Bran

Hello everyone,

this forum has helped me a lot so far, but now I need your opinion on something. I couldn't find anything related about the problem I am experiencing with 2004 ML350.

I would appreciate any suggestions

I recently bought 2004 ML350 and found out some strange things happening with ESP and traction control. I also owned 2000 ML320 for couple of years and I am very familiar with the vehicle.

There are no lights on the dash, and no codes read with my basic OBD scanner.

The issue arises when you want to play with the truck trying to slide back end on slippery road with ESP off. ESP or traction control intervenes and it brakes, I would say wrong wheel as it doesn't correct the movement, it just amplifies the slide of the rear end, and cuts the power completely until the truck is stopped. Also it happens when you want to spin all tires in snow or ice from stand still. Usually truck doesn’t move, ABS works constantly and rear one tire is spinning. As a previous owner of ML320, I know this is not normal.

My only suspicion is that whoever previously worked on the car switched the brake lines for rear wheels as I can see rear brake lines have been changed recently but looks like a very sloppy job. Which means ESP is sending brake power to the wrong wheel. As it's very dangerous to drive like this, I am thinking of switching two brake lines at the ABS pump and testing it.

What do you guys think? I don't think there is a problem with ESP module or any sensor as it would trigger lights on the dash, right?

As I haven't ever done anything around brake lines, is it safe to switch the lines at the ABS pump, and do I need to bleed the system afterwards?

Thank you very much!

Maj. Dundee

Before you do anything like switching lines, trace yours to the diagram above.

Also understand that you will need a scanner to read ABS/Traction codes, some of which do not turn on the CEL.

Bran

Thank you for the picture. I'll try to do it tomorrow

Bran

I just followed brake lines from back of the vehicle as Maj. Dundee suggested and I confirmed my suspicion. Purple line (right rear wheel) from the pic bellow is connected to ABS pump to the port closer to the engine. That is supposed to be for left rear wheel, as per picture.

So, in one of the next few days I am going to switch brake lines at ABS pump. Is there gonna be a lot of pressure in the lines and how much fluid am I gonna loose? Just so I know if I need to buy brake fluid prior to the procedure.

And, do I need to bleed the brakes afterwards?

Thanks

Maj. Dundee

Yes you must bleed the system.

AleksanderJaksa

Did you ever found solution? I'm expirencing similar problem...

Bran

Yes, lines were switched at the ABS pump for the rear wheels. I guess who ever owned this car before, they were changing rear brake lines and connected them the opposite way at the ABS pump.

This is very dangerous as ESP thinks it is braking left wheel for example, but in realty right wheel brake is being applied.

AleksanderJaksa

I agree, it is very dangerous. I'm wondering how that system does not recognize failure due to deviance in wheel speed after brake is applied on certain wheel. Anyway I will check today and post results.

BR
A