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I had problems bleeding my 280sl 107 the master cylinder was allowing air in. As others have said do not pump the brake pedal in the old way or you will need a new master cylinder. Not hard to change and Oreillys has them cheap and a life time warranty. Just a pain bench bleeding the master, and installing it with leaking fluid.. Also check bleeders they can leak with age and let air in.
 

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To Pump or Not to Pump? Pump.

I agree with the caution that an old, worn-out master cylinder might not survive a full-stroke bleeding session. But that's exactly why, in my opinion, one SHOULD do it.

Not only does the manual call for it (at least three strokes says 42-010, to eliminate all the air from the master cylinder). But if it IS going to fail doing that in the garage, chances are pretty good it's going to fail anyway on the next panic stop on the highway.

And total brake failure in the garage usually involves a bit less anxiety.

:)

Good road,
 

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I had problems bleeding my 280sl 107 the master cylinder was allowing air in. As others have said do not pump the brake pedal in the old way or you will need a new master cylinder. Not hard to change and Oreillys has them cheap and a life time warranty. Just a pain bench bleeding the master, and installing it with leaking fluid.. Also check bleeders they can leak with age and let air in.
Anybody have a good source for bleeders?
 

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Discussion Starter #26
I guess I should conclude this story, and perhaps it will help others.

I took off the reservoir and poked around with an inspection mirror.

Normally, in my dictionary, "fill it up" means up to the MAX line or even a little over. I came to the realization that the only way to fill the rear chamber was to go well over the max, in fact, fill it up into the gooseneck (you can see air then coming out through the breather hole).

Astonishingly just refilling to the max line does NOTHING for the rear brakes (most cars split the tank about half way down, so filling up handles both circuits. I don't know why it was designed this way or why there is no caution about it.

Anyhow, by overfilling, I finally got fluid into the rear circuit.
 

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I guess I should conclude this story, and perhaps it will help others.

I took off the reservoir and poked around with an inspection mirror.

Normally, in my dictionary, "fill it up" means up to the MAX line or even a little over. I came to the realization that the only way to fill the rear chamber was to go well over the max, in fact, fill it up into the gooseneck (you can see air then coming out through the breather hole).

Astonishingly just refilling to the max line does NOTHING for the rear brakes (most cars split the tank about half way down, so filling up handles both circuits. I don't know why it was designed this way or why there is no caution about it.

Anyhow, by overfilling, I finally got fluid into the rear circuit.
Glad to hear you got is sorted. But I am a bit puzzled. Shouldn't you get a low fluid warning if the level is low? Looking at both reservoir designs, it seems the level switch should have warned you. Maybe baffle doesn't work that way? I know when I fill with Brake fluid, I put light on other side and look for both levels. Hard to see even the one with the mark on my old cars.


PS: Thanks to Rowdie for pics ;)
 

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Discussion Starter #28
My reservoir is like the first of the two illustrations. The chamber for the rear circuit is entirely surrounded by fluid from the other chamber, not matter what side you look from, you see the level of the front circuit.
 

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My reservoir is like the first of the two illustrations. The chamber for the rear circuit is entirely surrounded by fluid from the other chamber, not matter what side you look from, you see the level of the front circuit.
Pictures were for illustrative purpose. First is early model. Second later like yours. When they get old and dirty it is hard to see the level.
 

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My reservoir is like the first of the two illustrations. The chamber for the rear circuit is entirely surrounded by fluid from the other chamber, not matter what side you look from, you see the level of the front circuit.
How about the low level alarm? Did that not actuate? Kind of scary if it doesn't work.
 

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Discussion Starter #31
How about the low level alarm? Did that not actuate? Kind of scary if it doesn't work.
No it didn't, though I was checking the fluid regularly by looking at the reservoir, which was always at the top. When I replaced the master cylinder is when I discovered this. I will need to look into the sensors.
 

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I agree with the caution that an old, worn-out master cylinder might not survive a full-stroke bleeding session. But that's exactly why, in my opinion, one SHOULD do it.

Not only does the manual call for it (at least three strokes says 42-010, to eliminate all the air from the master cylinder). But if it IS going to fail doing that in the garage, chances are pretty good it's going to fail anyway on the next panic stop on the highway.

And total brake failure in the garage usually involves a bit less anxiety.

