does the ediff/DSC also utilize the rear brakes.

 

The DSC can actuate any/all the brakes through the ABS system.

I don't see any connections between the ediff and the brakes. From the description of operation it looks to me like the ediff will just lock the rear axle. From the service manual:

The basic construction of the electronic differential is similar to the open differential. However, the electronic differential also
has the following:

 Two additional planet gears in the differential case, to cater for the higher torque of the SC engine.
 A multi-plate clutch and actuator assembly installed on the LH (left-hand) sun gear.
 A motor and reduction gearbox, attached to the cover.
 A temperature sensor installed in the cover.
The DLM (differential locking module) operates the motor of the electronic differential under the control of the ADCM
(adaptive damping control module).

 

David I am wondering if the system applies rear brakes when ediff tries to control the car. I know the throttle is cut.

If so it would add to disproportionate wear....on this drifting champion.

 

From what I see from reading about how the ediff operates, it just locks up the differential under hard acceleration. Without positraction or some type of locking rear end one tire will spin under hard acceleration. Some cars will stop one tire from spinning with the ABS and/or traction control by applying the brakes. Less expensive but not as efficient as locking the differential.

I don't see any direct connection between the ediff and DSC. If the DSC thinks the brakes need to be applied to stabilize the car it will do that. If the ediff wants to lock up, it will lock up independent of the DSC.

That being said, if the ediff is locked up from hard acceleration, it is more likely that the DSC will apply the brakes to keep the car stable.

 

So we can triangulate a little bit more from that point.

If I completely turn off the DSC (not easy to do) and drive slightly spirited in sport mode.
The car will break traction all the time.

So my suspicion is that the rear brakes are being used lot more than we realize- if we drive spirited and have the traction control on, particularly on so-so tires.

 

That is a possibility. If the car is driven a LOT with the traction control and DSC taking over to keep the car under control then I would say all bets are off for when anything is going to wear out or break.

If the car is driven normally most of the time. the front brakes should wear faster than the rear brakes. If the rear brakes are wearing faster then there is a problem. Since that is not the case on most cars I don't believe there is a design problem. So the most likely culprits are assembly/adjustment, brake pad material, or possibility driving style.

 

Well, I can make two contributions to this discussion. 1) My 07 XK always exhibits more brake dust on the rear wheels (always) than on the front. I am a fairy conservative but not grandmotherly driver so I know that it is not my driving style that causes this. 2) when I mentioned this to the tech at my dealership after replacing the rear pads he told me that on the X150 the rear pads always wear more quickly than the front pads - "perfectly normal for this car" - but he did not elaborate as to the cause.

 

OK so you guys made me go out and look at my pads. So the fronts look about 50% and the rears look like about 30% left. So I am seeing more wear on the rears. They are OEM original pads and no have 20K miles on them. So I suspect I'll need to do a pad slap next year about the time I usually get the oil change ( April). Rotors look great with a minimal if any ridge so they'll be left alone. By the way I don't use the E-brake so I can't assume it is causing any of the problem. 2012 XKR convert wit 20" rims.

 

One note for comparison:
My 2010 XKR always has had 2x the brake dust on the front than the rear.

I dont know what it means if anything- just sharing a reference.

 

I would assume it's because the front pads are maybe twice the area of the rear pads.

 

Here is an excellent video that shows what we were discussing- the rear brakes being used for traction control. I.e. when you make spirited turns.

https://www.youtube.com/watch?v=K3m2...ature=youtu.be