Another "in my 'shop today"

[Uncle Benz]

I didn't get a picture today sadly. A 2006 CLS, complete brake failure. Metal pipe on the offside to the rear caliper, rotted right through. Typically it was completely hidden by the plastic plank running down the floor of the car, so could never have been picked up on an MoT test. The pipes have some little rubber sleeves to prevent rubbing, but these seem to be the culprit, holding moisture between them and the pipe, and rotting away. The owner was shocked at the level of pedal effort required when the SBC system goes offline. Yes, it is quite a surprise Sir!
Anyway, new pipe made and fitted, system bled and pressure maintained via Star for five minutes to check for leaks. Monday I'm going to pull the under tray off the other side to see the condition of the pipe there. If it look suspect I'll replace that one too. I will get a pic or two Monday for you.

 

[vtaylor78]

Great Uncle Benz , I’m sure that will help out a lot of people.
Look forward to the pictures.

 

[Brizzle]

I had exactly the same problem back in May 2018 - bl00dy scary when the pedal hits the floor without the car slowing down!

Both pipes were so rotten I was surprised the brakes had been working at all

 

[Rappey69]

I drove a Daimler mk2 around for a while with the servo disconnected as it was causing the brakes to bind on..
Was an auto so nice big pedal for both feet to push like mad to try and stop the car..
The servo needed the centre push rod adjusting to within tolerance.. What a pain that was to do, but the old stuf is repairable !

 

[Uncle Benz]

Pictures as promised...

The car in question. Quite a nice old thing actually. The Brabus badging would have to go if it were me though. 150,000 miles, and in rude health apart from the brake pipes...

Offside pipe from SBC unit to rear caliper. The problems started in the last eighteen inches, but twelve of those were where the MoT tester would never see...

The next picture hopefully shows you where the leak actually was. I'm hoping you can see the heavy pitting, and reduction in the pipe's wall thickness. I read a lot about people cleaning pipes up for the MoT test, and I'll admit it gets my goat a bit sometimes. These components are safety critical, and if they look like they are getting thin you'd be well advised to have them replaced. Sure, sometimes a little surface rust can be cleaned up and greased to get through the test, but if you are doing the same bit year after year maybe you should think about how much pipe is left...

Rant over, as you were

 

[vtaylor78]

Good advice Uncle Benz, thanks for putting pictures up.
Look forward to the next episode

 

[Steve@Avantgarde]

We do so many brake pipes these days. Mainly because they are made from steel and once the salt gets under the rubber coating, it rots fairly quickly. We have 2011 204 estate in today which the pipes are completely rotten on.

We always replace them using cupro-nickel brake pipe, which has the same working pressure as steel and then paint them with some under guard.

If anyone is reading this, in no circumstances should copper pipe be used, its working pressure is not high enough for MBs ESP working pressures, especially if the car has SBC, which holds 60bar of pressure per calliper.

 

[LostKiwi]

Copper also work hardens and over time can fracture if there's any vibration of the pipe. In some countries copper brake lines are banned.

 

[Uncle Benz]

Good advice re copper pipes. We too use cupro-nickel which we make up in house, the old fashioned way

If you are lucky enough to have a nearly new car, I recommend using a wax spray product, I prefer Comma Wax Seal. If you apply it to your brake pipes annually, including the tube nuts, you will never have to replace your pipes. This has been part of our tailored service regime for twenty years now.

 

[alexanderfoti]

Good advice re copper pipes. We too use cupro-nickel which we make up in house, the old fashioned way

If you are lucky enough to have a nearly new car, I recommend using a wax spray product, I prefer Comma Wax Seal. If you apply it to your brake pipes annually, including the tube nuts, you will never have to replace your pipes. This has been part of our tailored service regime for twenty years now.

We do the same, the MB pipes come as one long piece anyway so it ends up being easier.

we swear by Dynax UB, OR ACF 50 if its going somewhere under the undertrays that is not structural, like rad support brackets etc.