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Brakeline Corrosion near fittings on 2009 C Class 4MATIC
MD Brake Experts,
I was at the dealer yesterday for a B (Major) service, and the dealer brought to my attention that there is corrosion (to varying degrees), near the fittings of all of my brake lines. Fronts worse than rears. centre lines (where covered by the access panels) even worse. They put the car on the hoist and I took a quick look. it appears that the 'coating' on the metal line wore off, and that corrosion has started to set in an inch or there abouts near the fittings. Dealer recommends that all of the lines be replaced at a cost of $3,700 Cdn (before Taxes), or at least to replace the centre brake lines. They could work a better price, but apparently 18 hours of labour 'because the rear axle has to be dropped'. The centre brake line was flaky when I took a look at it, but just on the elbows. I've read that surface rust could be cleaned off and oiled, and possibly that sections near the joints could be 'repaired'. My car is otherwise in pristine condition in and out with 99K mileage. I expect to keep it for quite a few years more. Needless to say, I was not expecting this for a 10 year old vehicle, but nor do I want to scrimp when safety is concerned. Car is parked in outdoors during the weekdays (for work), but otherwise garaged. We have harsh winters here in Alberta, and our city (Edmonton) recently started spraying roads with a high content salt solution to prevent icing in the winters.
I had booked the repair originally, but now have postponed because I would like to consult with other MB owners. Have any of you encountered similar problems with your 'newer' Mercedes? I have included some 'poor quality' pictures that the dealer took, which in essence show that the protective coating have come off in a few areas. Have not yet had a chance to take wire brush to the pipe to see how deep this rust has penetrated.
You comments and/or advice is sincerely appreciated!
I had to replace my whole left rear brake line going from front all the way to caliper earlier this year. I don't see where they would need to drop the rear axle at all and that price seems way too high in my opinion even for dealer.
My worst area was under driver side rail where the plastic cover is as well as under the rear trunk area. I had an actual leak it had gotten so bad and that's how I discovered it. When I asked a couple months ago on the forum here no one had ever seen or experienced it before so it must be a rare thing but if you have the ability you can do it yourself for much cheaper.
I think it was about $50 for the steel line that ran from front ABS Module all the way to rear passenger brake caliper. There are no connection points for any brake line at any midpoint so all lines will be ran as one piece and of course you have to do all the bending yourself.
It's easy enough I don't know if I could swallow an almost $4k bill for that repair but at same time it will be a time consuming one although as I said I see no reason rear axle would need to be dropped, plenty of room to run and replace that rear passenger brake line without removal.
I appreciate you taking the time to write me. So did you replace all of your lines of just the rear left line? Are you saying that there are no couplings anywhere from the front junction box to the rear brake hose fitting? And do all of the rear lines run through the drivers side rocker access panel? When I got the quote from the dealer, it sounded like they could just replace the 'center' piece of hard line (under driver's) side door separately, so I just assumed there was a coupling in there somewhere. I am going to pull the wheels, and check the lines near the fittings up close. If it appears to be surface rust only, I might consider brushing, sanding, and using an industrial clear corrosion inhibitor sealant, and monitoring spring and fall for discoloration when I do my tire changes. If the rears are connected as one piece to the 'centre' line (under the doors), I might have no other choice than to replace the whole lines. Do any lines run under the right door, or do they all run under the left? How hard was it to flare the lines? Thank you for your help!
I took off the driver's side front and rear tires and used a small wire brush to expose the lines near the brakehose fittings to take better pictures than the dealer had taken. Photos 1 and 2 (rear line). Photo 3 (under side rail). Photos 4 and 5 front line. Should I POR40 the exposed metal on the good lines and replace the bad only? Replace all? This must be a rare issue, as I was hoping for more people to chime in with their own experiences.
Here in crappy/salty Ontario, my car has gone through 6 winters, and I don't have this issue.
I'll take photos later but I did confirm.
In OP's case, why not just use some rust-stop type paint? I don't know why this may or may not be good/bad, but just a thought. It doesn't look like it's eaten through the cable?
Agree to buy a bunch of cans of brake cleaner and prep everything. Then spray with por or something.
Going to get a tiny leak first if it went through. Then just replace that piece. Do not have this done at dealer. Nothing complicated here but will need computer to pump abs unit while bleeding.
Might really be be helpful to have dealer show you the replacement pieces. Good to get a visual on each piece to understand exactly what they are doing.
I appreciate you taking the time to write me. So did you replace all of your lines of just the rear left line? Are you saying that there are no couplings anywhere from the front junction box to the rear brake hose fitting? And do all of the rear lines run through the drivers side rocker access panel? When I got the quote from the dealer, it sounded like they could just replace the 'center' piece of hard line (under driver's) side door separately, so I just assumed there was a coupling in there somewhere. I am going to pull the wheels, and check the lines near the fittings up close. If it appears to be surface rust only, I might consider brushing, sanding, and using an industrial clear corrosion inhibitor sealant, and monitoring spring and fall for discoloration when I do my tire changes. If the rears are connected as one piece to the 'centre' line (under the doors), I might have no other choice than to replace the whole lines. Do any lines run under the right door, or do they all run under the left? How hard was it to flare the lines? Thank you for your help!
I can chime in and help answer most of what you asked.
