Brake Problems Brake Fluid ABS Brake Pad Materials
What about those Brakes?
The braking system on our cars is often ignored until a problem crops up. Here are the most common signs of brake problems.
· Poor braking performance, hard to stop the car
· Squealing or grinding noises during braking
· Pulling to one side, or grabbing
· Loss of brake pedal
· Pulsation of the brake pedal during braking
· Clicking noises during braking
· Excessive drag during acceleration.
Here are some of the things that can cause those
symptoms.
Glazed brake pads and/or shoes: The brakes have been heated up to the
point that they become hardened and are no longer effective at grabbing
and stopping the rotation of the brake drum or rotor. This condition
usually occurs after the brakes have been overused, either because of
excessive panic stops, riding of the brake, lots of city driving
or in some cases living on a steep hill can cause this. The braking
material must be soft enough to wear and grab hold of the drum or rotor
to stop the car. Excessive overheating hardens the braking material
beyond its ability to do this. This condition can cause the brakes to
make all kinds of noises, from squeaking to grinding.
It will also reduce braking performance.
Oil or grease-soaked brakes can cause pulling, grabbing and noises. Oil from the rear differential or front transaxle can get on
the brakes from an oil seal that might have failed. Grease from a failed
rubber boot on a front end component (such as a ball joint or tie rod)
can find its way onto the brakes and cause this symptom as well.
Loss of power assist from the power brake booster is another cause
for poor braking performance. It can occur due to a loss of engine
vacuum, or deterioration of the vacuum brake booster diaphragm. This
condition causes excessive pedal effort.
Worn out brake pads or shoes. This can cause squealing or grinding noises coming from the brakes
along with poor braking. Sometimes the brakes wear away and you're into
the metal without any noise though. That is why it is good to inspect
them periodically.
Pulling or grabbing to one side can happen for a number of reasons.
Pulling can occur from mis-adjustment of the brakes, a bad caliper or
wheel cylinder, hydraulic problems, mis-matched components, brake fluid leakage, frozen emergency brake cables, or oil or grease
leakage on the brake shoes or pads.
Loss of brake pedal usually is a result of bad master cylinder or brake fluid leakage due to
failure of a brake hose or rusted metal brake line, worn wheel cylinder
or brake caliper or possibly an ABS problem. This is a very dangerous
condition and the car should be towed.
Pulsation of the brake pedal or vibration
when braking is usually caused by warped rotors or rotor thickness
issues.
Heat
and mechanical wear thin out the brake rotor, or drum, causing warping.
This warping translates into a pulsation (up and down motion) of the
brake pedal or vehicle vibration while applying the brakes. Re-machining or replacement is
the answer in this case. This condition can cause noise, excessive
caliper wear and poor braking when the condition gets severe.
Clicking noises during braking is usually caused by a brake hardware or
installation problem. The disc brake pads are held in place by pressure
from the caliper against the brake rotor. The factory installs
"anti-rattle" devices to stop movement of the brake pads, which will
stop the clicking noise. These devices are made of spring steel and over
time become brittle and break, allowing the brake pad to loosely ride in
its seat, causing rattling.
Excessive drag: Brakes not releasing can cause this problem. Sticking or
seized caliper pistons, deteriorating brake hoses, sticking caliper
guides, mis-adjusted drum brakes and park brake cables frozen due to
rust or dirt buildup can cause this. Periodic brake
fluid flush and change will help avoid caliper problems, using
your park brake regularly can prevent park brake cable problems.
Have your brake system thoroughly checked regularly, so there are no surprises. You can
"head off high dollar brake work at the pass" by keeping a watchful eye
on your brakes.
Years ago it seemed like disc
brake pads lasted forever. Not anymore. Many late models eat linings quickly. So
quickly, in fact, that you may very well suspect poor quality friction
materials. The real reason is the overall design of modern cars.
The
traditional rear wheel drive car (say, an '80 Chevrolet Caprice) stopped
by means of 22-1b., well-ventilated brake rotors and large friction
area, which resulted in average surface temperatures of 350F. Also, it
had a non-overdrive transmission and a boxy body, so it slowed down when
you took your foot off the gas. The double-nickel was the law of the
land, too.
Compare that to a typical modern front wheel drive model (Chevrolet
Lumina, Ford Taurus, etc.) with 10-1b. composite rotors and average
surface temperatures of 800F. Now, you've got overdrive, V6 and
multi-valve performance and an aerodynamic design that not only lets the
car coast farther, but also cuts air flow to the brakes. Throw in 70 mph
speed limits and you've got fast wear on the brakes.
Another extremely important reason for premature pad wear is the loss of
rear brake self-adjustment, whether from corroded mechanisms or because
the driver never uses the parking brake. When the rear brakes get out of
adjustment the fronts end up doing far more than their fair share of the
stopping. So, while the original pads may have lasted 30,000 miles, a
replacement set might only go only 10,000 or so. Using the parking brake
regularly is mandatory to keep the brakes in good working order on
vehicles with rear drum brakes.
Wayne's Garage
Serving Eugene, Oregon and Springfield, Oregon's car, truck and
SUV auto repair needs since 1973.
Integrity, Quality and Unmatched Service.
