Best option for 3.5 clutch system bleeding? - PeachParts Mercedes-Benz Forum

sjefke · #1 07-18-2006, 04:42 PM

What is the best option for bleeding the clutch system on a 111 280SE/c 3.5?

I read a number or threads and can't quite figure out whether I should get a power bleeder (e.g., Motive) or do it the MB workshop manual way (hose from brake nipple to slave nipple). I am tempted to buy a power bleeder, but I cannot figure out whether I still would have to bleed the clutch from the bottom up, or will a power bleeder work top-down?

Any advide would be appreciated. Blleeding the clutch is all that stand in my way of driving the car again.

I have my 4 speed back in the car with a new pressure release bearing AND a guide sleeve that was totally missing when I pulled the tranny. I changed the yoke as well (from donor transmission). I started the car today without a problem. No grinding metal noises anymore from the bellhousing! I choose not to replace the pressure plate and clutch disk because they had been replaced in the 1990s. So all in all it was a pretty cheap repair (parts wise), but I did end up buying a spare pressure plate and complete transmission as well (just in case).

Bert
1970 111 280SE/C 3.5 (4 speed)

cth350 · #2 07-18-2006, 08:58 PM

The hose from the brake booster is the way to go.

BTW, in your travels, did you come across a spare flywheel? I need a 2nd one. Thx -CTH

sjefke · #3 07-19-2006, 10:26 AM

Quote:

Originally Posted by cth350

The hose from the brake booster is the way to go.

BTW, in your travels, did you come across a spare flywheel? I need a 2nd one. Thx -CTH

I assume you mean connecting a hose from right front caliper to clutch slave and use brake booster to pressure system, correct?

Sorry, no spare flywheel. I bought the spare transmission from Potomac German parts on Ebay and I asked them whether they had flywheel and other parts for that car. They said the transmission was old inventory and they had nothing else. But who knows, maybe they have the flywheel still lying around in inventory. I don't think there was much demand for this transmission. It had been on Ebay before and nobody bid on it. They even ate some of ths shipping cost. They listed it as coming from a 116 car (maybe they meant m116..). Anyway, bellhousing is identical to mine. German Star in AZ had the pressure plate for a very reasonable price (cheaper than anywhere else). You may try them too. They seem to know their clutch stuff.

I did see a year ago a complete M116 with four speed attached in Germany (german ebay) for Euro 100. Not that it helps you know, but they do pop up occasionally over there. Search for Mercedes 'getriebe'.

Thanks,

Bert
1970 111 280SE/c 3.5

autozen · #4 08-08-2006, 10:15 PM

Bert,
I'm only going to say this once. You wil probably get a whole bunch of answers from excitable DIYs, but here is what has worked flawlessly for 30 years, and it was tought to me by German MB mechanics when I was an apprentice. Get a TOP QUALITY OIL CAN LIKE PLEWS. If you buy a piece of crap from Harbour Freight, it won't work. Fill it with brake fluid, put a short hose on it, connect it to the slave bleed screw. open the bleed screw, and pump the oil can until you see fluid in the reservoir. Close the bleed screw, and you are done. It is that simple.

kpb · #5 08-08-2006, 10:22 PM

Quote:

Originally Posted by autozen

Bert,
I'm only going to say this once. You wil probably get a whole bunch of answers from excitable DIYs, but here is what has worked flawlessly for 30 years, and it was tought to me by German MB mechanics when I was an apprentice. Get a TOP QUALITY OIL CAN LIKE PLEWS. If you buy a piece of crap from Harbour Freight, it won't work. Fill it with brake fluid, put a short hose on it, connect it to the slave bleed screw. open the bleed screw, and pump the oil can until you see fluid in the reservoir. Close the bleed screw, and you are done. It is that simple.

Peter -- have no idea why I am reading this thread but, you are awesome, dude...

autozen · #6 08-09-2006, 11:04 AM

kpb,
I'm taking that as a compliment.

Tony H · #7 08-10-2006, 10:44 AM

This is good information. I will be getting my rebuilt trans back from Mercedes Werkstatt soon and installing it.
Tony

fastpakr · #8 08-10-2006, 10:48 AM

I agree with kbp on this. Whenever possible, any hydraulic system should be bled with a single person and a constantly open bleed valve. The absolute ideal system if you don't need to flush is to route the bleed line back to the master cylinder of whatever unit you're bleeding, but that isn't always possible. Much easier and more reliable than working with two people and constantly opening/closing the bleed valve.

autozen · #9 08-10-2006, 11:00 AM

Quote:

Originally Posted by Tony H

This is good information. I will be getting my rebuilt trans back from Mercedes Werkstatt soon and installing it.
Tony

If your talking about Mercedes Werkstatt in Mountain View, you couldn't have made a better choice. Paul is the best in the Bay Area since Peter Schmidt retired.

Arthur Dalton · #10 08-10-2006, 12:55 PM

Quote:

Originally Posted by autozen

Bert,
I'm only going to say this once. You wil probably get a whole bunch of answers from excitable DIYs, but here is what has worked flawlessly for 30 years, and it was tought to me by German MB mechanics when I was an apprentice. Get a TOP QUALITY OIL CAN LIKE PLEWS. If you buy a piece of crap from Harbour Freight, it won't work. Fill it with brake fluid, put a short hose on it, connect it to the slave bleed screw. open the bleed screw, and pump the oil can until you see fluid in the reservoir. Close the bleed screw, and you are done. It is that simple.

