Disc wear E320 Auto

[Lexington]

Would welcome some advice re my 2005 E320 Auto. At my recent service I was told that the Discs would need replacing. Having only done 38,000miles this seems to me a low milage for this to be a problem. Pads I understand but, it seems the discs are too soft for the pads?

Would welcome others experiances/comments. If this is a problem who should I complain to to get a free replacement - my dealer or MB UK? Thanks.

 

[Bobby Dazzler]

It seems common place for MB dealers to recommend disc replacement whenever they change pads.

I suspect it's because they charge for labour on changing pads, and labour on changing discs. In reality the actual time taken for doing both at the same time is negligable, and so is a good way of boosting profit.

When I exclaimed at changing discs at close to 30,000 miles on the ML, a previous dealer I used said it's not unusual for disc changes in the teens on the ML, although they'd done them as low as 7,000 miles. Shocking for pads nevermind discs!!

Gut feel tells me that your discs probably aren't dangerously worn - or even in such a way that it would impair braking efficiency - just within the range where your dealer would recommend replacing.

Given it's your brakes though I'd get a trusted second opinion if you decide not to change the discs.

 

[Bobby Dazzler]

PS MBUK is probably your only option as they may be able to make a goodwill contribution. I doubt your dealer would entertain it - may give you a small discount if you're lucky, but not much more.

 

[Benzowner]

It has been said before on here somewhere, that since the demise of asbestos brake components, the compound in disc pads is now much harder so wear the discs out quicker. 38k miles does not seem low to me, on my E300 I was on the third set of front discs in 105k and probably getting towards the end as well, and as said, disc and pad change only really constitutes extra money for the discs as additional labout is minimal. Worth asking for a price for both from MB just to see, and queerie it if there are two sizeable labour elements.

 

[GeorgeA]

My C220 needed new rear discs at 27k miles, before the pads had worn down even. This was associated with a shudder thru the car when braking, which completely disappeared after replacement.

If I were you I would consider replacing them as the labour charge will be charged twice if you don't. As for getting a contribution from MB I think wear and tear items are excluded but good luck

 

[kth286]

If you know what you are talking about you could ask what the remaining thickness of the disc is.

There is a limit specified by Mercedes.

If you knew the figure you could even go down there armed with a micrometer and measure the thickness yourself.

Ask for the old discs back. How your know they are yours though I do not know.

As Mercedes cars are reputedly getting more reliable there is less warranty work for the dealer.

Hence they are trying to maximise each customer's spend.

 

[television]

I have heard it said that the min thickness is stamped on the center of the disc

 

[BlackC55]

Yes it is. It is on the "hub" of the disc.

 

[Lexington]

Thank everyone for the advice. I shall be out with the micrometer at the weekend if only to satisfy my own curiosity!

 

[grober]

When you renew the discs its recommended you fit new pads at the same time so it makes sense to do both at a routine pad change/service.---assuming they are worn down to the limit. Difference between new and "worn" is only a matter of 3mm. A quick check is if you can feel a distinct "lip" at the edge of the disc where the pad doesn't press on they are on their way out. Still worth checking with a micrometer tho as suggested. Remember also that with modern stability/ traction control systems the brakes may be constantly being applied by the electronics without the driver pressing the brake pedal. The ML is a classic example where its traction control system relies mainly on the brakes to work instead of locking/limited slip differentials hence the accelerated wear patterns.