First, yes each line is a solid line going to each caliper hub area from the ABS module. All the rear lines run along the driver side rocker on a left hand drive car. If you purchase the brake lines from MB know they just come as a straight piece, no pre-bending at all. You can flare the current line easily as long as you take your time and give yourself room. I at first I did just a section until I saw more corrosion and that made me want all new line.
I did do just the passenger rear brake line, it is the one that has to go under the trunk area and over the rear diff. They are all individual lines running to each caliper so no "center" line under the cover from underneath on drivers side.
Honestly, once you remove the undersides rock shield and the front and rear wheel arch lining it's a rather simple job of doing the actual lines. From your pictures i'd say you have a good chance of being able to just repair the rust and ovoid cutting and splicing of the lines.
If you do have to bleed the brake lines you can easily do the tried and true method of one pumping the pedal and the other turning the bleed screw with the car running in order to bleed ABS module. Hope that gave a couple quick answers to some of your questions.
Catmandoob, I have a question for you regarding OEM brake lines for the C Class that one would purchase from the MB dealership.
It is my understanding that the lines are NOT pre-formed but come in a straight line of pipe based on your last thread. I have a dumb but rather important question to ask. Did the lines come pre-flanged with fittings connected in the correct lengths of pipe based on the location of use, OR did you have to do all of the flanges yourself? There was no mention of this in your response. My understanding is that the flanging process would not be that easy, so I thought that I would clarify. Would make a big difference to me in whether I would consider tackling or not. Thanks!
Catmandoob, I have a question for you regarding OEM brake lines for the C Class that one would purchase from the MB dealership.
It is my understanding that the lines are NOT pre-formed but come in a straight line of pipe based on your last thread. I have a dumb but rather important question to ask. Did the lines come pre-flanged with fittings connected in the correct lengths of pipe based on the location of use, OR did you have to do all of the flanges yourself? There was no mention of this in your response. My understanding is that the flanging process would not be that easy, so I thought that I would clarify. Would make a big difference to me in whether I would consider tackling or not. Thanks!
Ah yes, good questions and the answer is yes they come pre flanged and ready to put in place. My length of line did cover the entire span, you have to watch your bends and make use of it in a best case scenario.
It did take me 2 tries of routing for it to reach ABS to bracket that bolts to flexible brake line. Would be simple enough to use a compression fitting if you are short and just add a piece so you can have correct flanges and fittings on both ends. I never did find out what thread MB uses and never could match it with my local auto parts store so it was a life saver that MB's brake line came ready to put in place.
Last edited by catmandoob; 08-06-2018 at 04:11 PM.
Just a FYI. I have been bleeding brakes for 40 years and I accidentally drained the abs on a 07 cls550. Tried for weeks with a pressure bleeder to get the air out and no chance. Took it to a shop with Star and he cycled it while bleeding and air came bubbling out. Been perfect for years.
Just in case you tackle it.
Warning indeed. Just developed this problem on my 2009 W204, 120K miles, otherwise mechanically perfect/well maintained. Dealer wants $6K to fix (car isn't worth $6K) because as above, they say the rear subframe has to be dropped. MB must be using sub quality brake lines on this car - I've had VWs and Fords and Hondas run out to 170K+ miles, never heard of a problem of a brake line corroding/rusting through. Other high mileage W204 owners take note. See the video below, the subframe does not have to be dropped to fix this problem - finding a shop who can do this is a different story.
Figured I'd "update" my post, 2 years later from my comment...
Rusted brake line above rear diff, causing leak. 95k miles 2010 sits outside 365 days a year and daily driven, rain or snow.
So it's possible.
Possible indeed, not sure how MB messed this up but keeping an eye on my 2010 as well now, so far so good but looks to be starting. IMO easy fix though at least. Worth keeping an eye out everyone, and if it's mainly in the middle keep in mind you won't always see brake fluid on ground.
This is a very common problem on these cars. I bought my 2008 C300 with leaking brake lines. I had never done brake lines before (though I have done a lot of other stuff so I'm at least mechanically inclined). I replaced both rear lines in less than 6 hours with no experience. There is zero chance it takes a dealer 18 hours. And you do NOT have to drop any axles.
The all seem to be rusted like this one. No leaks yet.
Personally, I'd replace it before it inevitably fails. In a little research I found that many of these do fail. Brakes are a pretty important component you don't want failing at the wrong time. Use nickel copper line and you won't have to worry about rust again.
Personally, I'd replace it before it inevitably fails. In a little research I found that many of these do fail. Brakes are a pretty important component you don't want failing at the wrong time. Use nickel copper line and you won't have to worry about rust again.
I haven't even asked the stealership for a quote since I know it will be ridiculous. My good indy shop wants 2k for replacing all 4 lines. Another shop in town wants about $900, but Im not so sure about how experienced they will be with this sort of service. Question for you experts: how complex/difficult is this service? Should I trust my local shop?
I replaced 1 set of hard line in the rear with copper-nickel (appears to be the superior product). Was not difficult and did not have to remove anything except the body plate. The soft lines if anything should be even easier.
I just had the rear passenger brake line on my 2008 C300 burst on my way home from work last week in rush hour traffic on a 60 mile commute. I will be replacing it the old fashion way, DIY so I'll take pictures of the process. It was a sizeable hole at the bend above the driver side rear wheel where it goes across the vehicle, If this happens to anyone else and you are trying to baby it home, stop at the first auto parts store you can, buy a big bottle of brake fluid and don't let your reservoir go dry!
08-04-2018, 11:35 AM
Updated Photos
