Member Since: 25 Apr 2015
Location: Suffolk
Posts: 197
Absolutely Robbie, it's physics. However, yours and my, and many others, rear brakes have worn out quicker than the fronts. So something is going on and either the rear pads are not as good a quality as the fronts, doubtful, or the rear brakes are doing more work than we think they are and wearing out faster.
Why this is the case is something of a mystery, and my Disco and my FL2 are the only cars in 50 years of driving where this has happened. My Austin A30 didn't have EBD, ESP, traction control, ABS and all the other gizmos modern cars have and I believe that there are things going on when you drive this beast that you, as the driver, are not privy to. I totally agree that main dealer speak is often rubbish, but when I did my LR Experience day the instructor talked about all the things the car does to keep you going and maintain stability both on and off road, most of which are not visible to the driver.
The bottom line is don't always expect your rear brakes to outlast the fronts - it's called progress.FFRR Westminster TDV8
D4 HSE MY12 Aintree Green. Great car
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30th Jan 2016 10:31 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
My current best guess is that the increase in front pad contact area has effectively increased the life of these pads. Indeed, looking back it seems that my rears will last roughly as long as they did on my D3. If so I should probably be praising the increased life of the fronts rather than questioning the rears.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 01 Aug 2005
Location: Cornwall
Posts: 2572
Agree with that conclusion Robbie.
My prev D4 did 30k on first set of rears, just over 30k on second set, 60k on fronts.
The front pads are massive in comparison to D3 pads.Long succession of Disco's since 2001...
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30th Jan 2016 10:44 am
discoteca
Member Since: 08 Mar 2010
Location: Warwickshire
Posts: 1477
Also worth remembering for anyone reading this thread in the future, that there was a short run of D4s built broadly in 2010 (can't find the exact VIN range right now) which had different callipers and pads on the rear and the two are not interchangeable. I've got them on my mine annoyingly.
30th Jan 2016 2:02 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
They moved from aluminium rear calipers to the cast iron type from VIN AA547440 onwards, hence the change in pad shape.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50944
The application of braking power differs from the front to the back in that it actually favours more braking pressure to the rear in several applications ... for me this would seem to explain the difference.21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
30th Jan 2016 4:26 pm
LandPhil
Member Since: 25 Apr 2015
Location: Suffolk
Posts: 197
DG, that's what it says here.FFRR Westminster TDV8
D4 HSE MY12 Aintree Green. Great car
RRS HSE Lux MY11 Stornoway Grey
Freelander2 SD4 HSE-Best car I have ever owned.
30th Jan 2016 5:26 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
A lot of that article is utter hoop. Day to day you just do not drive in a manner that requires the ABS to keep the rears tame. Clearly max ABS braking is just that, as is intervention by the brake system when it all goes pear shaped. The brakes at the rear really do have less effect due to the apparent weight shift and moment arm of the vehicle. Setting aside the physics and adverse handling with more bias to the rear for a moment - if manufacturers really did extract more effort from the rears they would be much larger with much more cooling provision.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50944
For clarity I'm not going by the article ...I'm going by how the D4 braking system operation is described. 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
30th Jan 2016 6:08 pm
LandPhil
Member Since: 25 Apr 2015
Location: Suffolk
Posts: 197
Robbie wrote:
A lot of that article is utter hoop. Day to day you just do not drive in a manner that requires the ABS to keep the rears tame. Clearly max ABS braking is just that, as is intervention by the brake system when it all goes pear shaped. The brakes at the rear really do have less effect due to the apparent weight shift and moment arm of the vehicle. Setting aside the physics and adverse handling with more bias to the rear for a moment - if manufacturers really did extract more effort from the rears they would be much larger with much more cooling provision.
No, I disagree. The Disco4 braking system is not just press the peddle to stop. It does a lot more than that, and some time ago it was very well explained but I can't reproduce the technical detail. It certainly applies braking force to wheels when cornering, if it feels the need to maintain stability, and there is no way the driver would know that is happening, except the car corners well. No brake lights or ESP captions. Furthermore, brakes are certainly applied without the driver being aware when certain TR modes are in use.
Bigger, meatier brakes on the front of the D4 may well be part of the answer, but why did my, and others, FL2 suffer the same fate. LRs share many of the same systems to achieve the same results but with different software and I distinctly remember reading the LR blurb on the brouchure before buying my FL2 that braking was applied when cornering to maintain stability.
