When your brake pedal sinks.

2001 Saturn SL1 : Brake pedal sinks complaint.
I found the brake pedal going to second stage and not sinking from there. Usually this is a hydraulic problem so you want to check the fluid level. If the reservoir is full, it may be an internal master cylinder problem. If the fluid level is low you may have a leak in the system.

The reservoir is empty but the area around the master cylinder is dry. We need to inspect the brake hydraulic system and look for where this fluid went.
We're looking for a wet spot. A leak at one of the wheels will usually show up on the inside of the tire.

In this case, right rear wheel.

This car has drum brakes in the rear and the fluid is coming from inside the drum so the leak will be a wheel cylinder.

The shoes have a lot of pad material but it is saturated with fluid. We'll need new rear shoes and wheel cylinders. The drum is in good shape so we'll clean and reuse. If we try to reuse the brake shoes after this fluid saturation they will tend to grab and not apply smoothly. The other rear wheel, which has dry shoes will apply differently as they no longer match. Brake shoes come in a set, replace as a set. The wheel cylinder on the left rear doesn't appear to be leaking but is the same age and conditions as the one on the right. If it isn't leaking now, it will soon be.

Now, this left side looks okay but we'll be replacing it and the shoes for the reasons I've said. I wanted to show you something else though while I'm here. Because there is no fluid visible on the outside of this wheel cylinder does not mean it isn't leaking. The leak has to get past those outer boots before it is visible. So peel the boot back and look for signs of wetness. If there is fluid inside the boot, the cylinder is bad.

Both wheel cylinders, all brake shoes, clean drums. Not finished inspecting yet either. Just as you don't want to do one wheel when both need service, you don't want to do only rear when front need service so we'll be inspecting the front brakes as well.

Pull both front wheels and inspect front disc brake pads, both inside and outside pad. No problems here.

Okay. Lets get some parts and fix these rear brakes!

Thanks!

Kenneth Hayes

khayes@ggauto.repair