vkapoormd

So I have had the opportunity to finally drive my SL 600 this weekend extensively (the car is temporarily down in San Diego at my parents place until i move back down to So Cal in a couple of months). One thing i noticed today that as i came to a stop, the brakes squeaked a moderate amount, and probably half the time. I found it rather annoying, as the car only has 1500 miles on it (i bought it with 1260, but didn't really appreciate it that much as most of the initial driving was top up due to weather). The car itself stops fine and there is no grinding or anything, but it is really irritating. Is this just another quality control problem, or is there something that needs to be adjusted? any thoughts would be appreciated.

WIldcat465

I have the same problem with my CL. I'm taking in to get checked.

pilot20

Of the 4 MBs I've had 2 have had squeaky brakes. On the SL the dealer said it was due to brake dust and he cleaned that off the brake pads. We all know how long that "solution" lasted, right? It lessened over time but never completely went away. It was embarrassing to come to a stop light and have this expensive car make a racket that other drivers could hear. Over time I learned to live with it, though I was unhappy that MB could make a technologically "advanced" car and yet not figure out how to do what 99% of carmakers seemed to effortlessly accomplish.

LovinMercedes

My brakes do not make any noise.

I guess I just got lucky.

NeilC123

After having seen a lot of the other posts i'm not sure the lack of squeaky brakes is a luck thing. I have to say i find it shocking the horror stories for very high priced cars - what is the point of paying over £100,000 if it ends up in the garage - the 2sec wow factor as u speed past is definately not worth that. And then on top of that we have a SL recall - why put them out if they are going to recall them - whatever happened to the rigurous MB testing that goes on. I have to say I am more inclined to go for a bog standard SLK/SL and then barabusize it or Carlsonise it - at least that way it won't make me cry so much if anything goes wrong and also it will be individual as well. That is of course until some other make does a sexy folding hard top (and i don't mean peogeut, renault or Vauxhall - i mean a decent make).

tiggerfink

None my Mercedes squeak. The Buick rental is driving me crazy with its squeaky breaks.

LovinMercedes

I hear ya.

Florida Chris

Have the dealer or a brake shop spray the back of the pads with anti squeal compound. CRC makes a product called "Disk Brake Quiet" that works quite well, you can get it at any auto parts store.. I have used it on the back of my noisy (former) Porsche and my Minicooper. Works like a charm.

vkapoormd

does anyone thing this maybe related to excess air in the hydraulic system? i did a forum search on the squeaky brake topic, and there are some prior comments about air being need to let out of the brake lines- of course this was on an 2003 E class and i don't know what the difference is in the 2005 SL versus that care. In any event, i am taking it back to the dealer this week....

RadSteve

Air in the hydraulic lines would be a very baaaaad thing, air being compressible, you would lose effectiveness of the hydraulic system (but aren't SL brakes now electronic servo activated rather than hydraulic anyway?) Squeaks should be a local friction problem resulting in unwanted vibration that is audible.

Florida Chris

Your squeaking has nothing to do with air in the lines. Your brake pedal would feel soft if you needed bleeding.

vkapoormd

Well thanks-i was concerned about that...in any event, I got around to calling the service dept at my dealership in LA- and the service advisor felt that there might be some rust on the rotors (as the car was on the lot for a couple of months with some rain) or the pads might be worn out prematurely. In any event, they said they would replace both under warranty if needed. Furthermore, i was pleasantly surprised after calling my salesman about the issue, and withing a couple of hours, the service manager called me and said they would pick up the car from my house and drop of a loaner. Part of this probably stems from the fact that they hope to get more business from me in the future (and after this, they probably will). So i will keep everyone posted. Thanks for all the recommendations.

RadSteve

Let us know if they fix the squeak. Thanks

Scotsman

Nup, my brakes are fine and the car's now done around 5000 miles.

blueSL

It's certainly the case that air in the hydraulic system would be bad news, just as it would be for any other car. The SL uses conventional high pressure braking circuits and brake calipers. Where it's different is that the braking force depends on the position of the brake pedal and how quickly it is being pressed rather than the pressure applied to the pedal. That makes it easy for the car's other electronic systems to adjust braking to implement ABS, Brake Assist, the pad drying function, SBC hold and so on.

blueSL

Not true. The brake pedal is normally not connected directly to the braking circuit so there's no indication through the pedal that the brakes need bleeding. The brake pedal resistance you feel is completely artificial being produced by a two stage spring and a pyramid shaped rubber bung, all designed to give the progressive pedal resistance we are used to.

