Hi guys, so I’ve got a 1985 Mercedes 200 (2 liter carburetor) and the last month or so the brakes have been giving me a bit of a headache. When standing for a while the brake pedal sinks all the way to the floor, upon some investigation I saw a damaged brake line that I replaced and bled the system, a few days later the problem was back so I bled the brakes again only for the problem to come back after about 2 weeks (It came back slowly but surely, she was my daily in this time) so I went to bleed the brakes again - this time I noticed the rear brakes were fine but the fronts were dry. Passenger side I bled all the air out but the driver side is still bone dry, I checked the connection on the master cylinder and it doesn’t seem like theres any fluid going to that wheel.
I’m only a diy mechanic so I might be missing something obvious but what do you guys recon might be wrong?
Check the master cylinder isn’t leaking into brake booster. That’s how these old Lucas and FAG master cylinders usually fail. If that’s the case, replace with aftermarket ATE master cylinder.