2003 Mercedes-Benz SL-Class - No brakes

Didn’t drive the SL500 for over two months. 55,000 mi. This was during a cold spell- temp dropped to -7 one morning. Several days later she started fine, but when I pulled out of the garage, I discovered I had no brakes! Downhill! Fortunately, I drive better than the average bear and avoided any mishap. Cars brakes may have been a little mushy the previous time I took it out. Brake fluid reservoir was full to the brim. Any ideas?

Don’t take chances. Have it towed. At the minimum it needs bleeding.
When was the last time you had the brake fluid flushed?


Just like Purebred posted , have it towed to a brake shop . All you will get from the web are things that might be wrong and still not solve your brake problem.


@edward09, they mean tow it to your repair shop, not a chain store. I’d always use a trusted mechanic for any work, especially on a fine classic like an SL500.

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A master cylinder with an internal leak can do this. Cold can exacerbate it.

Reminds me of a friend who sold me a much-used Toyota Corolla wagon: “The brakes work. You just have to pump 'em.” A new rebuilt master cylinder was my first significant repair.

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I don’t call that “working”! :roll_eyes:

I think you’d agree!

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I learned to drive on two cars, a model A with cable brakes that always needed adjusting and a 41 Studebaker Commander that you had to pump up. I still take corners too fast !

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So a 20 year old car with exceptionally low mileage (low usage) … probably the brake fluid has never been flushed and maybe the pads haven’t been changed in 10 years or never?

First, your brakes system uses lots of “rubber” piston seals which deteriorate with time allowing fluid in the calipers to leak out and air to leak in or “blow past” the pistons. possibly the cause of your “mushyness”.
Next, besides actuating your brakes, the brake fluid also serves to lubricate the piston seals which after a period of sitting would tend to “freeze” in place.

Either way it’s time for a comprehensive evaluation of the complete system, understanding that if the seals are failing in any one area the rest are probably not far behind.


Still have the Commander?

Looks like we have another drive by poster.

Concur to not drive SL-C until brake problem resolved.

No braking function at all and brake fluid levels ok? hmmm … Cold temps might conceivably cause a master cylinder problem, but even it such a thing happened, seems unlikely it would result in no-braking at all. I’m thinking something is preventing the master cylinder from being actuated when the brake pedal is pressed. Check linkages at brake pedal and power booster.

What else? Well, if normal braking returns when engine compartment warms up, maybe there is a thin layer of water at the bottom of the MC that froze and blocked off the ports. In that case drain and replace brake fluid. I wouldn’t have guessed water would form layers in brake fluid like it does in gasoline, but maybe in certain situations it does.

OP, when you say you have no braking, does the pedal go all the way to the floor? Or does it stay firm, but the car won’t stop? The frozen water theory, seems like the symptom for that would be the pedal would be firm but car wouldn’t stop. Another thing to try, look at the inside of each wheel while a helper presses on brake pedal. See anything leaking down the side of the wheel?

This particular car should go to the dealer or a good independent shop which specializes in Benz

It has SBC brakes, which are are a little different than the ones on George’s 1992 Toyota Corolla

You pretty much need a pro-level scanner to do anything on the brake system, ESPECIALLY if it involves the brake fluid in any way


Nope, my grandmother bought it new in 1941 from our local Studebaker Cadillac dealer. She chose the $1120 two tone Landcruiser Commander over the $1200 Cadillac 62. Both car had about the same amount of room but the lighter Studebaker was a much better car for a woman.

The steering was lighter, it had hill holder (we lived in the hills) and Vacuum assisted shift it handled much better (the caddy wallowed on twisty bumpy roads) and the Stude got much better gas mileage. With the two tone spear down the side, I thought is was much better looking car. The cars springs ran in oil or grease filled boxes.

She kept it14 years, almost unheard of longevity for a car that was the family’s only transportation. She did not do much short trip driving, any place in town she preferred to walk. She was a hair dresser with a shop in her own home and the grocery store, butcher and butter and egg man as well as milkman delivered for free. We lived about 65 miles from Buffalo. She drove there to shop but all the store were right in downtown and she never carried any packages. Downtown Merchants delivery trucks delivered them to her door for free. We also got mail twice a day and 3 times on Saturday. We had some conveniences then that have long disappeared.

It had 160,000 mile on it when she sold it to my stepfather who destroyed it in short order, like every other car he owned. Mostof the mileage was from trips to the Eatern Shore of Maryland or florida. I remember sitting in the back seat and seeing the speedometer sitting on 90 mph on the narrow two lanes of the day.it had very comfortable chair height seats with a padded and wide center armrest and a laprobe cord on the front seat back. She also had light blue fitted luggage made for the trunk.

I looked a long time for a nice example of this car when I was in my 50s and 60s but I am no longer in the market.

Oh yes, the styling of the 40/41 Studebakers was very attractive. Plus the Commander had a larger engine than the Champion.
I would like one in my stable. The one I really want is a 51 Land Cruiser, first year of the V8 and suicide doors.

Ah, but I am dreaming.

I was wondering the same thing and also whether the E brake worked?

But then considering the age and usage of the car, an owner who continues to drive it with “mushy brakes” and the extreme importance of brakes, I’d start with the assumption that the entire system is suspect and prone to failure until proven otherwise.

i.e. If you have water in the master cylinder or it’s worn out, it’s a safe bet that the water has contaminated the entire system and/or the rest of the components are nearing the end of their life too

I would think that if the driver noticed the brakes were spongy and had a hill to go down as soon as they left the garage they don’t drive better than the average bear . :thinking:


Well it has been three days, the OP hasn’t noticed multiple replies.

How do you know the OP has not been reading the email replies? There is no reason to engage in conversation with people who are unfamiliar with this vehicle; “have it towed to a brake shop”. That is inevitable but do tell us what the hydraulic failure on your Mercedes involved.

Just curious what the important differences are, esp the ones that affect the proper diagnosis? & what does SBC mean?

SBC = ‘Sensotronic Brake Control’, German for ‘Crazy Expensive and Complicated’!