W166 GLE Brake Pedal Travel

[V6GBJ]

The brake pedal travel on my 2016 GLE seems excessive. It makes it difficult to set the seat so that it's comfortable for using the throttle and the brake pedal. I took it to my local Indy for a "quick look", this was because it's still under a used car warranty with MB so if there's a real issue it would need to go to the MB dealership which is much further from home. The Indy could find no real fault and the pads are not close to worn out. Does anyone else suffer this issue?

 

[Bellow]

Soft and spongy throughout the travel, or initially free unopposed motion followed by a solid pedal?

 

[Will]

I must admit, the pedal feel on my X166 is slightly less firm than you would expect.

Brakes functioning absolutely fine but it feels like it takes a bit more of an initial push than expected (compared to driving almost new cars daily).

The fluid was changed on mine a few months back, no discernible difference. Perhaps a characteristic of these vehicles (they are heavy beasts too of course). It stops fine, pads and discs all okay just feels a bit different to other MBs I have owned and driven.

Mine is a GL63 so will have different calipers etc than the OPs car, I expect the pedal feel will be down to the hydraulics/servo assistance side of things?

 

[V6GBJ]

Soft and spongy throughout the travel, or initially free unopposed motion followed by a solid pedal?

Thanks to you and Will for your replies. I can best describe the travel as soft when feathering the brakes but later solid after further pedal travel. Maybe it is a characteristic of a W166. The mechanic at my Indy did say that when changing the fluid on MLs and GLEs, they might find the pedal to be a bit soft and go back to check that the system is full.

 

[Bellow]

Thanks to you and Will for your replies. I can best describe the travel as soft when feathering the brakes but later solid after further pedal travel. Maybe it is a characteristic of a W166.

Brake 'feel' does vary from car to car but that it goes solid when 'stood' on suggests no great problem.

The mechanic at my Indy did say that when changing the fluid on MLs and GLEs, they might find the pedal to be a bit soft and go back to check that the system is full.

The focus should be less on 'full' and more on bleeding. Possibly there's a bit of air trapped in the system making it softer and increasing travel during the initial braking phase. Brakes to some extent are self-bleeding in that any air is always trying to rise and will usually find its way to the master cylinder and escape - washboard road surfaces help! Similarly, a locked wheel that activates ABS will often release any air trapped in the ABS unit. All bit red-neck but a combination of that and merciless bleeding finally sorted out my horrible feeling brakes (not MB).

 

[Will]

I wondered about slight runout on the discs, or slightly excessive end float on the wheel bearings, pushing the pads away so the first application takes a small amount of travel until they begin to clamp strongly.

No noticeable pulsation or any vibration on the brakes on mine though, but it’s the sort of thing I would also check if it concerned me

 

[Bellow]

I wondered about slight runout on the discs, or slightly excessive end float on the wheel bearings, pushing the pads away so the first application takes a small amount of travel until they begin to clamp strongly.

No noticeable pulsation or any vibration on the brakes on mine though, but it’s the sort of thing I would also check if it concerned me

Good points.
In the case of disc runout, either pulsing at the pedal or, the caliper just rides it out harmlessly. In the case of bearings - if after a period of driving (especially through bends) without having used the brakes for a while the first application sees a long pedal - but not the second - then 'pad knock-off' a definite possibility.

 

[V6GBJ]

Good points.
In the case of disc runout, either pulsing at the pedal or, the caliper just rides it out harmlessly. In the case of bearings - if after a period of driving (especially through bends) without having used the brakes for a while the first application sees a long pedal - but not the second - then 'pad knock-off' a definite possibility.

Thanks again guys. The car has done only 20K miles so i doubt (or hope) that it's not as serious as bearings, calipers, discs etc. I'll book it into the MB dealership before the used car warranty runs out in Dec.

 

[Bellow]

Thanks again guys. The car has done only 20K miles so i doubt (or hope) that it's not as serious as bearings, calipers, discs etc. I'll book it into the MB dealership before the used car warranty runs out in Dec.

By your description it doesn't sound like anything mechanical. A bubble of trapped air causing a bit of sponginess on light application seems to be all it is - nothing serious. It may well improve without you doing anything but drive it.