Bad brake booster?

[ZMONSTR]

Brake pedal is very hard to push.  When the car is in idle and I push the brake pedal, it cause the idle to drop severly causing a stall or almost stall.  There is also a hissing noise down near the brake pedal when its pushed.

 

Thoughts?

[NewZed]

You are correct.

[ZMONSTR]

One more question.

 

The master cylinder is a NABCO 7/8.  I roughly measure the brake booster between 8 and 9 inches diameter .  Does this mean any 240 or 260 brake booster would be acceptable?

 

Whats on there is an after market Bendix label, made by Master Vac.    Part number is 285186.419240.  Google is absolutely no help on this part

[Miles]

Before answering your questions we need to know:

 

• What year and model Z car do you have?
• Has the brake system been modified?
• Posting pictures helps.

 

If you know the year and model (240Z, 260Z, 280Z), you can order the correct booster for your car.

 

Motorsports Auto and Black Dragon sell the booster.

 

You absolutely need to download the correct  Factory Service Manual (FSM) if you are going to own a Z car. There are links to the FSM sites elsewhere on HybridZ. At minimum, you should have a 240Z Haynes manual.  You can also Google "how to replace 240Z booster"  and search HybridZ as  booster replacement  has been posted many many times.

 

If the master cylinder is good you do not have to remove it. Just unbolt it from the booster and push it to the side. This will save having to bench bleed the MC and the rest of the brake system. Instructions for bench bleeding can be found here and on the internet.

 

Be safe. If you are not comfortable with working on brake systems take the car to a brake shop.