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In my diagram it seems to be showing a connection in the rear two brake lines. If true that would be fantastic and I can just replace the rear section, but im not sure thats what is actually installed. I'll have to take a look.
When I look up the fittings it says they fit Mercedes 1954-2025 vehicles, so its hopefully easier to get the exact replacement parts. I found they have the brake line at my local MB dealer for $60 which i dont think is that bad since it has the fittings installed at each end. But the line is listed for many other cars so im sure its not the correct length and i'll have to cut and flare one of the ends anyways. I'd rather keep all the fittings the same size/thread that is in the car already.
I want to find out what the part # is for the fitting I marked in red in a diagram below. I think that is the fitting that goes to the flexible lines?
My apologies buddy in that I did not zoom in to see the above repair was done with flared unions, which can be acceptable. I still stand by replacing lines as a single unit...
Apologies accepted, no harm done. :-)
No argument here, it certainly would be nice and preferred to replace whole line. It also would be nice to have brand new car, but this is not realistic right now. My repairs is absolutely cheapest option but I'm sure it is safe and sound. We can discuss how comprehensive or long lasting what I did is, but the fact that I did it for less than 1/100 of what Mercedes trying to charge for it. And I guess with some patience, one can do whole line, from master cylinder to the flex hose, with the same kit/cost. This was just beyond my objective at this time.
Reality check: My R350 has 140KMiles. When I got EV and tried to trade it - all dealers like one offered me only $2K. I know I cannot get half decent car for x3 as much. And my R350 still a very nice ride! Whole family, from grand parents to kids prefer road trips in R350 to any other vehicle. More: after owing EV for 2 years, the reality is that you cannot get rid of ICE, yet. Charging infrastructure is in very sad state. So we are keeping R350 as a spare and for occasional long road trips. For whole last year I think I put less than thousand miles on it.
With trade-in value of only 2K, adding any significant maintenance cost to it make no sense. And sudden death of it also a daily possibility. I've seeing perfectly healthy MLs (closely related) and Rs with over 250KMiles. But also seeing them dying suddenly with engine or transmission problems under 100KM. So with any luck it may stay in the family for a while. It also mean that I cannot allocate significant budget for it.
My first objective for my brakes splicing was ability to get on the road at minimum cost, so I do not have to occur cost of towing. So I chose to splice the lines by myself. I also did inspect remaining sections and I do not see anywhere else any loss of coating on the lines, the rest of the lines look fine to me, so far. Learning the problem - I certainly will be checking condition of the lines carefully and frequently.
Little peace of mind: when my lines leaked, even after I lost most of the fluid, I still have some braking. Obviously front contour is independent. Not something I would consider safe and reliable, but apparently it was enough for me to make home without accident. (this might be the reason Mercedes does not have to recall rusty lines).
Interesting observation: the day of the leak, before braking fluid float sensor dropped below minimum, loss of braking was already significant. Within hour I got red message that fluid is low. I am still able to start the engine and move car around. On next morning it refused to allow me to start the engine till fluid level back to normal. I really appreciate such level of refinement of onboard software.
I want to find out what the part # is for the fitting I marked in red in a diagram below. I think that is the fitting that goes to the flexible lines?
I guess this thread turning into repair exchange. Oh well, let's go with it till moderator create new thread for us elsewhere:
Tim, you are trying to replace sections 260 and 360, as whole, no additional splicing? Certainly doable.
I do not think you need parts 220, those are just clips and unless damaged - you should be able safely reuse old clips.
Unions 280 and 380 I am sure is the same part. Just check what kind of flare it takes. I recall that Mercedes unions are bubble flare. I read that folks usually cutoff original union and use US spec double flare.
Union on your image appeared solid nickel. Unions in my kit are brass but all nuts are mild steel with yellow zinc chromate coating (looking like brass) and then colored (bi-metal galvanic corrosion possibility anyone?). Nickel union probably safer for steel lines. If you value you r car - get nickel alloy lines.
