I am looking for the part # for rear brake lines for 2011 E350 4matic.

 

Can you possibly locate it online ?
https://www.mbdirectparts.com/

Parts numbers are often not simple to come by

Better brake lines can be made from standard coils of soft copper sold for that very purpose.

 

There is steel brake pipe and there is rubber brake hose.
What is your definition of brake "line" ?

Here, if you car is a W212.056 , or choose your correct model. Brakes hose or pipes would be the same usually, but best to use your car model.
https://nemigaparts.com/cat_spares/e...56/d02/42/090/

#200 x 2 units and #450 x 2 units are all brake hoses. #150 and #100 are brake pipe all the way from the ABS pump to close by the rear calipers

 

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