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Catastrophic brake failure - hard line ruptured (2001 ML430) – URGENT – check yours

2001 ml 430 - HARD BRAKE LINES RUPTURED DUE TO SEVERE CORROSION – check yours for your own safety!

While driving, my wife had lost braking on our 2001 ML 430. The brake pedal became very soft, and she barely stopped in the middle of a busy intersection. Luckily, no physical contact with other cars happened.

She proceeded shaken and scared, crawling toward our house as she was closer to our house than to any dealership or other helping hand. Experiencing numerous tense moments while driving, due to the lack of braking power, she finally parked in front of the garage leaving a trail of dripping fluid on the driveway. By the drip marks, one could easily see how she maneuvered herself.

Just several months ago, I replaced brake pads, rotors, and flushed the brake lines with MB fluid dot 4+. So far, the truck brakes' performance was excellent, until this happened.

To check the brakes, I started the car - lights on, brake pedal soft. Decided not to drive at all.

Upon checking the usual suspect places, I found that all calipers and rubber lines were in excellent shape, dry, and not exhibiting any abnormalities. Yet, brake fluid was dripping from the middle of the truck's left side, under the left doors.

Taking off the protective plastic which covers the underside of the vehicle where the brake lines run revealed a nasty picture. I found that a HARD BRAKE LINE was SEVERELY CORRODED and RUPTURED.

I've had many cars so far, and this is the first ever with a catastrophic failure of a hard brake line. Needless to say, I am extremely disappointed with the quality of this MB.

Called a dealership. They told me they had to bend lines to fit them. According to them, it will cost approximately $1,500., plus towing, and they are “not sure how much more work needs to be done.”

The truck is obviously out of warranty. I am thinking of writing a letter to MBUSA and requesting at least a reimbursement for the repair of the hard lines. Do you think such a letter will make any difference? What should I write and request? Do you think I should copy/write somebody else too?

On a side note, as I am not severely mechanically impaired, I looked at what it would take to bend new hard lines, and eventually replace those myself. In my view, I can do this as soon as the temperature permits (currently 10F ). Already located vendors for lines and tools.

Anyone knows what type of flaring ML uses – double/SAE 45 degree, or DIN/ISO bubble flare?

Learn from my experience!

FOR YOUR OWN SAFETY, CHECK YOUR HARD LINES!!!!

Don't be like me! Until now, I assumed that the weak links in the brake system were the rubber lines. I was wrong.
 

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There was and still is a recall/campaign on brake line chaffing. See if your vehicle fits the bill and contact M/BUSA and inform them that you were denied by a dealership, but also inform them that there is no expiration date on the recall/campaign.
 

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W163 Crash Test Driver
2008 ML350 (Me!), 2010 GLK350 (Wife), 2003 ML-350 (Deceased)
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I had a hard brake line (right rear) rupture in my last vehicle, a 97 Chevy Cavalier. It too had corroded away. Scary feeling when you hit the pedal and half your brakes are gone! Cost me less than $200 at an indy...don't know if he had to do any custom bending or not.

Glad she is OK!
 

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There was and still is a recall/campaign on brake line chaffing. See if your vehicle fits the bill and contact M/BUSA and inform them that you were denied by a dealership, but also inform them that there is no expiration date on the recall/campaign.

Thank you, 43sqd. I looked at the pdf file, and it seems that they are concerned about chafing in the engine compartment area between two lines (fuel and brake), and not corrosion of the brake lines. I'll try talking with the dealership although they insist I bring to them (tow at my expense) the truck so that they can look at it.
 

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2000 Mercedes ML55 AMG, 2006 Mercedes ML350
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i had 2 lines replaced a few months ago by Mercedes. mine didn't break before but they were rubbing.
 

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2001 ML430 Sport bought in very nice shape despite 156K miles in August 2010
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US2001..Rather than sourcing materials, bending tools and bubble flare tools, it is less work [and risk] to buy a replacement brake line. They are available. Doing the replacement is straightforward, but you will need to do a complete fluid flush when you are done. Google Motive Power Bleeder, which is perfect for this job.

I suspect there may have been some previous damage to the line. All it takes is to have the paint system scraped off, and road salt will do the rest. Its remakable how well the lines stand up over time, provided the paint system is not damaged.
 

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Discussion Starter #7
US2001..Rather than sourcing materials, bending tools and bubble flare tools, it is less work [and risk] to buy a replacement brake line. They are available. Doing the replacement is straightforward, but you will need to do a complete fluid flush when you are done. Google Motive Power Bleeder, which is perfect for this job.

