ChuckinTucson

Yesterday while at the dealership for a minor recall, they did an inspection of the car and said that while not presently at a critical level, the transmission fluid needed changing. I have 42,000 miles on the car (05 C230). They quoted a price of around $400. I've heard of changing the transmission fluid before, but not sure of the price and/or if it would need to be done at 42,000 miles.

The other item that really surprised me though was that they said the brake fluid also needed changing (at $130). I've never heard of having to change brake fluid.

Can somebody shed some light on this for me?

PA_Pete

Brake fluid (according to the Owner's Manual), I think should be changed every two years. I forget exactly how it works, but your brake fluid gets pretty dirty over time and absorbs moisture (I think). So, it wouldn't hurt to have the brake fluid flushed and changed. If you are a DIY'er, I would go that route, it's not that hard, at least on other vehicles, I've never done one on my MB yet. As for the ATF, I don't believe you need to have that done till at least 60,000 miles. Do you have the 5 speed or the 7 speed auto?

ChuckinTucson

Thanks for your insight Pete. The car has a 5-speed automatic.

mleskovar

$400 sounds like it's for what they call a 'transmission service'. Change filter and drain transmission sump. It only gets rid of about 1/2 the fluid but you should do it. After first transmission filter change you can just drain and refill every 50K or so. $400 is too much for that service though. Brake fluid is hygroscopic....it attracts water. Water dilutes the effectiveness of the fluid, can boil and cause problems, and reacts adversely with brake parts...especially the ABS system. Change it. I would go to an independent for these services if you don't want to do them yourself. You'll save $, I'm guessing an indy would do both for $325.

PA_Pete

Thank you for clarifying!

C230 Sport Coup

I'm known for being a big DIY'er, but I paid to have my
brake fluid flushed, since it's soooo much easier on a lift, draining
each corner of the car on a flat surface.
DIY'ing would requires gaining access to the brake valves on each corner, not an easy feat on a lowered car. + I'd need one of those pressurized brake fluid things.
100 bucks well spent to prevent issues with the ESP system.

I've NEVER heard of a dealership actually recommending replacing the tranny fluid on a 5 speed.
Standard for dealers is to says it's a "lifetime" fill.

Did they say why they are recommending replacing the fluid?
Is there glycol in it?
If you search you'll find many discussions on the transmission fluid issue.
I did mine at 120K miles, but I wish I'd done it sooner.

As stated on our cars, since MB saw fit to remove the drain plug from the torque conv. back in like 1999
as cost cutting measure, you can only get about 4 of the 9 quarts of fluid out of the car.

The only time MB recommends a complete flush is if the fluid is contaminated.
Otherwise, it's just drain and drop the pan and replace the fliter.

Perhaps if this was done regularly, like every 40-60K miles, maybe that would be sufficient.

I paid to have mine flushed by a dealer around 80K but I have doubts they did the work at all.
And as stated, they only replaced 4 quarts according to the invoice.
I had the fluid tested at 120K and it was crap, gone, fried.

mleskovar

Yea, I was one of those people that said "trust MB, they know what they're doing with 'lifetime' fluid recommendation". Just to be safe I periodically tested the fluid and at about 130K the fluid was kaput.

Me too, then just draining the sump and refill every 50k should keep the fluid up to snuff.

BlackLiquorish8

i did both at 50 and plan on doin both again at 100

altho i heard theres no need to change the coolant but i'm planning on doin it this summer.

speakin of fluids my car is due for an oil change!

TemjinX2

for the tranny just diy. Even you buy the pump and all the tools needed for the change, it'll still be less then $400.

Trust me, you want to change it..i changed mine at 80k and the fluid was black and lot metel shards on the magnet.

Glyn M Ruck

Mleskovar is absolutely correct about brake fluid being hygroscopic. Change every 2 years

Mercedes Benz South Africa recommends a transmission fluid change on the 5 speed at 60,000Kms (40,000 miles roughly) & do this free under the service plan. We are considered a torrid zone in Benz speak. I recommend you do the change. That filled for life BS was an American thing & cost someone a lot of money - MBUSA or owners???

ChuckinTucson

Thanks again for all your input. I live in Arizona, so it does get pretty hot and dusty here. They said both the brake fluid and transmission fluid were dirty and contaminated. I'm not a DIYer, so will find a good independent and see what kind of prices I come up with. Will report back after I speak with them, although the car is going to be sitting for a while as I'm headed to Michigan this afternoon.

