I believe the ABS system is more sensative to old moist brake fluid.

Here's how I look at it...

The single largest cost of buying a Mercedes is the depreciation. After that, we lay out cash for gasoline and insurance. Lastly, we have maintenance and repair costs. On a per mile basis, changing the brake fluid and coolant every other spring is cheap. REALLY cheap in the grand scheme of owning one of these cars.

I reduce my operating costs by doing most of my own maintenence, but the other reason is so I know the work is done to my own standard.

Our own 190E is 15 years old. It runs great, and is a great car. It's not worth much anymore, but through MB's maintenance regiment, we've got nearly 400,000km's of solid running out of it, and it has many more miles left.

It works.

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John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

When you compare how the brake fluid looks, after only a year, to new fluid, the answer is pretty obvious.

Brian

Hey yosshimura, Don't flush your brakes for a couple of years. Then bring it in my shop for repair. Reading your posts seems like you are always complaining and whining about mb's. You always complain about Mb's dealerships, shops and services. You need to get rid of your Mb and get a corolla or honda, even a Kia would seem to fit you properly. Then you can also get rid of that fake rolex and get a real one.

LOSER

Jerry... its all right to be pimpin' on a budget

I can tell you that the brake fluid on my 86 560sl, which had supposedly been serviced 6 years earlier, looked like rusty milk. Worse, I had to replace all four (4) calipers. One was totally frozen, 1 was very stiff and I'm sure was going to fail in the next several months, and the back two were found to be seriously pitted after I had disassembled them (with great difficulty) for inspection.

The prices for NEW calipers are eye-popping. I don't think you could get 4 for under $800 and never mind the PITA/expense of installing them. I got rebuilts from advance auto (so far, so good). So, especially if you do the fluids yourself, preventative maintenance can be a money saver.

Now, as far as the safety is concerned; what you have read about boiling points and the hygroscopic nature of this stuff is true (I read up on this because I couldn't beleive it either). Your brakes will NOT be as good in an emergency if you don't change the fluid every few years, never mind the corrosion issue. This isn't a property unique to MB cars and brakes.

Very new cars may be using a newer fluid, which is much better and not as hygroscopic Unfortunately, as far as I have read, you can't just replace the older-style fluid with this stuff unless you have the whole thing professionally flushed, which is probably beyond my MITIVAC. There may also be compatibility issues with the rubber hoses.

It seems that the original question was why does MB recommend flushing the brake fluid while other manufacturers don’t? The inference being that this must be due to an inherent weakness in MB’s brake system. I think enough information has been provided on this thread as to what happens to brake fluid overtime. The weakness is in the nature of break fluid as the two links below explain. If other manufacturers choose not to recommend flushing then that’s their problem not MB’s for failing to alert their customers. From a business standpoint it makes sense. They get to replace a lot more expensive brake parts than MB owners, who flush their brakes biannually, do. Is MB at fault for alerting their customers or are the others at fault for not including this straightforward procedure as part of their regular maintenance program?
http://www.osbornauto.com/questions/bfluid.htm
http://www.rpmnet.com/techart/fluid.shtml#fluid

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Riadh
'89 560SL Rauchsilber
And what is good, Phaedrus, and what is not good -- Need we ask anyone to tell us these things?

yosshimura hs a point. His Pontiac is running fine and the MB needs brake fluid changes. My Volvos need brake fluid changes too. The reason the Pontiac doesn't require brake fluid changes is because the master cylinder has a bellows built in to the seal between the master cylinder and the cover. As the brakes wear and the fluid level decreases, the bellows is drawn down.

European cars have a vented cover, the older American cars don't. Perhaps the newer American cars do. Those cast iron master cylinders sure were heavy.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

yosshimura, your 3.2 engines requires 7-7.5 Qt of oil, vs a GM 3.4 engine which requires 4-5 Qts.

More oil means that the percentage of contaminants is less.

Is the brake fluid capacity higher for an MB vs other makes?

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Zafar
94 E320 58000 Miles

But not much of a point.

Brake hoses are made of rubber too and they allow air/moisture to migrate across cell boundaries.

Also, most motorcycles have a similar brake reservoir arrangement to the one you describe - and I can only speak about Suzuki here - but they also recommend 2 yearly fluid changes.

As I posted originally, it is only a recommendation but - there is a horrible cost in finding out you made a poor judgement call in saving $30 or so!!

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NormanB
230 TE (W124) 1989 with 153,000 miles on the clock - hoping for at least another 100K

I would be willing to make a VERY LARGE bet that your 75 Pontiac, or whatever it was, has not gone almost 30 years with no brake hydraulic attention.

My MB's, with annual brake flushes on the other hand, have never had any hydraulic attention and still work fine.

As stated earlier in this thread I'm sure, brake fluid absorbs moisture, moisture makes corrosion. Regardless of what you drive you have two choices. Flush brakes annually, using $2.00 or less worth of brake fluid, or periodically do expensive brake hydraulic repairs. Your choice.

Have a great day,

1. German cars, not just M-B, have service recommendations which assume they will be driven under autobahn conditions, which means the manufacturers have to be concerned about the effects on brake fluid of repeated stops from very high speeds. Extreme hot and cold cycles do increase the hygroscopic rate of the fluid. Mountain drivers, take note.

2. Water absorption in humid climates, obviously, is a bigger issue than it would be in the New Mexico desert or in a very cool but relatively dry climate. We never had big rust problems with old brake fluid when I was a kid in Minnesota, but here in Tidewater Virginia, I would definitely follow the every two year recommendation, as I would if I were forced to live in Florida.

Therefore, you can apply a certain amount of critical judgement to the brake fluid change interval, but you'd better be sure that you really know what you are doing. It is also true, as someone else suggested, that old Pontiacs' service schedules assumed that the brakes would wear out often enough that the fluid would be changed as part of wheel cylinder rebuilds every couple of years. For those who just threw on a new set of shoes without even looking at the cylinders, this could be disastrous.

Fimum Fit,

You bring up a very logical point. In the drum brake days it was just common knowledge that when you replaced shoes, you cleaned, honed and replaced the kits in the wheel cylinders. If you didn't it was a virtual guarantee that you would be doing so soon afterwards.

Those cylinders pitted like crazy. Most calipers have stainless parts and the seal is in the cylinder rather than on the piston, or at least move with the piston.

Even with those old systems, annual brake flushing would have kept them in much better shape, and required much less trouble at brake time.

Have a great day,

Brake fluid has to be changed after some interval, longer or shorter, all fluids in the car do.

All German manufacturers require the brake fluid change to be done each 2 years, even in the old VW Bugs(drum brakes all around) the recommendation was the same. In my 1966 Bug(now in repairs ) I've not changed it for 2 and a half years, not even completed in the meantime, and when I've looked at the reservoir, the liquid inside was black. Not "a bit rusty", like others say, but black like sewage. Obviously I've drained immediately the brakes and refilled...

Conclusion: you may change the fluid in the Pontiac or Mercedes, or you may leave it as it is. It's your risk

~Nautilus

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1990 260E Sportline (that's 300E 2.6 for our American friends) -> sold
2001 E320 4Matic Elegance -> my Dad's daily drive
2005 Seat Leon FR 1.8T

But they do exist.

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NormanB
230 TE (W124) 1989 with 153,000 miles on the clock - hoping for at least another 100K