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Mr. Green Car: Maintaining your older vehicle: Brakes–part two

May 19, 2010

The caliper squeezes the pads against both sides of the rotor. The holes in the rotor reduce weight and provide some cooling. Not all rotors are ventilated. Here you can look at the pads, and see as I did on my Honda, that they are nearly worn out. My rotors are warped and need replacing, too. Time for a "brake job." Photo by Allen Penticoff

Editor’s note: The following is the second in a series. Part one appeared in the May 5-11, 2010, issue.

By Allen Penticoff
Free-lance Writer

In my last column, I began a description of how the brake system works. I described how brake fluid works and discussed the need to maintain your brake lines to avoid failures. This week, I’ll get into more ordinary brake maintenance that could save you some money by knowing just how much work is needed.

I wish I did not have to write this sort of article, one that says “beware your mechanic.” I find that most repair/maintenance shops are honest, but there are just enough greedy people/businesses out there that one must know what you need before you get there, or they’ll take you for a ride—and not in a nice convertible. It has happened to me. I’ve gone in for a simple tire rotation, only to be told my brakes were all in need of changing, and I might want to replace the tires, too. No thanks, just rotate the tires. You can bet I’d never darken their doors again. On the other hand, I’ve had many shops do work for free, so it all depends on luck, to some extent.

A disc brake and caliper. The disc or rotor will rust very quickly, but that is normal. The pads will scrape off the rust. Photo by Allen Penticoff

There are two types of brakes. The “disc brakes” that are commonly found on the front of newer vehicles, and “drum brakes” that are found on the rear axle of many vehicles. Some vehicles have disc brakes on the rear as well—I’m even seeing disc brakes on bicycles. Disc brakes perform much better than drum brakes, but are a bit more expensive to manufacture. Since the rear brakes have much less work to do, the lower-performing drum brakes are used there. The rear brakes, drum or disc, may last three times as long as the front brakes, so be leery of anyone telling you all the brakes need replacement at once. It can happen that this is needed, but they better be ready to show you the wear/problem.

Both styles of brakes have friction materials that wear out from use. “Pads” are used on disc brakes, while “shoes” wear on drum brakes. The pads and shoes are not expensive in themselves. There are three performance/quality levels to the pads, and sometimes two with shoes. The organic style is least expensive, wears the quickest, and is the dirtiest—older ones contain asbestos, and create asbestos dust that must be carefully handled when doing brake work. Next are the mid-priced “semi-metallic” pads and shoes that wear longer. Most mechanics consider the semi-metallic style to be the “standard” for replacement, and is probably what you’ll be quoted or buy unless you want or need the last style, which is “ceramic.” Ceramic style pads are the highest performing. Holding up well to abuse and high heat, they also produce the least brake dust, thus keeping your wheels looking better longer. If you have aluminum wheels, you may have noticed black stains on them—that stuff is not only dirt, but brake dust. It can be hard to remove, so the ceramic pads really help in keeping them clean. The cost of ceramic pads is not great, especially considering the extended useful life and cost relevant to the job. As an example, pads for a 1992 Honda Civic are: organic $14-$16; semi-metallic $14-$20; ceramic $33-$60.

Parts for my VW project showing the inside of a new drum, the curved "shoes" and the "wheel cylinder" between them that pushes the shoes against the inside of the drum. Photo by Allen Penticoff

I’ve been switching all my disc brakes to ceramic pads, particularly when I feel a pulse in the brakes that tells me the rotors (discs) are becoming worn and warped. It is considered better to have new rotors with new ceramic brakes; however, with organic and semi-metallic pads, there is no need to replace the rotor unless it is worn below the manufacturer’s dimensional limits or they are warped. Warped rotors are not uncommon. The sure sign of warped rotors is a pulsing or jerking feel as you brake to a stop. If you have no such feeling, don’t be sold rotors. In the olden days, the rotors would be turned down smooth on a lathe, but with the rise of cheap auto parts, most are simply replaced. Usually, replacing pads is an easy, do-it-yourself project, and rotors are generally not difficult to change, either. You can tell you need pads (or shoes) if the brake pedal needs to be pushed further or needs to be “pumped up” once to get full effective braking. You can also remove the wheel, look at the pads and judge their thickness without any more work. If you wait long enough, a small metal warning tab will begin rubbing against the disc and make an awful scraping noise when you apply the brakes. You are not damaging anything, but you don’t have much longer before the pad will be gone. Pads come in complete sets for both front wheels (all should always be changed together). Brake “calipers” don’t wear much and rarely leak. If replacement is recommended, ask why.

Drum brakes have no such warning. If the lining on the shoe wears out and the metal scrapes on the drum, it will damage the drum. Drums can be turned smooth again for relatively low cost—though in some cases replacement may be less expensive. The only way to know if drum brakes are worn is to look at them. Some vehicles have little inspection ports on the back side of the brake so you can look, but the best way is to have the wheel and drum removed. Ask what the thickness of new is compared to the recommended replacement thickness. Remember, a little goes a long way on rear brakes.

While disc brakes are fairly easy to renew yourself, drum brakes are something of a complicated mess. They have all these dirty springs and clips to deal with. It is not hard, but it is not fun, either. Be careful not to breathe the dust. Drum brakes sometimes require manual adjustment, but most have automatic adjusters that take up the wear slack whenever you apply brakes in reverse.

Other problems that can arise with brakes are a leaky wheel cylinder in a brake drum, or the brake “master cylinder” can have an internal leak that causes a loss of brake pressure. The mechanic should show you fluid dripping from the rear brake to justify this. Fluid-soaked brake shoes must be replaced. The master cylinder is an unusual problem, often noted by the need to pump the brake to stop. Air in the lines can have a similar feel, but if in pressing the brake pedal hard while stopped, it slowly moves to the floor, you’ve got a leaking line, wheel cylinder or master cylinder—get it fixed, now.

Dirty rusty drum brakes, springs and all. Must work around axle hub. Photo taken at salvage yard. Photo by Allen Penticoff

In wrapping up, you can have your brakes inspected, get a quote, and then go home, get on the Internet at one of the parts stores’ Web sites and price out the parts. All repair shops mark up the parts they sell you as it is how they stay in business and make their boat payments. The quality of part may be different as well. They likely won’t choose the cheapest parts, but you can get an idea of whether you are being gouged or not. The Web site is a good place to check out quality and features as well. At the parts counter, I often ask what is the best quality part and go with the recommendation of the counterperson—they know, they see what gets returned most frequently and hear customer complaints.

With proper and timely care, your good old car should last you a lifetime.

From the May 19-25, 2010 issue

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