This test review that was conducted by the German car magazine- Auto Zeitung. The original article has much more information about the review, but I will only summarize the conclusion. If you do speak German, then head over to their website and read the whole story. The new Mercedes E-class may have got the looks, but does it have what it takes to take on its fiercest competitor from Bavaria, and the Japanese luxury sedan. The E-class impressed the testers with its comfort, especially on long trips, but the BMW 550i and Lexus GS 450h were not far behind. The new and improved Hybrid technology works in the GS 450h better than in any other hybrid model, and of course the fuel efficiency has been improved too, but what the Lexus lacks over the Germans is that the Trunk volume; It has been decreases due to the Hybrid engine. The Lexus also failed to achieve what Mercedes and BMW did in the breaking category. The E-class, with its stronger engine, takes the Mercedes to the front until 100 km/h, but the 550i takes the lead when they hit the 200km/h mark. Both the E-class and 550i Automatic transmission work fast and without jerking, but when changing the gears down to overtake, the Mercedes transmission did act a bit hectic. The engineers at DaimlerChrysler have done great work to improving the E-class driving dynamics. The steering has also been improved over its predecessor and results in precision driving around curves. According to Auto Zeitung and their unavailable raw data, the E-class won the comparison test over the BMW 550i and Lexus GS 450h.
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george
New Cars

 

So here is the deal-
Without the anti-rattle (anti-wear) springs the brake shoes had worn at a slight angle. The rotors also had worn at an angle but not as significant as the pads.

When the anti-rattle springs are installed the outside face of the brake calipers are pulled towards the center of the rotor approx .025" This movement in effect trues up the caliper with the rotor making the pads (if they were new) parallel with the rotor.

Because the rotor and pads had developed a wear pattern when the springs were installed there existed a slight gap between certain portions of the rotor and pads. The first pedal application would take up this play but resulted in a soft pedal and excessive pedal travel.

Three choices A) Leave the springs off and live with the wear pattern with unknown outcome.
B) turn the rotors, install the springs, drive for several thousand miles until the pads conform to the rotors.
C) Put new rotors, pads and springs on.

I went with number "C" and installed new Brembo rotors and Mercedes pads.
The brakes are now 100% photos will hopefully upload.



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Hi 418Viper,
I'm not sure I follow this.

Quote: "Without the anti-rattle (anti-wear) springs the brake shoes had worn at a slight angle. The rotors also had worn at an angle but not as significant as the pads."

Anti-wear springs? Not heard them called that. What wear? The spring that we are referring to do not provide the anti rub (anti wear) effect. That is provided by the shim between the pad and piston, and the piston rubber seals.

The rotors had worn?
Absolutely normal (change rotors at approx every other pad change. Defined minimum rotor thickness) and in so doing throw up a rust area which causes new pads to not sit correctly, at least until the pad has worn a little which takes just a few stops to achieve.

That is the diagnosis I gave you.

Without the big anti rattle spring fitted the pads can rattle around and in addition loads are not applied to the pins holding the pads in place.
Although these pins have interference spring clips to hold them in place the loading from the spring also discourages the pins from backing out ...with potentially disastrous effect.

It appears that all is now OK and that the "fault" was created by the normal situation when new pads are fitted with old rotors.

Stuart

 

i believe the problem is the pads were wearing incorrectly because of the rattle clip missing thus causing a slight angle on the brake pad to the rotor surface. now when you put on the spring the pad is now postioned correctly or the way it should be against the rotors, but the pads are not seated correctly against the rotor causing the pedal to feel the way it does.the tech working on your car probably cant look at the pads and determine they are wearing improperly just by looking at them, but if he knew the whole story then he probably wouldnt have tried to sell you a brake bleed, and he would have determined that the spring was not on there and the pads are worn incorrecly thus not fully touching the rotor as supposed to, causing a soft pedal feel.

 

That is exactly what occurred. I don't fault the tech for the brake bleed. However when they could not fix the problem they told me I needed a new master cylinder and quoted me a price for 502$. Imagine if they had put a new MC on only to find the repair did not correct the problem.

Fixing a problem by process of elimination is a costly process. This forum has been so helpful I posted the follow up for everyone's info. Intend to talk to the dealership about the issue also.

 

Bob done.

Tick!!

 

anti rattle springs can in no way cause brake failure...without sabatoge involved