Racod

I just replaced the clutch slave on my 1990 vette. I have noticed that my brake pedal is now hissing at me...kinds of like it has and air leak. It is less noticeable when the brake is depressed but very loud when the brake are not applied. Brake pedal feel and operation seems normal other wise. IT is loud enough that it can be hear over my Magnaflows!!

Can these two items be related? What is it?

hooked073

sounds like the vac hose going to the booster is leakind or you have a bad booster. The strange thing is it is not effecting how your petel feels

Racod

not at all. It just started. I did some research and came up with the booster too. Maybe I knocked something loose (vacuum line??) when putting in the slave.

I will have to take a look.

65Z01

Check to see if cruize control still works.

gerardvg

You have a vacuum leak at the rear of the booster, i have had that on my vette did not really affect the booster performance at first.
After some time i noticed the pedal getting pulled a little towards the floor when the engine ran It got worse and a new booster fixed it.

Racod

are they hard to replace??

gerardvg

Hi
Not too hard you can unbolt the two nuts to remove the master cylinder and you do not need to remove the brake lines there is enough give, remove the vacuum hose.
From inside the car remove the clip that secures the rod to the brake booster, then unbolt the two nuts securing the booster to the firewall.

From the engine bay pull the brake booster forward a bit over an inch for the threads to clear and it's out.

Try to send it of for reconditioning, if you cannot wait see below.

Below are links to corvettecentral

I do not know why the 90-91 booster is double the price of the earlier ones ?!?!?

http://www.parts123.com/parts123/yb....5Z50000050F~~~

The metal copy.

http://www.parts123.com/parts123/yb....5Z50000050F~~~

the 85-89

http://www.parts123.com/parts123/yb....5Z50000050F~~~

jv9999

The plastic shell cracks pretty easily. Just stepping on the pedal too hard can crack the booster.

Racod

The hardest part of replacing it looks like removing the under dash cover....

Cliff Harris

The hardest part is getting the nuts off the inside of the firewall. Lots of stuff in the way. My recollection is that one is easy but the other one will take some work. I think I had to use a universal joint to get in there.

Cruizin

As per post by 65Z01. Check that your cruise control is working. The brake pedal operates a vacuum switch to disconnect the cruise control when you use the brakes. There are two rubber vacuum hoses connected to the switch that if split or disconnected would most lively create a considerable hissing sound.