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Hi folks, got my 2014 CLA250 4matic back from the shop for its B9 service, and they advise replacing the REAR brake pads and rotors. And rotors. Did I mention it's the rear brakes? Fronts are fine. 5% left on the rear.

Ok, in all my years with cars, rear brakes never go out first (65k miles on the clock). Note that I do trust the mechanic, but I'm wondering if anyone else has encountered this. A few questions to the forum brain trust:
  • Has anyone else had the rear brakes require replacement before the front brakes? Any ideas on the cause?
  • My mechanic advises replacing the rotors along with the pads because in his experience new pads alone end up being noisy. Does anyone have experience replacing the rear pads without changing the rotors? Any noise issues?
  • Does anyone have rotor recommendations? Pad recommendations?
Thanks in advance!
 

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If the inner pad is much thinner than the outer pad then the caliper system is stuck somewhere
The wrong pin lube will cause this over time (gets gummy instead of staying lubey)
A sticky caliper will increase wear rates and probably cause poor rotor wear ... so dumping the rotors is wise
 

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Hi folks, got my 2014 CLA250 4matic back from the shop for its B9 service, and they advise replacing the REAR brake pads and rotors. And rotors. Did I mention it's the rear brakes? Fronts are fine. 5% left on the rear.

Ok, in all my years with cars, rear brakes never go out first (65k miles on the clock). Note that I do trust the mechanic, but I'm wondering if anyone else has encountered this. A few questions to the forum brain trust:
  • Has anyone else had the rear brakes require replacement before the front brakes? Any ideas on the cause?
  • My mechanic advises replacing the rotors along with the pads because in his experience new pads alone end up being noisy. Does anyone have experience replacing the rear pads without changing the rotors? Any noise issues?
  • Does anyone have rotor recommendations? Pad recommendations?
Thanks in advance!

Be sure to do your own inspection of your brakes! My stealership told me at 60k that my brakes needed replacing because they were to 5-10% pad left. I just re-inspected them at 95k and they still have 30-40% on the front and 20-30% rears.
The reason your rears wear faster on these cars is because of traction control on the rear uses brakes as well as power transfer to maintain traction.


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Geee ... if so much rear pad material is used up in momentum vectoring then something is awry ... either that or lots of creative driving
That said, in another car, turning off distance tracking and lane centering significantly decreased pad wear at all 4 corners and saved a lot of gasoline ... on that car, friction based dynamics management aint such a well thought out solution.
 

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Geee ... if so much rear pad material is used up in momentum vectoring then something is awry ... either that or lots of creative driving
That said, in another car, turning off distance tracking and lane centering significantly decreased pad wear at all 4 corners and saved a lot of gasoline ... on that car, friction based dynamics management aint such a well thought out solution.
My 2014 does not have lane centering or distance tracking.


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Hi folks, got my 2014 CLA250 4matic back from the shop for its B9 service, and they advise replacing the REAR brake pads and rotors. And rotors. Did I mention it's the rear brakes? Fronts are fine. 5% left on the rear.

Ok, in all my years with cars, rear brakes never go out first (65k miles on the clock). Note that I do trust the mechanic, but I'm wondering if anyone else has encountered this. A few questions to the forum brain trust:
  • Has anyone else had the rear brakes require replacement before the front brakes? Any ideas on the cause?
  • My mechanic advises replacing the rotors along with the pads because in his experience new pads alone end up being noisy. Does anyone have experience replacing the rear pads without changing the rotors? Any noise issues?
  • Does anyone have rotor recommendations? Pad recommendations?
Thanks in advance!
I had this puzzling behavior on my Jetta sportswagen. Someone explained to me that the "bias" between the front and rear brakes is set towards the rear on some German cars.
It does not seem to be the case on my current 2014 Cla.. In my case the rotors tend to go before the pads. ( I get pedal pulsation when I brake at highway speeds.
When this becomes too annoying I tend to swap the rotors and the pads. Despite of what the dealer says, the rotors can be machined ( resurfaced)
I do the brake work myself, it costs me under $400 total in parts. front and rear. I have used Brembo and Bosch brand rotors, and typically Autozone DGC pads ( Ceramiic ) and Autozone
semimetallic in the rear. They have a lifetime warranty, so the pads do not cost me anything now.

