Same thing happened to me. Even though the brake lines were not opened somehow the mater cylinder suddenly became defective. If you find on opening up the bleeders, you are unable to bleed the system, it's no doubt the master cylinder.







'91 560SEL 88,000
'94 SL500 22,000
'86 300SDL 202,000 gone

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jcciem
'94 SL5000 60,000
'91 350SDL 545,000
'91 350SD 197,000
'00 E55 AMG 77,000