The apparent shift of mass forward when braking will obviously lead to more wear on the front pads. So something else is obviously happening well before ABS operation is noticed by the driver. If this wasn't the case you, I and others would not have replaced our rear pads before the front ones - as I have done on all cars before my FL2.FFRR Westminster TDV8
D4 HSE MY12 Aintree Green. Great car
RRS HSE Lux MY11 Stornoway Grey
Freelander2 SD4 HSE-Best car I have ever owned.
30th Jan 2016 6:29 pm
LandPhil
Member Since: 25 Apr 2015
Location: Suffolk
Posts: 197
Next question
Why, when I select the "QUOTE" button doesn't the quoted text appear in a nice boxFFRR Westminster TDV8
D4 HSE MY12 Aintree Green. Great car
RRS HSE Lux MY11 Stornoway Grey
Freelander2 SD4 HSE-Best car I have ever owned.
30th Jan 2016 6:30 pm
discoteca
Member Since: 08 Mar 2010
Location: Warwickshire
Posts: 1477
LandPhil wrote:
It certainly applies braking force to wheels when cornering, if it feels the need to maintain stability, and there is no way the driver would know that is happening, except the car corners well. No brake lights or ESP captions.
I'm sorry but that simply isn't true.
DSC as LR call it rather than ESP (as some other manufacturers call it) brakes individual wheels to maintain stability based on a number of inputs. It is the only system on the car capable of autonomously applying braking force. Every time that happens the DSC light will flash. If it doesn't flash it isn't doing anything.
Taken from the LR workshop manual:
DSC Warning Indicator
The DSC warning indicator is an amber coloured warning indicator located in the tachometer.
Each time the DSC or the ETC function is active, the DSC warning indicator flashes at 2 Hz. If DSC has been selected off, or there is a fault that disables the DSC or the ETC function, the DSC warning indicator is continuously illuminated. If DSC has been selected off, vehicles with the high line instrument cluster also display a message, advising that DSC is switched off.
For additional information, refer to: Information and Message Center (413-08 Information and Message Center, Description and Operation).
Operation of the DSC warning indicator is controlled by a high speed CAN bus message from the ABS module to the instrument cluster.
When the ignition switch is first turned to position II, the DSC warning indicator illuminates for approximately 3 seconds as a bulb check. If a fault during the previous ignition cycle caused the DSC warning indicator to be illuminated, the DSC warning indicator may remain illuminated after the next bulb check, even if the fault has been rectified and cleared from the ABS module; the DSC warning indicator may remain illuminated during vehicle operation while additional checks of the related inputs are performed.
31st Jan 2016 2:01 am
discoteca
Member Since: 08 Mar 2010
Location: Warwickshire
Posts: 1477
Furthermore EBD, electronic brake force distribution, on a D4 can only reduce braking effort to the rear wheels not increase it so that isn't related to the quicker wearing out of rear pads.
Again from the workshop manual:
EBD
EBD limits the brake pressure applied to the rear wheels. When the brakes are applied, the weight of the vehicle transfers forwards, which reduces the ability of the rear wheels to transfer braking effort to the road surface. This can cause the rear wheels to slip and make the vehicle unstable.
EBD uses the anti-lock braking hardware to automatically optimize the pressure of the rear brakes, below the point where anti-lock braking would be invoked. Only the rear axle is under EBD control.
31st Jan 2016 2:10 am
Dave T
Member Since: 03 Jul 2009
Location: Glasgow
Posts: 6902
My rears also wore the most, but that was exacerbated by them seizing in the calipers and wearing unevenly. That was after 3 years and about 37k miles, fronts still had a bit of life left but discs were well worn and I don't think they would last two sets of pads so replaced the lot.Joined the BMWX5 45e group
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31st Jan 2016 9:41 am
wiggs
Member Since: 03 Sep 2006
Location: Manchester
Posts: 14368
LandPhil wrote:
Next question
Why, when I select the "QUOTE" button doesn't the quoted text appear in a nice box
It won't let you if you are the next poster ( as the question / answer or whatever is right above you )
You can quote once there is someone else in betweenG4 Gone ...but not forgotten
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