user 69696969

How do I know if mine is 330mm or 350mm? I rotated the tires and dont recall anything slotted, so I assume its a regular rotor in the rear.

I will research places but anything auto seems good, but any good deals on brakes. I dont remember the brakes being close to done, but the light came on so one of them is low or the sensor is broken.

marc hanna

You can measure the diameter with a tape measure. Yours may or may not be slotted; the main thing is making sure you have the right style: vented or solid.

user 69696969

whats the difference? why 330 or 350? My wife has the car. I am trying to look it up for pricing.

I have a 2008 r350 4wd standard wheels. I can't find why its 1 or the other. I see now about the rotors. When I read it the first time I was thinking of the rotors that are slotted. I now understand its whether the rotor is a solid disc or has the air gap in the center. like 2 discs put together with a space. I don't recall either way on venting.

josworth

This is a common theme with European manufacturers. They will use various brake set-ups within the same model making it kind of tricky to order parts without knowing the exact specs. My previous Jaguar was the same way. BMW's too.

I have read through this thread with great interest. BUT... based on the fact that Mercedes did a full brake job with new rotors, when the car was with the previous owner, at 46,000 miles; I will be using the Mercedes OEM parts when we need to do them.. Yes I said when...
Her R has over 100k on it now and still hasn't needed brakes. No vibration either.. just tons of dust as usual... I have not seen an OEM brake set up last this long and stay smooth ... Very impressed.

marc hanna

Vented rotors are when they have the 2 discs with a space as you say. Slotted is when they have the visible radial or angles grooves on the face. The difference between 330 or 350 is 20mm - more than 3/4". You need to know which type of rotor you have because they might not fit with your calliper. The vented rotors are thicker than the solid and therefore the calliper may not open or close enough with the wrong one. A rotor that's too large in diameter may rub on the calliper or one that is too small might result in the pads hanging of the edge.

user 69696969

Jos answered it, to the extent I needed. I am not asking the difference in 330mm and 350mm. That is simple. The larger question was the difference in vehicles that 330 and 350 were used with. Meaning if the 2008 320 used 330 or the 350 used 350 or 350 was for the 4matic and 330 was for rwd. and the same for vented or solid.

I guess its another reason mb does what they do to keep people coming back to the dealership. I am honestly not 100% sure this isn't just a censer issue because one of the mail reasons I did the last oil change and tire rotation was to inspect. Of course it was my first time with the lug BOLTS so the only thing I can think is maybe that first tire I removed I didnt check the back or inside pad on the rotor. I will review it this weekend.

Thanks as always

marc hanna

I suspect that the diameters coincide with whether or not they are vented or solid.

The reason why MB chose one or the other, I think, is just an option. Most 7-passenger MBs with rear airbags came with the vented rotors because it is more of a heavy-duty setup, and also a more expensive setup - at least this was the case in Canada.

marc hanna

I just looked at the rotor options available, and it appears that all rear rotors are 330mm whether vented or not. The front rotors are all vented, I didn't see any solid options. They appear to have a 330 or 350mm option, but according to Centric Brakes they are interchangeable.

marc hanna

Okay - one more post - it got me wondering, so I took some measurements. I have 330mm rotors on the front, and based on that, in order to put 350's on I would need 10mm clearance between the calliper/bracket and the rotor OD - which I do not. I just used a 10mm allen key to see if it would fit in the gap, but it is shy by about 1 - 2mm.

turbocad6

I'm fairly sure that the cars that have rear solid rotors use 330mm front rotors, while the cars that use the vented rear rotors use the 350mm fronts. they are not interchangeable without swapping out the calipers as well.

marc hanna

I've got vented front and rear. 330mm on the front.

turbocad6

I was fairly sure but now you've shown me otherwise. back when I was researching the brakes on my r500 that was what I came up with as the 2 different possible configurations for 06 at least, but I guess mercedes hasn't been so consistent with what they use on these cars so it's probably best to identify exactly what is on each individual car to be sure. as an example my r500 was supposed to have 350mm fronts and vented rears but it was an early model and winded up having solid rears and 330mm fronts like an r350

josworth

Like I said.... LOL.... Mercedes isn't the only one that does this...

Need to physically check what is there before ordering.

The minute you think there is a pattern, someone has a differing setup...

