Niagara Gazette

September 5, 2013

TOM'S CORNER: Tackling the typical braking system problems

By Tom Torbjornsen
Niagara Gazette

Niagara Gazette — Recently I had to travel to New York City for business. I couldn’t believe the brake problems I heard and smelled (yes smelled!) while on the roadway. The problems ran the gambit of grinding, burnt brake material smells, squealing and chattering.

This experience inspired me to write a column outlining exactly what these symptoms mean, so that when they arise, you can be proactive and take care of the problem before it becomes a real safety risk and extreme cost.

Grinding

When brakes grind, they have already gone beyond the first stage of needing replacement. Brake systems are set up with what are called squeal sensors. These are spring steel tabs that, when in contact with the rotor surface, generate a high-pitched squealing sound (alerting you that the brakes are low and need replacing). If ignored, the brake material wears beyond squealing to the final stage, grinding. Grinding indicates that the braking material has worn away and is now into the metal backing of the brake pads. The metal backing is grinding into the rotor’s metal face. This is dangerous and very expensive, if grinding is evident when braking, get to a shop immediately and have the brakes checked!

Pulsating

If you feel the pedal pulsate when braking (ride up and down against your foot), it means the brake caliper is sticking and not releasing the brake when you take your foot off the pedal. What’s happening is the caliper is staying clamped tightly and keeping the brakes applied on the brake rotor causing it to heat up. Over time, the heat causes the rotor to warp. The warpage results in pedal pulsation. In such a case, the calipers need to be freed up, cleaned, and the slides lubricated to get them moving again. Sometimes the rotors can be resurfaced but most times they must be replaced because they don’t have sufficient metal remaining to pass safety standards.

Chattering

Brake chattering occurs when brake pads or shoes rattle from bad anti rattle clips, worn return springs or misshapen pad or shoe backings. When the brake is applied, you hear a metal chattering and usually the brake pedal pulsates. If this is happening on your car, have the brakes checked as they could fail in a panic stop situation.

Hot burning grease smell coming from wheel

I smelled a lot of this when I was in NYC. A burning grease smell usually indicates that a wheel bearing grease seal is worn out and either wheel bearing grease or differential lubricant is leaking past the worn seal and onto the brake friction material. In the case of this problem, not only the seal need to be replaced, but the brake pads or shoes that are soaked with lubricant also because the lubricant has impregnated the friction material and this cannot be cleaned. Oftentimes any rubber seals that get contaminated with lubricant also must be replaced because the rubber gets gummy and swells, so it’s unable to do its job.

Smoking hot wheel

Years ago when I was with Channel 4 (before I started the TV show on WBBZ this year) our weekend meteorologist came to me concerned that there was something wrong with her Nissan Xterra. Seemed she smelled something coming from a front wheel after she parked the truck. Yes something was burning all right … the left front brake caliper was seized and smoke was billowing from the wheel. When a brake seizes like this it causes the brake fluid inside the system to burn or scorch, rendering it useless because it loses its hydraulic properties. If a pair of wheels getting hot on the same axle then it could be a frozen emergency brake. What happens? Due to exposure to the weather elements, moisture sets into the cables for the e-brake, then one day the person sets the e-brake and the cable is pulled tight against the corrosion and gets stuck in the applied position. As the saying goes with respect to the e-brake “If you don’t use it, you lose it!

Brake fade

In this condition, when you apply the brake (try as you might, pressing down very hard on the pedal) you cannot stop the vehicle. The other sign of brake fade is when you are sitting at a stop light waiting to merge into traffic, and even with steady downward pressure on the brake pedal, it travels to the floorboard. What is happening? The master cylinder is leaking brake fluid internally.

Brake squeal

If your brakes “squeal like a pig” when you press the pedal, it could be an indication of glazed brakes, a condition where the brake friction material gets hot and forms a smooth, hardened surface. The other cause for this condition could be worn out brake pads that are scratching the rotor face, making the squealing sound. If you catch the problem at this point, you will save a lot of money in rotor replacement.

Sudden loss of brakes altogether

When you lose brakes completely it’s usually due to a major hydraulic leak. Either a line has blown, releasing the brake fluid, or a component in the system has a major leak. Should you experience this, park the vehicle safely and call a tow truck. The vehicle is not safe to drive.

ABS brakes operate on dry pavement

This is a condition where the culprit is either a bad wheel speed sensor or the hydraulic control unit has gone bad. The system “thinks” that a wheel is locked up so ABS kicks in to correct what it falsely “sees.” In this case, the system’s braking control module must be accessed via a hand held diagnostic scan tool. If there’s a problem with a speed sensor or the braking computer it will show up in the diagnostics.

‘Til next time ... Keep Rollin’

“America’s Car Show” with Tom Torbjornsen airs 7:30 p.m. Wednesday, 9 a.m. Thursday and 11 a.m. Saturday on WBBZ-TV.

"America's Car Show" with Tom Torbjornsen airs 7:30 p.m. Wednesday, 9 a.m. Thursday and 11 a.m. Saturday on WBBZ-TV.