Welcome to the early w123's owners group!

Now you will get to start learning all the headaches of the early years. You'll also find out it is probably a 1977 which is the first year! Would love to see photos!

Your first issue is your brakes are probably getting hot! What cured mine was a brake flush, your brake fluid is probably so dark it resembles the motor oil.....I would suck out all the fluid out of the reservoir and bleed the system. You may be due for vacuum pump rebuild, but usually what you described is because of over heating brakes or a bad master cylinder.

No heat and no air, is because you have the evil servo unit! Google it....see if you have the aluminum servo or plastic, and see if its cracked or leaking....and then I can start telling you what to do next...

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