On this CDI I just got, one of the things I'm happiest about is the fact that it was driven largely highway miles. One evidence of this is that the rear rotors and pads are original at 148k miles. Even considering the highway miles, that's still pretty impressive. It will be interesting to see how long they go.

But what I just noticed is that the FRONT brakes were only done once and at 123k miles. Never really seen anything like this....maybe I just don't have much familiarity with cars driven only highway miles. But I also wonder if MB's claim that the SBC reduces brake wear also has something to do with it. If so, I'm glad I have SBC...until it fails, of course.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

If a SBC car is being properly driven, I doubt that SBC will change brake wear rates. There just isn't any way to get around kinetic energy that needs to be converted into heat.

If someone drags the brakes while driving, SBC might have an effect but that would have to be verified.

Brake ( and clutch ) wear rates are ,for all practical purposes, zero when driving steady state so you would have to figure % of city driving to get a good sense of wear rates. ( RE: deduct all but a few % of the highway miles from total miles leaving you with a more realistic picture. ).

My 97 SL320 at 124 K had what appeared to be original rotors all around and likely rear pads. It was originally sold in Florida and later made it's way to Charlotte NC, near as I can tell these are level ground states.

My 96' W210 had front pads and rotors at 164k then front and rear pads and rotors at 312k.

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

I drive thru the mountains in my Dodge/Cummins to the track in Ohio and I can assure you that mountain driving is WAY harder on brakes than driving on our coastal plain. Mine are glazed right now following the last meet and I need to get after that.

SL 320 hit it on the head - you have to convert the rolling (kinetic) energy to heat and it's going to take X amount of force to do that. The pads, of course, are the means to apply that force and they'll wear as they need to to do that job. If yours are holding up well it's more likely a function of the pad material and the rotor formulation - and wise use of the brake pedal.

Dan

As in for the first time? Wow.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I still wonder if the system is smart enough to do things like look at the intended rate of deceleration and use the transmission downshifting to help decelerate. While at the same time reducing pressure on the brakes, thus reducing wear that way.

Just a hunch.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

BAS looks at brake pedal apply rate and takes over of the driver stabs the brakes then lets off but this won't help wear.



While possible with SBC, I'd be OK with the trans down shifting in a maximum effort stop but not for regular use. Downshifting to slow a car is hard on the drive line / trans. ( As opposed to holding a gear to control speed. )

Remember that a Diesel has no throttle (one of the reasons for the superior mileage) so there is basically no engine braking.

Dan

?????

I think you meant to clarify that there is negligent intake manifold vacuum due to no throttle.

But Mileage is better than gasoline due to the higher flash temps which allow higher compression ratios, which allow better extraction of the chemical energy once injected.

And there is plenty of compression braking in a diesel, due to each cylinder still compressing on the compression stroke, but not much subsequent explosion on the power stroke.

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Mark in MA
05 MB E320CDI 402k Granite Grey Metallic
05 MB E320CDI 267k Black
05 MB E320CDI 232k White
05 MB E320CDI 209k Tectite Grey
99 Dodge 2500 Cummins 5sp 148k
62 Jeep CJ-6 120k

My 06 CDI has gone through several brake parts replacements.
I don't have it's books/records/Carfax with me, so I could chronicle them here. But it's been considerable in R&Rs for such low mileage.

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'06 E320 CDI
'17 Corvette Stingray Vert

My wife has a driving style that seems to prolong brake and tire service requirements usually. Although some of the originally supplied tires will not go a great distance no matter how you use the cars.

When coasting, the cylinder compresses the air charge but since no fuel is injected no power stroke occurs. HOWEVER, the compressed air in a diesel is under enormous pressure, and so it acts as a spring pushing the piston back down even in the absence of fuel. So, the drag created by compressing the air is negated by the springy air pushing the piston back down where it cane from. This is the reason why diesels have less engine braking than gas engines (in addition to the throttle plate) and why there is a need for a Jake Brake on large trucks. The Jake Brake pops open the exhaust valve when the piston is at TDC compression to release the compressed air, and then closes it so the piston falls to BDC pulling a vacuum. The piston works against the air going up, and then works against the vacuum going down. That makes for VERY strong engine braking.

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'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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While an intake throtless diesel does not offer compression braking, in a maximum effort stop, down shifting could help initial deceleration and engine friction still exists. If the system was really smart it would neutralize the transmission so the now stored rotational energy in the engine does not continue to drive the car when it is near stopped. Remember we are talking about a maximum effort stop not a regular slow down / stop.

While it does not apply to the car in question, a diesel with electronic fuel injectors could offer engine braking by firing the injectors very early. I drove a 05 ish Ford F550 for a bit and found in tow mode going down a hill you can hear the engine firing but not in regular mode. It felt like there was some extra engine braking but I can't confirm that this was actually happening as some Fords had a exhaust flap to restrict exhaust for fast warm up that could also be used as an exhaust brake.