Hello, is it possible to replace the front brake solid rotors with vented rotors? I have a 2016 E350 4Matic wagon with Luxury trim. It's not a Sport so I'd like to be sure the upgraded rotors will fit. The solid front rotors have warped and I'm wondering if vented rotors would remain cooler and not warp. I'd likely get non-Mercedes brand rotors, such as Zimmermann. Thanks.

 

are the rotors actually warped, has someone measured the runout with a dial gauge? pulsing brakes are generally a function of uneven pad deposits on the rotor surfaces. number one cause of this is braking hard, then leaving the brakes clamped hard at a stop. Or rotors that are worn too thin.

'vented' rotors are almost entirely cosmetic. They are interchangable between the E350 'sport' and 'luxury' packages.

 

I've had good luck with the Zimmerman's, the coating keeps them looking nice, I've removed the slotted rotors from my last three Benz's due to brake dust accumulating in the holes and ruining the rotors, granted all three cars had organic and semi-metallic pads as original, I just put the solid Zimmerman's and Akebono ceramics on my sport and have been happy with them, I just drove to Arizona and back, a 4,000 mile trip and they were great, I don't miss the black dust on the wheels . they absolutely don't stop as fast as before, I believe that's totally the pads.

 

+1 ... did the same swap and it's been smoothly braking for 30k miles

 

I recently renewed all my brakes around and had the same hitch to upgrade my solid rotors to sporty looking disks.

There are many pros and cons tainted by misleading advertisement...

The higher maintenance we can deal with but what did it for me was not downgrading the overall braking surface with swiss cheese holes.

> To help curb your warping issue... you must silicone-lube the caliper sliding pins.

> In addition the calipers are prevented from sliding effectively by the use of wrong calipers springs from factory.
This will be evidenced by outer pad being much thicker than worned out piston inner side pad. Have a look!

> Lastly be sure to bleed air bubles out of at least the rear wheels preferably all four corners with fresh DOT-4.

Then you'll have best strong brakes ever after 1 to 500Miles bedding...

 

Thanks for the tips. I have not yet measured my run-out but I will. I believe the inner and outer pads are worn the same but I'll know more once I remove them. I'm sticking with semi-metallic pads because I'm afraid of the slower stopping power / warm up time of ceramic. Thus it sounds like solid rotors are better so the dust doesn't clog the vent holes. I will be replacing all the brake fluid, bleeding carefully with my Motive air pressure bleeder.

From my other thread, does anyone have the official Mercedes procedure for changing front and rear pads with floating calipers (piston on one side)? I'd like to be sure I get all the torques and steps correct since it's my first time doing brakes on this car. Thanks.

 

note the primary ventilation on the fronts is the space between the disks, this works centrifugally, sucking air in near the hub of the rotor, and exiting the outside rim of the rotor., this nearly doubles the rate of cooling versus a solid rotor.

 

Not to correct you - the "solid" FRONT rotors still have vanes in the core of the rim. The holes on the faces are for nothing more than out-gassing. Specifically NOT cooling of the rotor surface, it is so that gas does not build up under the pad while applying braking force. Cooling nor anti warping is not an intended function of a cross drilled (or slotted) rotor.

The rear rotors are solid disks.

 

yeah, I was referring to fronts only. backs don't do nearly as much work, and aren't really subject to heat fade unless you're really abusing things. Thats the first I've heard the slots are for pad outgassing rather than rotor cooling, but that makes sense.

 

I have Zimmerman rotors and I really like them. Originally got them because they were cheaper than Genuine Mercedes but now it looks like they are more. Got all my brake parts from FCP for the lifetime warranty. Glad I did since this was 5yrs ago and it will be time to replace them soon.

I went with Ferodo semi-metallic front pads and ATE semi-metallic rear pads since they were listed as OE. When I removed the old pads they were all genuine Mercedes and it did look like they were also stamped with those manufacturers markings. The car stops great and have no complaints other than the rims get filthy quick. Just one short trip and the rims have brake dust all over them.

The front rotors have the holes and they seem to stay open. Ill run a drill bit through the holes to check and never noticed one totally clogged.

I noticed the Brembo website has diagrams with all the measurements for the rotors they carry to check if they are the correct size.

 

Thanks for the input. So it sounds like vented rotors won't help cool the rotors, and keeping rotors cool might not help to reduce warping. I thought I read that front rotor warp was a common problem. I've used Zimmermann rotors on other (slower) cars and they've performed well for years. I'll install the Zimmermann solid front rotors on the E350 and see how it works. Of course, I got them from FCP so I'll use the lifetime warranty.

 

Solid front rotors? I thought they were vented, meaning they have the vanes inside? Drilled rotors have the holes in them.

The rears on my W204 are solid, no vanes. Also no holes in them. The fronts are vented and are also drilled which I believe is due to having the sports suspension option.

For installing the pads I had originally greased everything until I came across some info specifically about the Mercedes brakes. I went and cleaned everything up after seeing it. The only things I used grease on is the guide sleeves on the front calipers and then under the metal anti-rattle springs prior to putting them on. Yours may not have these metal anti-rattle springs. Im not sure which brakes you have.

Heres the boots on the calipers im referring to:




Heres the specs I use on what to grease:

 

From Frictionmaster:

In the early days of racing, drilled rotors were an effective way of venting the layer of gas and dust that inevitably builds up between asbestos brake pads and the rotor under repeated, hard braking. However, as technology and brake pad materials have progressed, outgassing has become less and less of an issue. These days, while they still look great and perform well, the drill holes are more for aesthetic reasons than anything else.

