I recently acquired a 77 300D which had brake fluid dripping from the booster after I drove it some. I'd like to swap one from a parts car, however I noticed the 77 booster is slightly smaller than an 85 booster. Will they interchange? I will of course be replacing the master cylinder as well.

Yes. No noticable difference. Clearance from the fuse panel was the reason for change.

Thanks, Mark. I'll swap it out.

__________________
1984 300D Turbo 200K

Be careful with the newer ones. I was sent one that was listed as a correct part for 77-85 but it was for a late production 123.


It installed on the car but the arm was too long and ended up holding down the brake pedal and cooked the brakes.


Now before you call me an idiot, it all fit and seemed fine and it did work. It eventually broke the aluminum bracket that holds the pedal. So double check pedal height before you think everything is fine!

__________________
1978 300D

Just got a rebuilt booster, the 85 was shot too. I need to swap the brake pedal yoke with the old one for the pin to fit. Any idea on how to get it off?

__________________
1984 300D Turbo 200K

It looks like the yoke is attached by a small ball joint and should just pull apart like the throttle linkages on the engine, but I couldn't get it out. Probably need to tear down the brake booster completely to remove it. I'm going try sending the original booster in to be rebuilt. So I can confirm a late model, bigger w123 booster won't fit an early 123. The arm is the same length, the yoke is just different.

__________________
1984 300D Turbo 200K