Can anyone comment on the adequacy of flushing the brake system without turning on the ignition or running the engine at some point in the process? I am suspecting that with ABS and traction control, it would be best to open as many related solenoids as possible.

I don't believe it's at all necessary to turn on the ignition or run the engine when you bleed the brakes.

On some other makes of cars you do sometimes have to use a scan tool or the like to operate an individual soleinoid to cycle a componet if you mistakenly allow the system to drain and fill with air. I don't know if that's the case with the ML.

I think the main thing is to keep enough fluid in the system while you are bleeding it so it doesn't fill with air.

The valves are all open with the ignition off (or no ABS intervention is taking place). Bleed away!!!

Gilly

Thank you Ron and Gilly.



Geoff

I've searched through the archives and thought that I was ready to flush the brake fluid myself on my ML430. I will be buying a Motive pressure bleeder. Looks like the sequence is RR, LR, RF, LF. But, I read one thread where an ASR equipped vehicle has to have yet another valve opened, I'm a little confused on what this last one is and where it falls in the sequence. Can someone explain if I have to bleed anywhere else besides at the calipers? Thanks. -Norm

I don't believe there is any other fitting that needs to be opened to sucessfully bleed the brakes. I have had some especially spongy pedals that required some serious bleed down to get right though.

I was always under the impression the best way to really bleed the system was to actuate the high pressure return pump through the activations screen under ESP/BAS on the DAS machine. Perhaps Gilly (the man) has further insight into this?

Thanks PHAEDRUS242,

That's what I'm trying to understand, if I should just pay the dealership $120 to do it for me. I have bleed brakes on earlier model cars and must admit I'm a little hesitant with the Mercedes as I do not understand all of the intricacies of ASR and ESP. The last thing I want to do is muck it up and end up paying twice as much for the dealership to correct my mess. Yes, perhap, Gilly can offer up some advice. Thanks. -Norm

I don't know the answer to your question, but alldata shows more labor if ESP equiped. Looks like there are some additional step due to the ESP.

rene

Thanks Rene - I'm guessing that something else, in addition to the four bleeding screw on the calipers, will need to be bleed. Also, PHAEDRUS242 posted some interesting info like actuating the high pressure return pump via a DAS machine. This is beginning to sound a bit complicated. Thanks again for looking it up in Alldata labor charts. -Norm

Last Fall when I flushed and bled the brake system, I did so after Gilly, in his consistently helpful manner, advised that there would be no problem bleeding with the ignition off (see third post to this thread dated 03 10 05). I ended up with a good firm pedal after running through the bleed circuit twice in order to ensure that all the air was out.

Unless Gilly has learned something different since then, I will do the same thing next time.

Incidentally, this relates to using a pressure bleeder on a '99 320.


Geoff

Thanks for confirming Geoff. -Norm

Everything will be just fine doing a normal 4 wheel bleed using the previously mentioned order.
Esp doesn't really change anything in relation to bleeding brakes or the hydraulic circuitry, you're mainly throwing more electronics into the ABS system, such as the yaw rate, lateral acceleration sensors, and steering angle sensor, and how the ABS reacts in a sliding/turning manuever, in realtion to keeping the vehicle moving in the intended path. But it doesn't change the bleeding or fluid changing.

Gilly

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Thanks Gilly, really appreciate you confirming all this. I will be using a Motive pressure bleeder, can you tell me how much pressure I should use. I think the Motive website says something like 10-15 lbs. But I have read some posts here that say they got nothing to drain from the back even when using 30lbs of pressure! -Norm

The one I used to use I didn't really trust the gauge on it(that shows how much air pressure was being used), plus you have to remember it's simply inflating a chamber above the fluid, so I'm not sure that it's a "direct relationship" in the amount of air pressure and the amount of pressure being exerted into the hydraulic system, need a hydraulic engineer i guess to answer that. BUT a kindly word of advice is that nothing would be harmed by starting lower, say 10 to 15lb as you mentioned, and increasing the amount if you get no or low flow. Be sure to start by removing and draining out as much fluid as you can from the reservoir. You probably will never get the reservoir cleaned out of all the old gunk that accumulates in there, don't be TOO anal about it, if you worry about things like this too much, price out a new reservoir and save your anal tendencies for something useful like, I dunno whatever trips your trigger, feeding homeless children or planting trees in your community, something like that! Boy I'm on a roll this morning, aren't I!

Gilly

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LOL thanks Gilly, you made my morning. Yeah, I've been called that before, but will take your advice about the trees in my community. I appreciate the great info and explaination. -Norm