:)

Good road,
Ditto. The extra distance in the MC is there in case it is needed. And if it is dirty and rusted and needed on the road then the MC will be destroyed and brakes not work, or work very poorly, on the next application.

Timely brake fluid flushes with full stroke of the MC can clear this crud before it becomes a problem. Keep the full length of the MC healthy. Else as GlueckAuf its best to do the damage in your garage where its safe.
 

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I found that the brake fluid with the pressurized bleeder started to come down the cap and overflow onto the reservoir body. It made a mess on the garage floor.The cap I am using is an old original Mercedes Benz cap. I am performing this on a E320, MY 2000. Any hints ?
 

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I found that the brake fluid with the pressurized bleeder started to come down the cap and overflow onto the reservoir body. It made a mess on the garage floor.The cap I am using is an old original Mercedes Benz cap. I am performing this on a E320, MY 2000. Any hints ?
If the cap fits and has a proper seal ring, that should not happen. It would also mean that the reservoir was full to the brim.

With my home made bleeder, there is always and air space above the fluid. If the cap leaked, it would only be air. In your case, any air must have leaked out around the cap causing the reservoir to be full and then fluid started coming out of same leak.

The cap I used, is actually off a Cadiilac, but is exactly same as the MB one. My car is same except 98 model.

Check the seal ring on yours as well as how you sealed the hole for the inlet.

Some pics of my unit:


 

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I just had this problem today after refitting refurbished rear callipers. When I finally gave up in a state of confusion over all the air in the system SWMBO suggested I ask you guys.
Of course when I logged in I found the answers already waiting. Such service!
 

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I agree with your diagnosis. All of the air had indeed leaked out of the reservoir. I removed the filter at the top of the reservoir and had a small tube at the center that extended down to the MAX level with the reservoir filed to the MAX. I did this to avoid introducing any air in to the system. I tried with a new rubber gasket from a new cap but the results was the same. I even tried Teflon tape around the threads with the same result. In the end I got help from my 16 yr old to manually pump the brake pedal until I could see the new fluid ( Blue ) coming from the bleed nipple on each wheel. It seems that 1 liter of fluid was enough even though I had lost quite a bit through overflow. I have another car to try it on ( s430). I think I need another gasket that goes over the reservoir but is bigger that the one that the original cap. If I have to use another cap then I have to go through the whole procedure of making holes in it and sealing the new connections. I should be able to test the system with the nipples closed to see if I can build up 15 PSI just with air ?
 

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I agree with your diagnosis. All of the air had indeed leaked out of the resevoir. I removed the filter at the top of the resevoir and had a small tube at the center that extended down to the MAX level with the resevoir filed to the MAX. I did this to avoid introducing any air in to the system. I tried with a new rubber gasket from a new cap but the results was the same. I even tried teflon tape around the threads with teh same result. In the end I got help from my 16 yr old to manually pump the brake pedal until I could see the new fluid ( Blue ) coming from the blee nipple on each wheel. It seems that 1 litre of fluid was enough even though I had lost quite a bit through overflow. I have another car to try it on ( s430). I think I need another gasket that goes over the resevoir but is bigger that the one that the original cap. If I have to use another cap then I have to go through the whole procedure of making holes in it and sealing the new connections. I should be able to test the system with the nipples closed to see if I can build up 15 PSI just with air ?
You should really discuss this in the W210 forum. I don't think you can properly bleed the brake system by pumping pedal. There may be other steps needed if you want to bleed through the ABS pump system. And for that I think you need the higher pressure. My car has ABS/ASR and your facelift car ABS/ESP (I think?). I am sure there are stickies and many discussions over in W210 on this subject ( I need to re-read them myself!)
BTW, I recall using 2L when I last did my car, but may have had some left.
 

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Thanks for the comments. I was assuming that pressure bleeding would be the same on all MBZ, since the motive unit does this by simply changing the type of reservoir cap used. The MY2000, E320 does have ABS and ESP. Anyway, I will take my comments to the W210 forum !
 

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You should really discuss this in the W210 forum. I don't think you can properly bleed the brake system by pumping pedal. There may be other steps needed if you want to bleed through the ABS pump system. And for that I think you need the higher pressure.
It would be nice if there was a way to exercise all the circuits in ABS for bleed/flush without a Star system.

I don't think higher pressures would do the job. Those ABS valves switch very high pressures, higher than the plastic reservoir will hold.
 
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