I'm servicing ours Saturday so I will inspect them, but this may be the first used car I have ever had that hasn't needed a brake service while I've had it.... Since it probably is only going to be with us for another year or so.

mercedesking

Thank you

josworth

102,000 miles and it still doesn't need brakes... or ball joints..... or any hoses.....

I know the 2006 gets a bad rap but seriously... every time I crawl around this almost 10 year old rust belt car, it just amazes me....

I do have an issue to fix.... a cd got stuck and won't eject from the player... Oh nooooo, she has to listen to an i-pod or the radio until I can get around to it.

I know, I'm jinxing myself... but despite the funky looks, I really have grown to love this silly thing.

Back on topic...

When choosing brakes I would seriously consider using the OEM parts based on how well they have worn on ours.

user 69696969

So for the record. It stopped raining long enough for me to check it out. Vented from 330 and solid rear. 2008 4matic r350 rear leveling only.

So there is that. I havent looked to far into the brakes themselves. They still seem ok from what I can see, but that doesnt include the inside pad. I also have not seen a mb full thick new pad. From the 30-40 brakes I have done I would say the pads look some where between 40 to 60 percent.

I read the op said one sensor was on the front pass and clear to see was tripped. So is that the only one? Not sure I read his discovery of the rear. Is it criss cross or both pass or just the front.

I am going to start pricing each part. I will take oem into consideration. I understand your point jeff, but I am not putting them into a car with low miles. At 104k I am hoping to get 60k before needing to make a vehicle decision. If its trouble free and in good shape more or less if needed. I will try and determine mileage per price. I like the idea of buying new rotors and getting the old ones cut. If I needed to do the brakes again I will only need to buy pads.

So I will do some research and reread the op, but I am trying to first develope a part list. Needed and recommended.

Rotors, pads sensors are all musts. In recent jobs the metal parts shims or whatever they are called came with the pads. Even some grease. The last 2 times I purchased them separately and had to return.

What eles should be considered to replace. I am set one flushing/bleeding I open and bleed the fluid close to the calipers. I wouldnt say I replace it all but I try and bleed out some and wait to replace until I finish.

marc hanna

You may want to inspect the brake flex lines on the front around the steering knuckle. There may be some chaffing or splitting of the outer casing and therefore you may want to replace them too. Also a good idea to buy the locating screws for the rotors because sometimes they get seized and you might have to drill them out. They're not critical, but they keep the rotor from spinning on the hub when you're trying to align the wheel stud holes. They're a softer metal so the heads often strip or they might be missing altogether.

user 69696969

Will do. Its gonna be a few weeks. I have a full plate.

efzauner

BTW MB star system says to replace the self locking caliper bolts...
Anyone do this? I just use locktite.. would be good to investigate this.
But in my 40 years of car maintenance I have never put new bolts, nor have I had a set of calipers get loose...

efzauner

and for brake disk/pad wear and life. It will depend a lot on the type of driving you do.
My previous 2008 fronts where still good when I sold it, they had over 120K km on them.
The rears I changed at 160Km. I did mainly highway driving.
Yet my recently acquired 2011 has only 40K km and rears need replacing soon. I know it was a city car.

user 69696969

Can anyone help me estimate pad depth? I cant see the inside pad, but the outside pads all appear to have enough left. They have not gotten to the full pad yet. Meaning the pads are made with the edges graded or sloped. As the pad wears it works its way down and at some point the pad has been worn to where the whole pad is contacting the rotor. I can see what looks like 3/8 almost a quarter inch of pad. The sensor is tripped. I can see the rear pass one but not the front. Not sure if its time to replace.

marc hanna

It sounds like it's time to replace them. Often the inside pads wear out faster.

user 69696969

I am planning on doing it. Its just whether its all parts done next week, or slow purchase of parts and do in a month.

turbocad6

if you're going to replace the rotors anyway then I' say it's fine to start slowly collecting your parts and you should be able to get at least a month out of them after the sensor touches. I got over 2 months out of mine after the sensor triggered before they started to actually touch metal to metal and I do at least 60 city miles a day with abusive braking. if/when it does actually start to touch metal to metal believe me you'll know. also, if it does start to touch metal to metal then you really should stop driving it because first of all that metal dust is pretty nasty stuff and secondly at that point you start to run the risk of damaging a caliper... I drove mine for well over a month past metal to metal and yeah, that will do some damage, but until then you really can buy some time with it

user 69696969

That was my plan, now I am off to research.