I suspect there may have been some previous damage to the line. All it takes is to have the paint system scraped off, and road salt will do the rest. Its remakable how well the lines stand up over time, provided the paint system is not damaged.
Thank you, APKhaos for your suggestions and for the diagram. I agree with you that there is certain risk when working on your brakes, although I feel that for me personally, I wouldn't be taking a huge risk if I do the brake lines flaring myself.

So far, I have no success finding replacement, pre-bent brake lines. Even the dealership told me that they have to bend lines themselves. I found some places that would cut straight lines and flare them to my specified length (which I don't have, as I have not measured the total length of my lines) . Also, there are places that sell straight lines with certain lengths, which means I have to bend and fit-connect several ones to complete the whole line.

Fedhill co sells this Cunifer(TM) line, which they claim does not rust. It is more expensive but they also claim that it is easily bendable. They also loan their flaring tool. Anyone having experience with Cunifer(TM)? Are you sure that the flaring is "bubble" type?

As to flushing the lines, I agree, I have to do this. I have a Motive Power Bleeder, which I used on this car several months ago when I changed my rotors, parking brake shoes, and flushed the system. For those who had never done this, I can attest that using the Motive Power Bleeder makes the whole process a lot easier. Now, since the brake fluid level has fallen below the bottom of the brake fluid tank, I have to bleed the whole system, which will do also do the flushing. The thing I am not familiar with is how to deal with bleeding the BAS and other systems, if any.

Since I am the only owner of the vehicle, and I have never before opened the place where the lines are run, I can tell you that there hasn't been any damage to the lines unless they had come damaged from the factory. That is why I am suggesting to other people to check their lines as they are part of a vital system, the failure of which can be extremely dangerous and life-threatening.
 

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Brake fluid is hydroscopic.

Over time, the fluid absorbs water and lines can rust from the inside as well; they need to be changed and flushed periodically.
 

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Thank you, APKhaos for your suggestions and for the diagram. I agree with you that there is certain risk when working on your brakes, although I feel that for me personally, I wouldn't be taking a huge risk if I do the brake lines flaring myself.

So far, I have no success finding replacement, pre-bent brake lines.
PHP:
 Even the dealership told me that they have to bend lines themselves.
I found some places that would cut straight lines and flare them to my specified length (which I don't have, as I have not measured the total length of my lines) . Also, there are places that sell straight lines with certain lengths, which means I have to bend and fit-connect several ones to complete the whole line.

Fedhill co sells this Cunifer(TM) line, which they claim does not rust. It is more expensive but they also claim that it is easily bendable. They also loan their flaring tool. Anyone having experience with Cunifer(TM)? Are you sure that the flaring is "bubble" type?

As to flushing the lines, I agree, I have to do this. I have a Motive Power Bleeder, which I used on this car several months ago when I changed my rotors, parking brake shoes, and flushed the system. For those who had never done this, I can attest that using the Motive Power Bleeder makes the whole process a lot easier. Now, since the brake fluid level has fallen below the bottom of the brake fluid tank, I have to bleed the whole system, which will do also do the flushing. The thing I am not familiar with is how to deal with bleeding the BAS and other systems, if any.

Since I am the only owner of the vehicle, and I have never before opened the place where the lines are run, I can tell you that there hasn't been any damage to the lines unless they had come damaged from the factory. That is why I am suggesting to other people to check their lines as they are part of a vital system, the failure of which can be extremely dangerous and life-threatening.
The parts manager you spoke to is completely uninformed or is flat out lying to you. Each brake line has its own part number, therefore if ordered with that number you would receive it preformed.
 

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W163 Crash Test Driver
2008 ML350 (Me!), 2010 GLK350 (Wife), 2003 ML-350 (Deceased)
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The parts manager you spoke to is completely uninformed or is flat out lying to you. Each brake line has its own part number, therefore if ordered with that number you would receive it preformed.
That makes sense. I cant imagine any modern vehicle having replacement parts that would have to be custom formed.
 

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2001 ML430 Sport bought in very nice shape despite 156K miles in August 2010
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^ +1

Listen to 34sqd - he is among the most reliable sources on this board.
Order the MB part and you are in business.
 

