjusted so there is just enough stroke to keep the release bearing off of the pressure plate when the slave cylinder is fully retracted. Also check to make sure the external pull-back spring is still attached between the clutch fork and slave cylinder. And check to make sure there is not excessive travel between the pedal and master cylinder before the piston is pushed in the master cylinder by the connecting rod, but that the piston fully raises (an eccentric bolt at the pedal end of the linkage corrects this). There needs to be a slight amount of looseness in this link with the pedal fully raised to make sure the piston is fully raised. One other problem that can happen is the rubber piston cup in the master cylinder can swell so that the reservoir port is never is fully exposed with the pedal/piston up. If the hole is not exposed and you have a leak in the slave cylinder, the fluid can leak out and gravity cannot replenish fluild from the reservoir, leaving an air pocket. Air is not your friend in a hydraulic system. There is also a spring in the master cylinder that pushes the piston and cup up completely to open the reservoir port. If the spring is broke or the master cylinder piston is gummed up, the spring may not have enough force to raise the piston and cup fully, keeping the reservoir port blocked.

Another slight possibility is you could have a faulty rubber hose between the master and slave cylinder that plugs up and does not allow fluid to return to the master cylinder. I have seen this happen to front caliper brakes before.

One trick that you make need to use to get the air out is to use a Mity-Vac or similar tool to pump fluid through the slave cylinder brake bleeder and backwards through the system to purge the air. Make sure the pedal is fully raised, and it doesn't hurt to remove the reservoir cap to let air out as the reservoir fill or overflows. There is also a bleeder screw on the master cylinder that can be loosened to let air escape. Be careful with the fluid, as it can peel paint and soften rubber.

Hope this helps. I've been through this problem more than once.

A JiveTurkey said, you can get them from the forum parts vendor. I bet they are also still available from Mercedes. If the price difference is not too great, you may want to go OEM. With the amount of gunk in your system DEFINITELY buy new master, slave and hose. Don't try to rebuild them with kits if they are that gunky. Water builds up in brake fluid over time (that's why brake fluid should be flushed once in a while) and that causes the aluminum/steel internals to get pitted/correded. Rebuild kits are $10-20 each, but for $50-$100 more each you may have complete shiny new parts that last for two decades. I think new OEM MB master, slave and clutch hose were about $300 total for my car and I have that uncommon V8 clutch with special slave. Yours should be much more common = cheaper than that.

Good luck,

Bert

i replaced the master cylinder the slave cylinder and the flex line and bleed the system using the brake method. i adjusted the rods so there was just a little of play between the pedal and master cylinder. the clutch still snaps to the floor, any idea what could still be wrong?

Crawl under the car and loosen the slave a little bit. Have somebody else press the clutch. See if the slave rod is actually getting resistance from the lever that is operating the release bearing (inside the bell housing). If working properly, you should see the slave straining under pressure when clutch is pressed. If no movement, the slave bearing's rod may not be properly engaged with the release bearing lever and just poking in air. The system needs the spring action from the pressure plate to push back the release bearing and lever to push back the slave cyclinder rod and piston (and this pushes hydraulic fluid back to master cylinder and pushes back the pedal).

You could also have a broken or disengaged lever inside the bell housing that is simply not pushing down on the release bearing.

If the release bearing is broken (shattered), you may get the same symptoms because the lever has more movement than usual and will not get pushed back by pressure plate.

I just read your first post again and if this car did not run at all when you bought it, it may have been parked due to a bad release bearing. If you can crank the car, and you hear a bunch of crunching, then your release bearing is toast. They are not expensive, but you do need to take the transmission out to fix this, which is not that difficult. Sounds like you may have to take a look in the bell housing to see what is going on.

Good luck,

Bert