Non - F-Body Brake Question

[Rob Bell]

Hello all, maybe someone can provide an answer for me on this one. My winter beater is a 1990 Olds Cutlass (N-body I think). I have had this car for many years and the brakes have always sucked. This car does not have ABS. The brakes seem to work "normally" except that they feel weak. However, the pedal is not soft. There is no air in the system. It's almost like there is little power boost. However, there is not a vacuum leak from the booster. I also know that boost does exist because if I deplete the vacuum in the booster, then the pedal gets really hard to push. So I'm wondering, could this be that the booster was always bad? Or would this more likely be a master cylinder problem? The car does not exhibit any abnormal behavior like pulling or odd wear on the brake pads or shoes. None of the wheel cylinders or calipers leaks. So everything seems fine, except that the brakes are weak. Any thoughts?

[FreakV6]

Re: Non - F-Body Brake Question

i would think master cylinder or possibly the brake lines themselves. as they age they will begin to expand when pressure is put through them, thus decreasing breaking performance.

[TheGr8Schlotzky]

Re: Non - F-Body Brake Question

My suggestion would be to remove the master cylinder (Just the two bolts to the booster, don't need to disconnect the brake lines or anything else). and check to see if the master is leaking into the booster. If so, you'll have to replace both. When the master begins to leak, it drips into the booster, and can ruin it as well. I had this problem on my Camaro and had to replace both.

If there is no brake fluid on the connection and the back of the master appears good, you booster may still be bad, but it would be cheaper and easier to rebuild your calipers (or buy rebuilt calipers). The calipers on my car were also worn out despite not having any leaks, and this caused poor brake performance.

[Rob Bell]

Re: Non - F-Body Brake Question

OK I'll give that a try, although the fluid level in the resorvoir has never dropped. So I doubt it's leaking. But you never know.

Is there a way to determine if a caliper is bad, given the brakes seems to function normally, except for being weak? I've had this car since it was almost new. I'm just stumped because it's always been this way. It's not like it suddenly started this one day. It stops perfectly smooth and straight. Otherwise the brakes don't have any issues.

[TheGr8Schlotzky]

Re: Non - F-Body Brake Question

If you really try, can you lock up the wheels under braking?

[Rob Bell]

Re: Non - F-Body Brake Question

If I hit them really hard, yes. But it takes a lot more effort than a normal car would.

[TheGr8Schlotzky]

Re: Non - F-Body Brake Question

In that case, your booster is more than likely the culprit.. Rockauto should have rebuilt ones with a core charge. It comes out pretty cheap usually.

[cam98aro]

Re: Non - F-Body Brake Question

does that thing even have disc brakes?

going from a disc brake camaro, to drum brakes is a HUGE difference, and that is probably what you are feeling.

i have a car without a brake booster, and i would think if your car stopped like that one does you would be afraid to drive it, you literally have to press the pedal down as hard as you can, and then it comes to a nice sloooowww stop.

[bigbrian442]

Re: Non - F-Body Brake Question

How old is the brake fluid? Brake fluid absorbs moisture over time and will make the brakes feel soft and not work as best as they can.

[Rob Bell]

Re: Non - F-Body Brake Question

Cam98aro, it has has front disc rear drums. I'm not afraid to drive it because I know how it behaves. But my wife won't touch it and it scared the crap out of one of my friends when he drove it. However, I did warn him that the brakes were not real good. If I did have to make a really hard stop though, I'm not too confident that it would do it.

BigBrian, the brake fluid was replaced about two years ago. However, this problem was always present.

Gr8Schlotzky, I'm tempted to replace both the booster and the master cylinder. There's not much else to the system.

[TheGr8Schlotzky]

Re: Non - F-Body Brake Question

If you are able to lock up all four wheels if you really slam the brakes down, then it would seem that the master and calipers/drums are doing their job. It sounds to me like you're basically driving with manual brakes. If all you need is a little power assist, then your booster is probably not up to par. I'd still check the master for leaks if you can, this could be the reason that the booster is bad.

And for the record, my Camaro was never low on brake fluid, but the master did leak into the booster which ruined it.

[Rob Bell]

Re: Non - F-Body Brake Question

OK I'll check it out. I doubt if I could lock up the fronts, I'd bet it's the rears that lock up. I'd probably have to really stand on it to even hope to lock the fronts, I haven't tried that.