81 300SD May need brake booster

[tyl604]

So yesterday when I hit the brakes they slid down almost to the floor. I can pump a couple of times and the brake pedal holds but it will not stop unless I push down really hard. Sounds like a brake booster instead of master cylinder to me. Actually I can still drive it if I am careful so I could not do that (I think) with a bad master cylinder.

May need one. Anyone got a good one for sale?

By the way I noticed there is some brake fluid on top of the MC but when I took off the top it was not just full to the line, it was full all the way to the top. Do not think it has ever been over-full before. Does this mean anything?

Thanks.

Also how much trouble is it to install?