My brakes suck

[frankensteinZ]

My brakes work great, after I pump them once. Just once is all it takes. I have tried to bleed them several times but the still have to be pumped. Can anyone help me?

Frankenstein Z

[Daniel]

Once again we need more specific info.Tried to bleed them?What does that mean?The better the question the better the answer.

[bryantatem]

I would try a vaccuum type bleeder. It will help keep ALL the air out.

-Don't pet a burning dog...

[Darylick]

Did you try bleeding the master cylinder, I don't know about all Zs but when I replaced brake lines on my 77 had the same problems. It's the only car I've ever bleed that has valves on the master cylinder.

[frankensteinZ]

I have never bled the master cylinder, I didn't know you could. I also heard that the brake lines themselves could be the problem. I have heard of a vaccum bleeder, but if the lines are letting air in would that still help?

Frankenstein Z

[2ManyZs]

Well, I've posted this before but you should always bleed the master cylinder before you bleed the wheel cylinders. When you add fluid to the master, if there is any trapped air when you add the fluid, it may not get all the way to the wheel cylinders when you bleed the cylinders. Therefore, you have introduced air into the system while you are trying to do the opposite, and have defeated your own purpose.

If, after a proper bleeding, you still have to pump the brake pedal, I would suspect you have a bad master cylinder, barring any leaks in the system such as a wheel cylinder or brake line.

[Daniel]

If the rubber brake lines have never been replaced or your not sure if they have--ITS TIME.If the rear wheel cylinders have not been replaced there is a good chance thats your problem.I would suggest replacement of them instead of the rebuild kits.If the brake shoe adjusters on the rear wheel cylinders is not working the first pump could be putting the shoe in proper position,the second puts it against the drum and makes you stop.When the brake is at rest the shoe pulls back to the "too far" position.Then you must double pump again.

[frankensteinZ]

Thanks for the explanation guys, I will put it to good use.

Thanks Again

Frankenstein Z

[Saint]

I've got the same problem with double pumping the brake pedal. I also have a problem which, I think, is associated with Servo unit. When the power comes off the brake pedal goes down a long way before engaing. I'm connecting this with a fault in the servo unit pressure. Would this be correct??

[2ManyZs]

Saint, has it done this ever since you got the car back?

Does the pedal firm up with a second pump on the brakes?

I'm wondering if you possibly just need a good bleeding again, perhaps there was some trapped air somewhere and it is now moved to one of the wheel cylinders and/or pistons and is causing the soft pedal. Did they bleed the master thoroughly before they bled the brakes themselves I wonder?

Most of the time, a problem with the Master Vac will cause a harder pedal due to less assist and you will be standing on the pedal to get the brakes to work, like driving a car with no power brakes at all.

When you say the brakes get worse when the power is off(idle?), I'm also wondering if maybe you just have something as simple as a vacuum leak to the Master Vac.....but that would also make it stiffer not softer...

[Saint]

Yes to both questions. Thanks for the advice though, I'll go for the master cylinder bleed and see if it improves. Cheers