One of the consequences is that you do not feel the pulsing through the pedal when the ABS is active.

It's only in the SBC limp home mode that the pedal is connected to the braking circuit to provide pretty marginal brake effect. You would know all about that, not least because of the red displays on the dash...

xtianpel

Hi Blue,

I'm taking my car to the dealer tomorrow for the A service. My brakes are doing the same thing, which I will mention, but I'm sure they will tell me that I need new brakes. Last time I took it in they told me that either the front or the back were at 35% and the others at 40%. I just cannot believe that. The car has 4900 miles on it, but it's already 1 year old so the A service should be covered. Could I possibly need new brakes so soon? What intelligent question can I ask so that they don't try to push something on me that I don't need? If I do need it, can I ask them to see something that would indicate that I need it? Sorry, I'm an idiot when it comes to this. I do live on a hill and there are 7 stop signs between my house and the boulevard so I know I wear brakes more often than other people. In your experience, what should I be expecting as normal wear for my situation?

Thank you.

P.S.: Anyone else please feel free to comment as well.

blueSL

Interesting that you are taking your car in for an A service. Is that what the ASSYST display is telling you? On my older car, it timed out after two years and I could have driven about 11600 miles.

First, look at the impact of those 7 stops which is quite significant.

When you brake, the energy of the moving car is converted into heat in the brakes; if you are on a slope, the brakes are working against gravity in addition and have to work harder. To a first approximation, the energy put into the brakes is equal to the change of the energy of the car, kinetic and potential, across the braking cycle.

So, if you are braking from 30mph to 0 and the car is falling 100 feet while you're doing it, how much harder are the brakes working compared to what they'd be doing on a level road?

This is 1 + 2gh/(v**2).

g is 9.81 metres/sec**2
h is 100 feet or 30.5 metres.
v is 30 mph = 13.4 metres / second

Plug in the values and you get 4.33! That means they are working more than 4 times as hard as they would on the level.

So, you are right not to discount the effect of those 7 stops. Even so, only you know how much of your total driving this represents. I'd be surprised if 4900 miles would wear the pads through for essentially normal driving. That said, they will look at the wear and want to replace the pads if it doesn't look like they will see you through to the next service.

If I were you, I would ask to see the pads removed from the car (if that is what they say is needed) and you can judge the thickness of the remaining pad material. I would be very suspicious if they said you needed new discs/rotors.

NeilC123

Trust BLueSL to provide the maths/physics...it could just be that Mercedes materials are not what they used to be.....I had to replace my brake discs after 20,000 and costed me £200 - so in the end of the day the more they can find wrong with it - the more they can charge....

xtianpel

Wow BlueSL! I'm in awe.

Thank you so much for taking the time to explain it all. What you're saying makes perfect sense. The 7 stops are more on the flat side. There's only one on the hill side, so it's not as bad as it could be. I will absolutely ask to see the parts they replace if they tell me it needs brakes. I suppose the % means % of life left on the brakes. I don't know how many mm that would be but I assume it should be pretty obvious once I see my existing pads and a set of new ones. Are there any pictures out there of what worn pads are supposed to look like? As I've said before, I never dealt with this stuff before so everything is new to me. I am pretty tired of the dealers ripping me off and I want to become a more informed consumer.

Thank you BlueSL one more time.

blueSL

I expect the pads are just industry standard. They may have an MB logo stamped on them but they will be like millions of others produced by a third party vendor. We don't know yet whether new pads will be needed, I think 5k miles is not alot to get out of one set.

It does show how punishing it can be to drive a car down a mountain pass. Here in there's a fab pass in the Alps called the Stelvio, twists and turns all the way down, it really takes it out of your brakes.

xtianpel

I'll let you guys know what happens once I visit the dealer.

Thanks, C.

PA55AMG

If you have the typical slow speed squeal (coming up to a stop sign), you can use a pressure washer and blast the excess brake dust out from the calipers. This has helped me many times.


Another thing that can help, is to round the sharp edges off the pads. This is obviously a more involved process, but this is what the dealers do all the time with the "my brakes squeal" service orders.

xtianpel

Thank you so much for the info!

vkapoormd

So, the dealer said my front rotors were rusted; they replaced both of those and the pads as well...happy to say the squeak is gone!!! (well for now, i am keeping my fingers crossed).