Look in with a flash light.......it'll be a black rubber disc the same size as the push rod base. If it's not there, it'll be metalic.

I suggest pulling the booster. I had to do it my race car with a race seat roll cage in the way. I didn't want to do it but it turned out to be not such a bad job and didn't take long. I don't think it's a good idea to install another disc with the old one still in there...somewhere.

Chuck

Here is what it looks like inside the booster on a Jan 71 Series 1 240z

Success, I left the booster on the car, Found the disc. It was in the chamber where the push rod goes. Got it out, glued to the push rod and solved my problem. Thanks for eveyones help. Blue the pictures helped alot. I would recomend everyone try this fix while the booster is on the car first. You can always remove it if this does not work.

Congrats Manny......now you're a brake booster expert. Phillip has the best illustrations to help his fellow Z buddies.

Old thread but it's a good one... I doubt Manny will read this three years later but if anyone can comment I'd appreciate it. After you removed the push rod was the seal still in good shape and reusable? Is there any place to source a new seal if necessary? I didn't see anything from MSA or from a generic Google search.

Any tips in general regarding removing the push rod or is it pretty self explanatory once I get in there? Thanks guys.

Reviving an old thread.

I have a 1973 240z with 48,000 miles that has been off the road for 7 years. (I pulled the engine to reseal it and it has sat since then.)  I am now working to put it back together this year and enjoy driving it again.

One of the issues I had with this car was the brakes never felt good. Almost as if the booster wasn't working. However, I recall doing the standard brake booster test back then and determining that it indeed work.

I pulled the master cylinder last night to check for the presence of the reaction. While it did not come out attached to the push rod, I think it is still in place at the back as it is black and feels rubbery.

Does it matter if it is attached to the pushrod for it to work?

Thanks!

Poke it, inside, with a screwdriver.  If you feel metal it fell out.  If it's rubbery it's still there.  As long it's between the rod and the diaphragm seat when assembled it doesn't matter where it started.

I don't know why they cal it a "reaction" disc.  It should be called a damper or something similar.  

 

Zed Head, thanks for the reply. It definitely is rubbery, I could feel it with my finger.

When the car is back up and running I will try new pads and rotors. Maybe my problem is as simple as old pads.