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

This must be a misprint:

"Flush brakes annually, using $2.00 or less worth of brake fluid,"

I would love to know what brand of brake fluid you are buying. No, I wouldn't. The term "flushing" suggests barely cracking the caliper fitting and squirting out a bit. Total fluid replacement is what is necessary and nothing less. After all, you don't want contaminated fluid in the master cylinder or lines either.

I have been replacing the fluid in my Porsche every two years since it was new in '84 and have never had a brake problem related to water or corrosion. And, it was a track car for about 17 years.

Anyway, it's a piddling expense. Reminds me of those who are determined to save three bucks by buying cheap antifreeze. Oops, coolant.

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Roger E.

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

If you think about the physics of how the master cylinder creates pressure within the brake lines, there is no way that it can be air tight.

Also, rubber brake lines are not completely impervious to moisture seeping through, and given brake fluid's love of moisture, a great deal of moisture can be transfered through the rubber lines.

We change our oil on a regular basis, lovingly caring for our engines. We fret over tranny fluid changes, hoping to keep that beats shifting into old age. Why make the mountain to die on brake fluid? Even having the dealer do it, it's a cheap job.

I'm not sure about you guys, but brakes are kinda important to me. I keep my brakes in top shape, and the tires under them as well. Those are two areas I don't let slide.

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John Shellenberg
1998 C230 "Black Betty" 240K

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

I don't know how important it is to flush the brake system as recommended by Mercedes, but I can tell you that I have followed this routine (along other "stupid" routine Mercedes has recommended) and I still have the same original/unopened brake calipers, master cylinder and brake lines that were installed on the car back in 1989....15 years ago and 380K later.
JackD

Yeah I know where you are coming from ;-)

.........and I agree with you. :-)

One thing though this thread certainly attracted attention :-)

It has been a good discussion.

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

I too have applied the Mercedes regiment to our other cars. I use Mercedes coolant in our other cars, change the brake fluid every two years, and so on.

Guess what? It works. On our other makes, I constantly have mechanics that are amazed at the usefull life we extract from them. I attribute it solely to using the Mercedes maintenenace regiment.

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John Shellenberg
1998 C230 "Black Betty" 240K

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

I think it's more a matter of most non-euro OEM's don't care or don't figure anyone is gong to bother dong maintinance like that so they just save the ink in the book. What does a person who buys a 94 for instance pontiac do as soon as it's out of warranty?
Take it to the cheapest place and do as little as possible and drive it till something really $$ breaks, then sell it. Or they trade it in on something still under waranty. This is the way cheap cars and cheap people generaly work. I deal with them every day of the week. I constantly replace master cylinders, calipers, radiators, transmissions, engines, anything and everyithing of late 90's cars with barely 100K on them. It's pathetic.

As others said, if you follow the common sense MB maintinance practices on other vehicles, you'll get simlilier results. I was doing this pretty much before I had ever driven an MB.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K