Under the Hood: Monitoring your brake pads

McClatchy-Tribune Information Services

September 2, 2019

Q: My Corolla now has close to 40,000 miles and a friend told me my brakes will be worn out soon, if they are not already. How do I know?

ó Alison B.

A: This may be true, and itís easy to find out! Brake life is the result of many variables: the type of vehicle, how itís driven, the specific brake pad composition, environmental conditions, among others.

Most brake pads include a wear sensor, a metal tab that begins rubbing on the brake rotor when the padís friction material wears thin. It creates a squealing noise that is oddly more apparent at first when the brakes arenít applied. The noise may quickly alternate or be steady. It will worsen gradually to the point of embarrassment and annoyance. Vehicles not so equipped should have periodic inspections!

Checking brake pad thickness, at least a rough estimate, depending on wheel type, may be possible by simply looking through the wheel spokes with an angled inspection mirror. Better is a close look as the tires/wheels are removed for rotation. Color-coded thickness keys are often used to demonstrate remaining pad thickness to the consumer.

The friction material on a new brake pad is typically about 8-12 millimeters thick, and those that are ready for replacement are worn down to about 3 mm. Itís important to replace the pads before the friction material wears out completely, as the padís steel backing will begin scoring/damaging the brake rotor if contact continues.

When brakes are to be serviced, there can be many opinions regarding what should be done. If the brake rotors are in good condition (sufficient thickness, smooth surface finish) and no pulsation has been observed when slowing, a simple pad replacement is usually sufficient. If the rotors are scored or pulsation is evident, they can usually be resurfaced, if remaining rotor thickness is adequate. Many shops simply replace them, as parts prices have become quite reasonable. The downside here is a cheap rotor is nobodyís friend. Iíd prefer a slightly imperfect original rotor over an inferior quality replacement. Or insist on a mid grade or better replacement. Same goes for pad quality!

Other brake services may be offered/pushed as well, such as caliper replacement, or installing whatís known as a ďloaded caliperĒ which contains new pads. I believe this to be overkill unless the vehicle has many miles or caliper leakage or stickiness has occurred. Flushing/renewing brake fluid is a good idea in any case perhaps each 4-5 years or sooner if specified.

Q: My windshield washer stopped working. The wipers are fine, just no spray. How hard would this be to fix?

ó Gene T.

A: This may be pretty simple to fix, depending on your make and model.

If both washers stopped at the same time, itís unlikely the spray nozzles are clogged. And since the wipers work, the fuse should be good.

Was any service recently performed under-hood? If so thereís a chance the washer hose somewhere between the pump and nozzles became kinked or disconnected.

Can you hear the washer pump run, and/or does a puddle appear on the ground beneath the vehicle? If not the pump is likely faulty. This cylindrical component is usually plugged into the side or bottom of the washer fluid reservoir. Depending on make/model, this could be a $20 part and possibly pretty simple to renew. If itís a more expensive part or access is poor, testing at the pump for a viable electrical command would be warranted prior to replacement.