Brake Mistakes

With brakes being one of the most critical safety systems on any vehicle, brake jobs need to be done right. Here are some common mistakes to be on the look out for so you can avoid brake mistakes.

Brake repair is one of most common services performed on cars and trucks. And because brakes are so critical to vehicle safety, it’s important to do the job right. But whether you’re a DIYer or professional tech, errors can sometimes work their way into any brake job. Let’s take a look at a few of the more common mistakes and how to avoid them.

Pads/Shoes Installed Incorrectly

One of the most common mistakes made is the incorrect installation of brake pads and/or brake shoes. How can this happen? It’s actually pretty easy, especially with drum brakes. The two drum brakes shoes are different sizes. As can be seen in Figure 1, there is a leading brake shoe. There is also a trailing shoe, which is a bit smaller. If the two shoes are installed in the wrong position, the effectiveness of the drum brakes is reduced. If you put the two shoes side-by-side, you’ll see the difference in length.

Regarding the brake pads, there are usually spring clips on each pad (see Figure 2). The brake pad on the left has pointed clips that are inserted into the cavity in the caliper piston. The other pad has flat spring clips that slide over the outside of the caliper. Also, the outside pad has the wear indicator. If installed on the inside, the wear indicator can be pushed against the rotor.

Non-chamfered Pads/Shoes

While we’re speaking of brake pads, another mistake can arise from buying some aftermarket brake pads. These pads are not chamfered. Non-chamfered pads can lead to brake noise or chattering. In Figure 2, the chamfer can easily be seen.

When drum brakes are serviced and the brake shoes replaced, it is always recommended to turn the brake drum surface. But, if the surface appears to be smooth, it’s easy to assume the surface is in good shape and doesn’t need to be turned. But this can be a bad assumption. The wear area is a little deeper than the rest of the surface, which can be difficult to see.

When the new shoes are installed, the outer corners along the length of the shoes ride on the edge of the wear area. The result is an abnormal build-up of heat along these two edges, which significantly decreases braking efficiency. When the drum surface is turned, the whole surface is smooth and flat, allowing the entire surface of the brake shoe to contact the drum surface.

Another solution to this problem, if the drum is not turned, is filing the edges of the new brake shoe. Now the edges are chamfered. This will also allow the brake shoe to make full contact with the drum surface.

Incorrect Pads/Shoes

Another common problem is installing the wrong parts. Engineering changes occur from year-to-year, often resulting in part number changes. It is necessary to know the model year and make of the vehicle being serviced. For example, a 2003 model might have different pads/shoes than a 2004 model.

Also, there can be changes within a model year. On the late model minivans, two different style brake calipers are used. One is made by TRW, the other by Continental Teves (see Figure 3). These calipers are not interchangeable. Besides the use of different brake pads, the anti-rattle devices, as well as the rotors, are different between these designs. If the calipers are interchanged, brake performance can be comprised, accompanied by noise and increased stopping distances.

No Anti-Rattle Hardware

The anti-rattle hardware, basically made up of springs used to hold brake pads in place, is essential to quiet brake performance. As you can guess, not using this hardware causes a rattle, squeak, or other brake noise. Another common mistake is the incorrect installation of this hardware. Figure 3 shows that the anti-rattle hardware for the two different minivan calipers use different anti-rattle hardware. Be sure that the correct hardware is installed and that it is not installed incorrectly.

Whenever new brake pads are installed, new hardware should always be installed as well. Mopar® makes it easy with brake kits that include everything you need in one box for complete brake service. See your Mopar parts dealer for details and application listings.

No Lubrication

Lubrication is important for both disc and drum brakes. It allows for the smooth movement of critical brake parts. The lubricant that is recommended is Mopar Brake Grease, P/N J8993704, and it’s specifically designed for disc brake slides and shoe anchor plates. This product is packaged in a small, plastic tube and is available at the Parts Department of your Mopar Magazine dealer. Overlooking this lubrication is one of the most common mistakes made by DIYers when doing brake jobs.

On disc brakes, the caliper slide (the abutments on which the caliper rests) must be lubricated to allow the caliper to move smoothly back and forth. Failure to grease this area can cause rust and abnormal movement of the caliper. Wire brush the abutments and slide area on the caliper before applying the grease.

On drum brakes, there are eight spots that must be lubricated. Six of these are shoe contact areas on the support plate. The other two are on the anchor plate. Figure 4 illustrates these locations.

Rotor Problems

Two common mistakes made with disc brakes involve the rotor. The first concern is failing to turn the rotor before installing new pads. Many times, if the surface looks flat and there are no signs of heat discoloration, the rotor will not be turned. Although the surface might look OK, turning the rotor will ensure that it is smooth, allowing full contact of the pad with the rotor. Remember, an out-of-round condition can’t be seen. If the rotor is turned, you can be sure the rotor is not warped.

If the rotor is damaged, or cannot be turned because the minimum thickness has been exceeded, a new rotor must be installed. Before the rotor is packaged, it is covered with an anti-corrosion coating. This coating must be removed before the rotor is installed. This coating can cause all sorts of braking problems if not removed. Mopar Brake Cleaner is the best product for the job.

Bleed, Bleed, Bleed

The last item to discuss is brake bleeding. Whenever brake pads and shoes are replaced the system should be bled. When pressing the piston back into the caliper (and compressing the wheel cylinder), the bleeder screw should be opened to allow the contaminated fluid to be purged from the system. And after the pads and shoes are changed, the system should be bled to remove any air in the system (this is especially true if any components have been disassembled and rebuilt).