This thing about replacing the rotors because they are noisy sounds like BS to me. Worn rotors have some concentric wear ridges on them, which causes the braking efficiency to be slightly less until the pads wear to match the existing rotor surface. This happens fairly quick, esp. if the ridges are not too pronounced. If you do not have rotor warping (ie pulsating pedal) and your rotors look good, you can get away with just changing out the pads.

You can certainly have the existing rotors re-surfaced, MB just likes to replace them every chance they get. esp if you are paying out of pocket.
The rotors have wear marks on the edge, asl long as they are not thinner than those marks it is safe to resurface them.
( "turning" the rotors should set you back maybe $20-30 per pair.

I had Brembos and Bosch Quietcast on front and rear, I tend to get pedal pulsation after 20-30K miles. Some people swear by the OEM Zimmermann-s, they are a bit pricey but nowhere near the extortion rates you have to pay to the dealer. The brake DIY is documented by myself and others if you search the forum,

All the best

Steve
 

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I have the Bosch Quietcast. Put them on Oct 27, 2018, they now are vibrating pretty severely when I brake now. I probably drove 25-30K miles on these. I consider 30K pretty good actually.
next thing I am going to do is try a different brand, and have these turned for the next time. I will ask the machine shop to check the runout and thickness variation.
If I can get the OEM Zimmermans for a good price, that's it, else probably Ac Delco or Wagner.
i probably go back to semi-metallic pads again. maybe it is the ceramic pads I have on now that are the problem..
 

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There's something fishy going on with Mercedes brakes. I had mine replaced at the dealeship 20K back. On my last service the brakes were replaced "no charge" because they only lasted 10k. I'm ready for my next service @ 70K and in only 10K they need replacement again. The dealership said they don't think they can comp them again since they did it on my last service. I don't care about another comp I just want the problem fixed! I have a friend that has done 3 brake jobs at the same dealer in 25K. I drive 90% highway miles. Something's wrong with this picture!

Anybody else in the same boat as we are?
 

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Wow ... I am sure a finite number of us have some issue or another
May not be the discs but the pads ... they dont seem to deposit an even layer of pad material which sooner later leads to that shakey feeling (like mine are finally starting to even though I hardly use them) and the disc edge runout is practically naught
Since Ive got nothing to lose am gonna scuff the oem Z discs with a disc brush to quasivirginize and see if the shakes goes away to prove the hypothesis ... and save a bomb
 

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my mechanic told me that Mercedes cla and c classes have a problem with the piston sticking causing premature wear. He said Mercedes is aware of the problem but has yet to address it. I'm not sure how much truth there is to his statement but his dad use to be the lead tech at the dealership so I do trust his word. I know I've had my brakes replaced at a fairly early life cycle in the car and questioned the longevity of the Mercedes pads.
 

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Hmmm ... related to sticky pistons might be the moisture sensing system? Cuz if thats wonky the pads will wear
Im guna pick his brain on Thursday as im going to drop off the car for the front rotors and brake replacement. Curious to see if only one pad is worn.
 

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@pa4ul
May I ask a favor ... since you are picking an expert's brain, perhaps I have something for the occasion.
If you could pass these observations along for an opinion, I would greatly appreciate it!! :)
My rotor surfaces used to be primarily silver, with the LF sometimes showing blue banding, no grooving.
However as of today, over the past ~1000 miles (now at 23566mi) the rotor surfaces have changed,
still no grooving, though lots of BLUE/GREY banding on all four. F pads ~11mm, R pads ~10mm.
I have some guesses, though sure could use an expert's eye:
LF
65194

RF
65195

LR
65196

RR
65197
 

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ill show him the pics and see what he says!
 

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Thank you mucho!
well I showed him the pictures and he asked first if your an aggressive driver? He then said either a brake line is getting clogged or the caliper is sticking. Either way the only way to find remedy is to replace everything and see wear after new parts are installed. But he was suggesting checking your brake lines first to see the color of the fluid.
 

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Has anyone looked at the rain/wet sensor feature? This is supposed to sense when it's raining and bring the pads in closer for quicker response in bad weather. Is this part of the sticking problem mentioned or is there something special the service dept. should be doing during brake jobs as these cars age?
 
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