CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

1996 Buick Century brake issue - Loss of most if not all pedal pressure in brake system

I have a 1996 Buick Century that I started having problems with tonight.

As I was driving, I pressed the brake pedal down and it felt like I lost most if not all of the pressure in the brake system and it was a bit difficult to come to a complete stop for the rest of the trip.

I admit that the system hasn’t been maintained in quite some time, but I recently filled up the brake fluid reservoir (2-3 weeks ago) after the brake dashboard light came on and the brakes worked just fine after this.

What is wrong with my car, and how do I fix it as cheaply as possible (or is it a cheap fix?)? Thank you all!

If you aren’t very familar with the braking systems then you really need to have someone take a look at it pronto. There are only two reasons you would have to add brake fluid, either a leak in the system somewhere, or the pads and shoes are worn excessively. The other thing that will cause a pedal to go down is a bad master cylinder. None of this is cheap but you have a potential problem that needs to be corrected before more damage is done.

+2 with Bing. You very likely have air in the system now because of that leak. I can understand you wanting to get that fixed cheaply but that’s a very dangerous condition.
Please get it looked at today for the sake of everyone’s children and grandchildren.

+3 to the previous replies.

If your brake light came on and you had to add fluid, then it means you have a leak somewhere in your brake hydraulic system. The brake light illuminates when the fluid pressure in one half of the system is different than the fluid pressure on the other half of the system (detected when the brakes are applied). This almost always happens when you have a leak - which was verified by you having to add fluid.

Get it fixed ASAP.

Without removing the brake lines, unbolt the brake master cylinder from the brake booster and pull the master cylinder away from the brake booster to see if brake fluid is leaking into the brake booster. If there is, the brake master cylinder requires replacement.

Tester

I’m gonna join the crowd that suggests taking it to a pro. Brakes are too critical a safety system to be experimenting with.

Has the brake fluid level dropped again and did you add anymore fluid? If you added more fluid since last night and tried pumping up the brakes? If you did that and they pumped up, but go right down the next time you try, then you have a leak. If it is a caliper or wheel cylinder, you should be able to see a trail of brake fluid from the offending part. If you don’t see any fluid trails in the wheel areas, then you need to perform the test outlined by Tester.

If it is at a wheel, that tire will probably have streaks on the inside of the tire. The streaks will radiated out from the center. It will be obvious.

FOLLOW UP UPDATE:

I tried the testing method of refilling the brake fluid reservoir and pumping the brake pedal to see if I could get any of the pressure back. What I discovered was that the fluid when I pumped was leaking out onto the pavement just in front of my rear tires on both sides of the car.

Am I correct in assessing that this is a brake line leak issue? Is this something that can be ‘Do It Yourself-ed’ or would it be more recommended to have this done by a professional? Thanks once again…

I’d not only have it done by a pro, I’d have the car towed there.

Don’t fool with this.

It would either be brake lines themselves leaking or the wheel cylinders. Either way would require opening the lines for replacement of the parts and then probably new rear shoes/pads too since they would likely be contaminated. It can be done DIY but if you’ve never done it before, probably best done by a shop. The brakes need to be adjusted and bled afterwards.

I’m with Bing. I admire your mentality of wanting to do this yourself so mean no offense by this but If you were not able to determine why you were losing brake pedal pressure, you really don’t want your first brake related job to be this.
If you have an experienced friend that works on cars all the time, perhaps ask him to show you how.

Am I correct in assessing that this is a brake line leak issue?

Possibly, but you won’t know for sure until you pop the wheels off and have someone hit the brakes while you watch to see where it’s leaking from. It could also be the bleeder screws - if someone opened them and then didn’t close them again, this would happen.

That it happened at the exact same time on both sides of the car is, frankly, suspicious. It could be an amazing coincidence, or you could have a vandal on your hands who is taking his pranks way too far.