 

I will simply add that this has long been known (published decades back) in the 911 world. It's a common misperception what the holes are for. Likewise common is the "warping" of rotors which happens far less often than irregular pad deposits on rotors causing the dreaded pulse. Mic'ing the runout demonstrates this many times over.

Fwiw, I fully intended to replace my front rotors along with my pads since I had been tolerating mild pulsing (under heavier braking only) for a many thousand miles now. But when I looked at the rotors' wear --or lack of it!-- I figured I'd roll the dice and just replace with Akebonos, which I've used on many cars/SUVs in the past and love em for their feel. Sure less dust is nice, but I personally hate the "touchy bite" of most factory brake pedals, the E350 included. The Akebonos have always provided better, more linear braking, which to me is the definition of better feel (as opposed to that over-boosted feeling from too much initial bite) ...sorry, that was a digression. Bottom line: replaced just the pads on the original 122k miles rotors and the pulsing is mostly gone. Yeah, I'm sure it would have been perfectly gone had I replaced the rotors with the Zimms, but I was doing a "test" of sorts, lol! Anyone feeling the pulse I'd suggest doing both the Akebonos and Zimms. IMO.

Fwiw, a "solid" rotor is a term that should not be confused with a cross-drilled/slotted rotor. A "solid" rotor is a differentiation from a "vented" rotor which are the double-wide suckers with cooling vanes in between. The greater mass offers higher thermal capacity than a "solid single" rotor, and the vanes are absolutely there for cooling that mass. All of which reduces brake fade under duress, like track use. But for street use, keeping braking components cooler not only obviates any brake fade, but helps pads/rotors last longer, sometimes significantly longer. I cannot tell you how freakishly quickly our old Odyssey used to digest front pads ...just stupid/crappy design, IMO.

Edward

 

I will be replacing the pads and rotors as a set. When I first bought my W204 the rotors were in horrible condition more so the fronts. Deep grooves and ridges, think I remember seeing hairline cracks all over them. Then the pads were full of grooves. It had all genuine Mercedes parts installed which was great to see, makes me believe the car was well cared for.

Now I have around 29,000 miles on the Zimmerman rotors, Ferodo front pads and ATE rear pads and really impressed with how they are wearing. I am always working on the car doing something so whenever I have the wheels off I have a look at the brakes and give them a quick cleaning with brake cleaner. For the most part the holes in the rotors stay clean, cant remember ever having any clogged up.

As for replacing the rotors mine are developing a lip around the outside so it looks like the rotors are wearing down at least on the front, the rears dont seem to have a lip. The pads themselves still have alot of thickness on them. I doubt the rotors would last through another set of brake pads if i didnt replace them. I will say that I drive normal. I recently took these photos while spraying fluid film everywhere to get ready for winter weather.

 

Live free or.....
use a little NE ingenuity in the future. The pad material built up on the rotor can be sanded down with noticeable effect. The aforementioned Odyssey (same gen?) front rotors (vented) were power-sanded several times. Pulsing either eliminated or significantly reduced. Pads not always changed. Also sanded my E's fronts once when changing pads. Similar improvement. YMMV.

Q to the Panel: Would weight reduction (on a sports car) be an additional reason for drilled rotors? inquiring minds....

 

Speaking of rotors, does anyone know the minimum manufacturer recommended thickness of Mercedes solid faced front rotors? I hope to find it stamped on the rotor but that info might be rusted over.
Does anyone have the official Mercedes procedure for replacing pads and rotors on floating front/rear calipers?

Thanks TimC300 for the official Mercedes info. I like to do work by the book.
When I said "solid rotors", I meant "solid faced, not drilled or slotted" with interior vanes. Sorry for the confusion.
I will check my rotors with my Mitutoyo dial indicator before replacing them. I feel pulsation under moderate to hard braking.

 

My Zimmerman rotors have the thickness stamped on them.

 

Doubtful. I don't think the marginal amount of material removed for holes would have any effect on the unsprung weight of the suspension. However, I could be wrong. I have some new, uninstalled cross-drilled Genuine Mercedes front rotors I may weigh tomorrow, but it may be hard to find a solid-face rotor of the same size to compare with.

For anyone considering slotted rotors, I think you will be unhappy once they start to wear. They make the brake feeling very rough.

 

Slotted and drilled rotors warp easier than solid, as there is less metal.

If you are having repeated issues with warped rotors even after replacement, check for runout on the hubs, and ensure slide pins are free, check rear brakes are not stuck putting more brake pressure on the front. Also old brake hoses can cause uneven brake pressure causing warpage. Last check Master cylinder and ABS, Speed sensors, and fluid condition, as well as yaw sensor alignment. All of these with a subtle fault can cause rotor warpage over time. But most common is; stuck caliper pin/pins, deteriorated hoses from the inside, and hub with abnormal runout due to rust or impact
. At least these are the most common repairs for repeated warped rotors in my shop.

 

vented will warp Even worse! You want slotted not vented. Yes slotted costs twice as much as vented but they PERFORM

 

Thank you Rick for all these precious pointers.

I think weve overlooked the adjustable loose front wheel bearings! It makes the loose wheel and disk shake.

The calipers sliders are mounted on the spindle and the disk is connected to hub by 2x ADJUSTABLE bearings.

• Driver side bearings gets looser
• Pass. side bearings gets tighter

It's a Mercedes...

 

Not true, just the opposite.

I was warned by colleagues to NOT try to help, or give opinion, too many desktop experts. Oh there are some brilliant minds here, and I thrived on helping. but if some of you would rather enjoy your folly. Knock yourself out.

 

they look fast with skinny tires on bent rims...

 

Agreed.