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This happened to me few years back in old 93 Dodge Intrepid, in front of me was brand new VW Jetta and we were going about 50 mph. Trafic stoped dead, about 30 cars front of me, I had brakes for split of a second, then nothing. I believe my guardian angel was not sleeping at that early hour. I pointed the car between ditch and cars, passing them on the graveled sholder and even with emergency brake applied, I past flying next to 10-15 cars before comming to complete stop. Now its funny but it was not at that time. People thought I must be crazy driving on the sholder in that speed, but I had no choise.
Pushed it across the street to church parking lot and called my manager to pick me up since it was 3 miles from work. At lunch, my body went with me to check it out, steel brake line for rear left wheel bursted out from corrosion.
Crimped it shut with pliers, add it fluid and drove off.
Measured the lenght, got two lines from Napa with coupling for $25 and replaced it. Fitting were already installed on those lines, I just had to bend them with $8 tool from Harbor freight. Replaced the other rear line week after just to be safe.
Compression couplings between these premade lines are as good as the connection between flex rubber hose from caliper and steel brake line.
 

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2001 ML430 Sport bought in very nice shape despite 156K miles in August 2010
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US2001ml430,
You will get pre-formed lines from MB - 43sqd confirmed that.
Given there was no accident damage to the failed line, you might want to think about replacing both rear lines. They both run the same path, so its reasonable to think that if one failed due to corrosion the other can't be in much better shape. Sorry this has happened to you, but once you have the lines in hand its a pretty easy fix.
 

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Discussion Starter #15
Thank you so much for your input. I'll call other dealers to order the lines. I'll keep you posted.

Still, for your own and your loved ones' safety, you might want to check yours. Obviously the lines are out of sight but not out of trouble, and this can be BIG TROUBLE.

Stay Safe!!!!
 

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43sqd, not clear to me from reading the recall, does this apply to 8 cylinder trucks only?
 

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Brake fluid is hydroscopic. Over time, the fluid absorbs water and lines can rust from the inside as well; they need to be changed and flushed periodically.
Oooohhh...never thought of that. That is probably why my line burst on my last vehicle, as I had never changed the fluid. :eek:

Note to self: Buy power bleeder and change fluid this spring!
 

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Most major brake or hot rod shops could bend custom stainless lines and install them for less than the dealer. If the OEM preformed lines are too difficult to install you could also use braided and coated flexible lines.

I must admit that I've never taken a look at my lines. Probably a good idea to add it to the list.
 

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Hi All,

Raising an old post.
Lot of good info given above. Thanks to you previous posters I was able to turn a potentially expensive repair into an inexpensive fix.

Last week I experienced the 'three lights of doom' illuminating on the dash whenever pushed on the brake pedal while under way :eek:- issue was low brake fluid (despite recent top up). Trouble traced to pin hole leak in one of the two metal brake lines for the rear wheels - hole was roughly half way between front and rear wheels under the plastic cover accessed from under the car. The hole was exactly at one of the clips holding the brake line to the frame (likely pipe kept wet all winter long by wicking of water / adhesion between pipe and clip). :crybaby2:

The two brakes lines cited above cost about 300$ (tax included) from the local dealer (after a minor freak-out at the prospect of 700$? - 1000$? repair), equipped with previously purchased 'SAE/double flare tool' and a 'hand held tubing bender' I opted to make and install my own repair sections.

the cost? oh about 30$ - i.e 10% of the dealer parts cost. (i.e well less than just the tax on the dealer parts' :wtf: (15$ for 25' of 3/16" brake line. 8 male end fitting at 40 cents each. 4 Female-Female unions at 1.50$ each). Plus a jug of brake fluid too of course.

I am an avid rustproofer having had brake lines rust out on my two previous cars ( 1988 Saab, 1996 Mercury 'Wagon) - this is what you get if you keep your cars too long.....

the point is i had been avidly rustproofing but "thanks" to the cover running along the bottom driver side rocker panel the rust proof solution was prevented from coating the brake lines which had significant rust.

not a pleasant job but if you live in an area where they use road salt as a minimum you might want to take the hit and pull off the plastic covers and examine and rust proof your brake lines.

as stated I opted to replace the rusted section in the manner I did because a) of the tools and materials either at hand or locally sourced b) the extremities of my brakes lines were not rusty due to thick layer of rust proofing. A better approach for someone starting from a different place likely would be use of Bubble/Iso flaring tool and fedhill flexible alloy brake lines.
 

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US2001..Rather than sourcing materials, bending tools and bubble flare tools, it is less work [and risk] to buy a replacement brake line. They are available. Doing the replacement is straightforward, but you will need to do a complete fluid flush when you are done. Google Motive Power Bleeder, which is perfect for this job.

I suspect there may have been some previous damage to the line. All it takes is to have the paint system scraped off, and road salt will do the rest. Its remakable how well the lines stand up over time, provided the paint system is not damaged.
Hi my 2000 ML 320 brake line also ruptured. I ordered replacement brake lines from mboemparts.com and hope to replace them by myself. When you said it is straightforward, can you give some tips how best to do this? Thanks.
 
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