mandkole

What are you higher mileage folks getting out of the factory pads intervals? It seems that the rears are set up a little thinner than the fronts and have some fairly strong bias (causing them to wear out quicker than front). After my visit to the dealer, I'm told that I'm down to 3mm in rear.

After paying for lessons in the dealer's maintenance pricing schedules ($150 for an air filter/$165 for a fuel filter/$35 for a tire rotation that should have been done when the wheels were off for a brake inspection), I'm trying to decide if I will do these myself and how much longer I'll have to make decision...

BeanCounter

I replaced the rear pads at 25,000 miles and the fronts at 33,000. My driving is a combination of city and highway. In general, I am a pretty light braker so I am surprised when I hear longer intervals for others on this forum. My understanding on the rear's wearing out quicker is the bias that you mentioned and also that the stability control automatically engages the rear brakes periodically to"keep things under control". This is my first Mercedes and the one thing I do notice is that the cruise control keeps the car at a steady pace regardless of whether you are going down hill or not. As such, it is clearly engaging the brakes to do this and my understanding is that it is the rear brakes. My rotors were fine when I got my new pads so it should not be much more than $250 per axle at the dealer. Hope this helps.....

bselph

I have 59K on a 2008 Gl320cdi and have never touched the brakes since 0 miles. Last service the techs said I was still in specs.

hcetzneb

Ive seen pads go at 25k and up to 60k.. It all depends on the driver and road conditions
but mostly the driver. Also ESP/ABR plays a large part in the pad life, your ESP/ABR system applies the pads to correct over and under steer and also controls tractions and tire spin it uses the brakes to regulate and also to reduces engine torque.

Ive seen the rears go on a gl550 at 15k and i knew the cust he drove like he was on a race track all the time

MomsBenz

I have 22K on my GL and have not touched the brakes. My last service (C) at 20K I was told the fronts were 70% and the rears 60%.

BlownV8

66K on mine but will need to be replaced very soon.

mandkole

Thanks for the notes-- sounds like its 'all of the above' when it comes to reasons. Its good to hear that the highway guys are getting good life from theirs and the city guys are getting less.

Its still taking me time to get used to the brake feel. They barely come on at light pedal ,and just a little more, the assist comes in hard. Much more difficult to modulate them compared to the recent cars we've had.

googv

I was also under the impression that cruise control uses brakes to keep car speed steady but it is not true.

It throttles the engine to keep the same speed and does not use brakes.

asg

Have 27k on ours and have not done the brakes yet, but almost ready for tires.

anb957

googv:

It definitely uses the brakes with cruise.
Go down a steep hill at 40 MPH and set the cruise.
Then toggle the speed down and it will vigorously slow the vehicle (has to be using brakes)

StevethePilot

Even on my 320CDI it uses the brakes. Engine throttle's hardly ever enough to overcome a steep hill. And I remember the very first time I found out about this, when I rented an early SLK (many moons ago) to take the wife to Sedona for our anniversary. On the drive home, the little car kept its speed perfectly on the downhill portions of I-17, while everyone around us were braking, then speeding up, then braking, then speeding up ... so it is hardly new technology, which makes me wonder why nobody else does this?

Anyway, it does, unquestionably, use the brakes. I've had my foot follow the brake pedal down when it's doing it.

43221B

And, your brake lights will come on when the cruise control brakes the car... I wonder what the mechanical differences are between the GLs equipped with distronic and without it.

BeanCounter

Your absolutely right and I did that once in a construction zone where the speed limit went from 70 to 55. I toggled down to 60 and it slowed down in about 2 seconds.

I am impressed with some of the mileage reports on the brakes. I am starting to wonder if my dealership was being totally honest with me when they told me I had "about 20 to 30 percent" left......

alx

i am at 35k miles on mine and i am at 50% or more both front and back...

googv

Hmmm....

I even read an article on how cruise control works and it specifically mentioned that it does not use brakes.

I need to re-read that article again and do more research on this.

Thanks for highlighting this.

Fourdiesel

googv -
Make certain the article specifically applies to diesels (as well as gassers). Gassers have a throttle plate that can be used to create energy losses and decelerate the vehicle. Diesels do not. A moderate amount of drag is created when the tires spin the engine when no fuel is being injected (diesel). If more deceleration is needed by the cruise function, the system applies the brakes (probably rear first to help with stability). Gassers need less help braking but it is probable that Mercedes does not use different brake programming for the two variants

Brocktoon

As a matter of fact, our Diesels are one of the few light diuty diesels that have a butterfly valve betwen the turbo and the intake that would serve the same function under deceleration as a throttle. If you have driven a light turbo diesel over in Europe, you will see that engine braking is near impossible, as the added revs just cause extra boost, and downshifting, without pressing the accelerator will cause the car to speed up and surge forward!

Fourdiesel

VW TDIs also have a butterfly valve in the intake line just before the intake manifold - BUT - it is used ONLY for anti shudder when the engine is switched off (and potentially in a runaway situation). I know in the VW it is NOT used to create engine braking. I do not think it is on the Mercedes GL diesel either.

Brocktoon

The link is dead, but I read about this effect in the mini manual for the engine that I reference in this thread a couple of years ago...

https://mbworld.org/forums/gl-class-...di-engine.html

lkchris

The easiest way to prove it to yourself is to do something like the 70->55 slowdown at night somewhere dark--you'll see the brake lights.

Fourdiesel

That assumes the cruise control energizes the brake lights when it energizes the brakes - not a trivial assumption especially if it is designed to apply only the rear brakes. If the brake pedal drops (and this would probably mean the front brakes are energized also), then the brake light MAY come on when the switch on the pedal arm closes. Otherwise it is doubtful.

robalo220

Ok in regards to the brakes. Yes the pedal does depress. I've felt it drop when cruise is on and going down a steep hill. The brake lights do come on as well. I have been towing a boat from Kentucky to Florida and back. Part of the trip is done in the dark. I was surprised to see the boat light up when the brake lights come on in this situation of downhill in the dark. That being said, if the break pedal is being depressed by some mechanism, I would guess that all 4 wheels are breaking at the same time. I Just turned 20K and had the ripoff second service which was an oil change for $300.00. They did inspections but did not report anything to me about brakes.

43221B

Agree on the brake lights coming on while using cruise. I tested it out a few weeks ago because I noticed my GL slowed so quickly using the cruise that I thought it would be dangerous if they did not, so I checked it out while I was on a pitch black rural road.

IridiumRoad

Not only does the cruise control apply the brakes, but if you are towing a trailer (and have the trailer brake controller connected per TSB with the Mercedes harness), it will also apply the trailer brakes.

mortenmol

the same with distronic, the pedal depresses (Which is quite weird the first time) and the brake lights come on