exceeder

Valve leaking that joins both sides of caliper.
Left front brake caliper 2003 e55 amg . does anyone know where to get just the valve since the caliper is fine?

Overheated

Good question. Is it even servicable or replaceable?

Todior Loci

it's not sold separately, you have to make it yourself or by a shop, it's called a crossover pipe.

Overheated

Are you talking A7/3y1 Left front seperating valve code 2514? I thought this was inside the master cylinder...if not, explains a lot. I believed the valve in the master cylinder threw the code because a piston in the left caliper was stuck.

bbirdwell

That valve is internal to the SBC unit, not the caliper or master cylinder.

Overheated

So, the valve line leading to y1 exits the master cylinder and enters the SBC where the actual valve y1 is located. This is the Traction System Hydraulic Unit A7/3 (SBC) in yours and the diagram I attached. So, when scanned y1 is producing no pressure and throws code C2514. What are possible causes? Possibly air in the system? I have a piston that won't budge on that left front caliper (which leaked fluid) and calculate that replacing it will remedy the issue. Everything worked peachy until I changed out the pads.

bbirdwell

Valves y1 and y2 are normally closed so long as the SBC system is working normally. In the event of the loss of electrical power which would cause the hydraulic pump inside the SBC to quit or if the pump inside the SBC unit fails the SBC unit will then go to a fail safe mode where valves y1 and y2 open. When those two valves are open if you literally stand on the brake pedal it will apply some manual operated hydraulic pressure to the front brake calipers only. Valves y1 and y2 are there as a failsafe so that you can attempt to get the car stopped and on the side of the road safely. I cannot say whether or not changing the brake pads would cause one of those valves to fail. I have not heard of it happening which is not the same as saying it never happens. Assuming you used a star diagnostic system when you changed out the brake pads everything should be fine. It is always possible that it just happened to pick this particular time to fail. If it is failed, the SBC unit is covered under a 25-year unlimited miles warranty at the dealership.
Somewhere in this subform is a 68 page technical document describing the operation of the SBC system. It is an attachment to at least one post on this subforum. PM me your email address and I will email you a copy.

Overheated

got it. Thanks for the note. Yes. The SBC was disconnected. We'll see what tears it's head once it's all back together.

And found the SBC doc you referenced, thanks.

Theherm

were you able to get this issue resolved? Do you know what it ended up being?

Overheated

From what I recall the boot on a piston was torn. Rebuilt it which was quite simple. The SBC was disconnected and there was no issue with the expansion chamber. Once everything was reassembled, bled the system and cleared the codes which never returned. I think the code popped up result of the compromised pressure (leak).