I agree.. clutch slaves get bled from the bottm up to the res.

I have a DIY jar with a squeeze air bulb on top [ from a blood pressure cuff, of all things]
You simply poke a couple of holes in the top of a good sealing, clear glass jar. Put a clear plastic hose through one hole and the other is the pump bulb.
Fill it 1/2 way w/fluid and with the clear hose in the fluid, pump the bulb a few pumps [ this only amounts to 5-10 psi] The reason for clear hose/jar is so you can watch fluid levels.......
Other end of hose goes on the slave bleeder , which you open. The PSI from the bulb will force the fluid into the the bleeder and push any air in the system out the res.
This same cuff bulb can also be used for brake bleeding with one person. I have one that just hooks to an extra res. cap and simply pump it a couple of times and open the caliper bleeder . Works fab.........just keep an eye on res level.
What is nice about the cuff bulb is it has a valve release knob on it to relieve the pressure. The same one they use when taking your Blood Pressure.

Tony H · #11 08-10-2006, 08:30 PM

Yes Paul has my transmission(for a year this Sept) I told him to take his time and I guess he believed me. It dosen't really matter because I'm doing other work anyway and not ready for the trans yet. I also had my driveshaft rebuilt at Portland Driveline-I have heard great things about them.
Ton

autozen · #12 08-10-2006, 09:19 PM

Quote:

Originally Posted by Arthur Dalton

I agree.. clutch slaves get bled from the bottm up to the res.

I have a DIY jar with a squeeze air bulb on top [ from a blood pressure cuff, of all things]
You simply poke a couple of holes in the top of a good sealing, clear glass jar. Put a clear plastic hose through one hole and the other is the pump bulb.
Fill it 1/2 way w/fluid and with the clear hose in the fluid, pump the bulb a few pumps [ this only amounts to 5-10 psi] The reason for clear hose/jar is so you can watch fluid levels.......
Other end of hose goes on the slave bleeder , which you open. The PSI from the bulb will force the fluid into the the bleeder and push any air in the system out the res.
This same cuff bulb can also be used for brake bleeding with one person. I have one that just hooks to an extra res. cap and simply pump it a couple of times and open the caliper bleeder . Works fab.........just keep an eye on res level.
What is nice about the cuff bulb is it has a valve release knob on it to relieve the pressure. The same one they use when taking your Blood Pressure.

Arthur,
That is an incredibly clever approach. It sounds like it works well. That is a good point about the clear hose. The reason I was emphatic about the quality of the oil can was because I used a black rubber hose on a cheap can, and it took a lot of wasted time for me to realize the cheap can was back bleeding.

Arthur Dalton · #13 08-10-2006, 09:31 PM

Thanks..

The trick on the cap entrance holes is to make them just a bit smaller than the hose.. that way, when you press the hose into the hole, there is no need for any gaskets as the hose will self-seal just from being oversize.
Another trick is to use a gas tank clunker from a chain saw or weed wacker on the end of the hose.. this keeps the hose on the bottom and filters out any dirt in the fluid.

I use a nipple for the cuff bulb so that I can use the same bulb for both the jar and the master cap when brake bleeding.. Works great on both systems .. you can find the pump at any yard sale for a couple of bucks..they usually even come with a stetoscope.so that can come in handy too...
Another trick on brake bleeding is to put another clear hose on the caliper bleeder draining into an open container.. this allows you to see any air bubbles in the drain line so that you know when you are done.. also lets you monitor fluid color.. I usually put a loop in this line so I can watch the air pocket/bubbles flow rate better..

autozen · #14 08-10-2006, 09:52 PM

Quote:

Originally Posted by Arthur Dalton

Thanks..

The trick on the cap entrance holes is to make them just a bit smaller than the hose.. that way, when you press the hose into the hole, there is no need for any gaskets as the hose will self-seal just from being oversize.
Another trick is to use a gas tank clunker from a chain saw or weed wacker on the end of the hose.. this keeps the hose on the bottom and filters out any dirt in the fluid.

I use a nipple for the cuff bulb so that I can use the same bulb for both the jar and the master cap when brake bleeding.. Works great on both systems .. you can find the pump at any yard sale for a couple of bucks..they usually even come with a stetoscope.so that can come in handy too...
Another trick on brake bleeding is to put another clear hose on the caliper bleeder draining into an open container.. this allows you to see any air bubbles in the drain line so that you know when you are done.. also lets you monitor fluid color.. I usually put a loop in this line so I can watch the air pocket/bubbles flow rate better..

The only caveat I can offer here is not to open the bleed screw too much, because it will suck air through the threads which will look like air in the system.

Arthur Dalton · #15 08-10-2006, 09:57 PM

Quote:

Originally Posted by autozen

The only caveat I can offer here is not to open the bleed screw too much, because it will suck air through the threads which will look like air in the system.

No.. the line has pressure from the bulb PSI , so there is no suction side vac as long as you see flow...
.. which is why a vac pump on the caliper bleed line is an inferior way to bleed , as that will result in air entering the bleeder threads, as you suggest.
This will not happen with a pressure system as long there is PSI pressure from the pump. If the bleeder is open too far , the results on this system will be fluid coming out the bleeder threads , not air entering ..
..which is why we want to see flow rate at all times.[ thus the clear hose concept]