83 300sd Brake issue.
 

Hello again!! I have yet another problem I'm trying to take car of with my car and wanted someones advice. My brakes DO work but not as well as when I got the car. Before i would brake and it would brake well. Now when i brake it brakes a little then the peddle gets VERY hard and I have to push HARD to get it to continue breaking. Im not loosing fluid and my brakes ARE properly bled. From what I've studied that means there is a vacuum issue? If thats true where should I check for leaks the brake booster seems to be on tight and all the hoses that connect to it are present and holding vacuum "I tested by pulling a vacuum on the tubes to ensure they held vacuum". Does this have something to do with the big thing the master brake cylinder sits on? Any help is GREATLY appreciated! Thanks!!!

The big thing the master cylinder is bolted to is the booster. It uses vacuum on one side of the diaphragm inside to help you push the brake pedal much harder than you normally could. If the diaphragm inside is torn, it will leak vacuum out and then it will not function like it should.

What you'll need to do is check the vacuum level at the booster as the car is running and the brake pedal is pushed. If you see the normal vac level (22" of Hg) drop to a very low reading, you have a torn booster.

^ Yes, connect a gauge/mity-vac type of device to one of the two orifices, block the other, start the car, take a reading.
Do this for both, you may find one is 22 inHg and the other is closer o 15 inHg, this is normal.

You want the higher pressure orifice to go the door locks, HVAC and other consumers.

The lower value one should be go to the VCV.

THANKS more testing time ^^. This forum is full of so many helpful people I can't thank everyone enough.

You're welcome, lets know how things go.