Glyn M Ruck

Yes - I drove through Arizona when I lived in Dallas - It's very like some of the harsh parts of South Africa & Namibia where Benz do most of their high temperature testing. Find a good Indy & have it done. I'm like you. I don't work on my own car anymore. I leave that to my very good dealer. But I help friends work on their's - Crazy!

PA_Pete

I changed out my coolant when I did the radiator swap, I had the Valeo and swapped that out for a new Behr radiator. The coolant looked fine to me, but again, I'm no pro with anitfreeze!

I did my tranny flush at 70K miles, I did it the same time I did the radiator swap, figured it would be easier to do all at once. The fluid was BLACK! Now, check this out, if you refer to the Tranny DIY thread, I mention that in my trans pan, I DID NOT have any magnets! I thought that was really weird.

TemjinX2

me and you think alike. Yeah i changed my tranny fluid when i installed my new radiator as well. You sure it wasnt there? The magenet is really small...its actually that small flat piece of metal with the vents on it. I didnt notice it until splinter took it out from the drain pan.

I probably never would noticed it, since on all the honda's i worked on, the magnet was always the drain bolt.

Glyn M Ruck

If the fluid was black it needed changing - it was oxidised. Any severe darkening of tranny fluid is a sign it needs changing. Slight darkening is all that should be tolerated. The fluid should remain clear & bright or be changed.

Moviela

I hate to be the one to toss a turd in the punch bowl, but you don't change the brake fluid because it has soaked up water from the air. It is true that brake fluid is hygroscopic, but at two years there is hardly enough to cause any significant corrosion. It is usually less than 1% moisture, even after many years. The color of the fluid has nothing to do with whether it should be changed. Dirty fluid can be fine for service, while clear fluid can have corrosion inhibitors exhausted and be unfit for use. So why do we change brake fluid every two years?

Copper. Brake fluid also absorbs copper, and the Cu depletes the corrosion inhibitors and tends to re-plate itself in the nooks and crannies of the ABS passages.

It is not possible to measure moisture in brake fluid in the workshop, but you can use a test strip to indicate the amount of copper in the fluid. This can give an indication of the age and condition of the fluid.

With respect for the recently departed Paul Harvey, "Now You Know the Rest of the Story."

Some light reading:

http://www.babcox.com/editorial/bf/bf50412.htm

Jack_2001C240

Very informative post about copper contamination in brake fluid. Thanks.

RedG

The moisture does affect rubber seals, and flexible brake lines, or even steel brake lines internally.

Glyn M Ruck

Moviela - You are not throwing the crap anywhere - this is a very good article, if somewhat out of date, as newer fluids are in some respects even more susceptible to these problems, especially water, and in other respects better counteract these issues.

The catalytic effects of copper & it's alloys, on oxidation & corrosion are well known to the industry as is copper redeposition in systems such as Fuel systems when using alcohol fuels, Braking systems & automotive HVAC systems when using certain synthetic lubricants containing desolved refrigerant. All situations are aggravated by water & extremes of temperature - both cold & hot.

At the same time high water concentrations that develop at the wheel (Caliper & flex pipes) are more than sufficient to cause localised boiling of the fluid as frequently shows itself on a long run down a mountain pass. I accept that this is somewhat ameliorated by the actions of the ABS system on the fluid & in some respects made worse.

I think, in the absence of sophisticated testing equipment, keeping the fluid visually clear & bright & water free is prudent.

OEMs know all the constituents of their systems and in the case of Benz I would not advocate to anyone moving away from a 2 year fluid flush & change even if it proves to be overkill for a specific situation. One has to plan around a worse case scenario. We could debate at length but for the sake of forum members - Change your fluid every 2 years - Moviela's posted article does nothing but to provide you with some more information as to why.

jcnash

Hey guys,

Sorry if this has been covered elsewhere....but I STFF'd like crazy and still couldnt find it.

So, is the brake fluid and tranny fluid replacement a DIY job? If so is there a guide on MBW?

Thanks.

Glyn M Ruck

Here:

https://mbworld.org/forums/c-class-w...n-related.html

The brakes are dead easy - I will try & find you a proceedure

johnand

Brake bleed/flush:https://mbworld.org/forums/c-class-w...ng-brakes.html

07 Benz

I was under the impression the 7speed tanny fluid should be flushed around 30k... is that not accurate?

johnand

38K miles according the the MB Service Schedule. The original poster has the older 5speed transmission that had a bogus Service Schedule of "lifetime fill". General wisdom on that transmission is change every 50K.

For the 7G, ROW (Rest of World) has an EVERY 38K mile change interval.

Glyn M Ruck

Listen to John - I would change all 722.6 & 722.9 transmissions' fluid every 38,000 miles or 60,000 Kms.