1968 Power Booster

[Duker]

I guess before I started this thread I should have asked
What are the signs that your booster is starting to go? I have too many opinions up here.

My brakes do feel too soft. This I have been told. Yet another person tells me that is not the sign of a failing Booster. It's when you can't put pressure on the brake pedal it's hard.

Can someone please tell me.


Duker

 

[robert campbell]

One sign is the idle picking up RPM when you step on the brake. That means the vacuum booster has failed.

Second is a very hard pedal to push. The easy way to check it is to stop on a slight hill with NOTHING in front of you. Turn the engine off, roll slowly forward and see if you feel like you need to push the pedal through the firewall to stop!! If the pedal effort is "way harder" than with the engine on it is working, ok.

But if you have a symptom like the idle change, it is failing and can have a somewhat harder pedal. The second test is for total failure.

Soft pedal is usually an old master cylinder. Or air in the lines. If you let you master cylinder go “dry” and fill it up, it could have air in the lines and just need to be bled. Try bleeding the system first.

The main cause of vacuum booster failure is the back seal on the master cylinder is leaking “into” the vacuum booster. The rubber in the vacuum booster does not like brake fluid. You keep topping off the master cylinder and you see no leaks under the car! Brake fluid is in the booster!!

Same symptom can happen on a non-power car. You keep filling the master cylinder and it leaks down the inside of the firewall under the rug!! Nothing on the floor!

Rob

 

[Mosesatm]

<snip>
You keep filling the master cylinder and it leaks down the inside of the firewall under the rug!!

Rob

That was an option in '68. It's the Interior Floor Rustproofing" system.:wink:

 

[Duker]

Well, I will check these options the air in the lines was brought up.

Fluid being used for my rust repellant idea on the drivers floor panel. NOT lol but I will check.

Thank you

I will get back to you later.

Duker

 

[robert campbell]

You have a power system, so the fluid would be vacuum assist "lubrication".....

Rob