Hoses (flex lines) at $60 OEM, no brainer, get original set. I've seeing many aftermarket hoses to fail. Nothing as good as original here.
Here my expertise ends. But there are ways to figure out path forward: with hose in hand - figure out thread they have or try fittings from the kit or read descriptions very carefully. The kit I got there are x3 pairs of extra fittings, in bright colors. Those I believe to mate with flex hoses. I cannot quickly find any reference about threads on Mercedes brake hoses. I also recall seeing some claim US and Euro specs Mercedes use different brakes threads. this might be bogus. You need to figure it out and find matching threads.
You probably will need access to the lift, if you would like to thread whole section without splices. No lift is another reason for what I did.
x3 meanings of "thread" in one section. Hehe. Not to get confused.
I was just curious what the part# is for the brake line fittings that are installed in the car, the hard lines to the flexible lines.
When I look up the hard brake lines by part# it seems they are listed as fitting 1954-2025 Mercedes. I know they are just a rolled up length of brake line with two fittings already installed. Have to unroll it, make all the necessary bends, cut to fit and install.
When I searched around for threads on replacing the brake lines I keep coming up with:
It goes back further than that, mines a 2008 and the brake lines failed maybe 2-3 years back but was only charged 300-400£ to have it fixed. At that time I had no subframe rust (atleast visible maybe it had started since it rusts from the inside out) but now I'm dealing with a rusted subframe and although Mercedes agreed to fix it, they're telling me the parts been on order for the past 4 weeks, and also that if any other part needs replacing, even bolts that I'd get charged for it.
mine has failed as well. I own a 2009 C300 and repair quote is 5K
It looks like you guys in the USA are being absolutely shafted at the prices mentioned - yes the MB rear brake lines rust, the left side under-tray needs to be removed and the lines checked for rust. It they are OK, rustproof them. The line to the right rear brake runs above the rear subframe and does rust.
There is no need to replace the whole brake line to the ABS pump. It is no more than 3 hours work maximum to replace the line that runs above the subframe and there is plenty of room to do a proper join behind the left hand wheel arch liner.
There is nothing wrong with joining a brake pipe provided the correct method and joiner is used. There is mention of double-flares on here - forget that, all the brake lines on modern Mercedes use single DIN flares. Double flares, called SAE flares, went out with the arc. You need the correct tools and fittings for a DIN pipe join, it's not difficult. Use Copper-nickel pipe, it's resistant to rust and easy to work with.
There are 73 complaints submitted since 2020 (that I found) describing this exact issue all isolated to certain models and all involving rear brake lines corroding away. These brake lines are all beginning to fail and Mercedes needs to acknowledge the fact and extend the warranty. I made a histogram to see when these things started failing. We can see that the failures will continue to happen as more vehicles get older and more brake lines corrode.
Have you or anyone else heard of an update or future in the works update to this? Has Mercedes admitted/recognized that the rear brake lines are also susceptible to the rusting and corrosion that the rear subframe endures?
It goes back further than that, mines a 2008 and the brake lines failed maybe 2-3 years back but was only charged 300-400£ to have it fixed. At that time I had no subframe rust (atleast visible maybe it had started since it rusts from the inside out) but now I'm dealing with a rusted subframe and although Mercedes agreed to fix it, they're telling me the parts been on order for the past 4 weeks, and also that if any other part needs replacing, even bolts that I'd get charged for it.
Noticed Brake fuild on my driveway after letting the car sit for a couple of weeks. I have a 2013 E550. Mercedes changed my rear subframe free for rust but I agree the brake lines should have been changed as well. I have it at an independent shop getting new brake lines. This is a serious issue Mercedes should address. Clearly they didn't treat the lines or subframe with rust prevention.
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in that I did not zoom in to see the above repair was done with flared unions, which can be acceptable. I still stand by replacing lines as a single unit...
