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JC Washbish: ‘Selling Better’ Has Been the Goal All Along
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By Counterman
Ask anyone what a “complete” brake job is and you’re likely to get a variety of answers. In the context of professional automotive repair, I define complete as meaning correctly done.
Why? Because the actual work that needs done to any given vehicle can vary depending on vehicle mileage, age and condition. And it can vary based on the equipment. For example, do you have access to a brake lathe? As a counter professional, you’ll have to dig into the details with your customer to determine what they need. However, there are simple guidelines to follow that will ensure you’re advising a “complete” brake job every time.
Brake Fluid, Brake Fluid, Brake Fluid
Above all, clean brake fluid is my first requirement.
It’s probably one of the most overlooked vehicle services, and most people don’t think of it as part of a brake job. It’s an afterthought only considered if they’re forced to do it. Anytime I perform brake work, the first part of the inspection is the bleeder screws. They must be able to open. No brake job is complete without flushing the brake fluid.
There’s no need to get “crazy” with it either when it’s done on a regular basis. A couple small 12-ounce bottles are plenty. Use a clean suction-bulb to remove as much brake fluid as you can from the master-cylinder reservoir, refill it, then flush fluid through until you can fit the contents of both bottles into the reservoir. Start with five strokes at each wheel until you see how much fluid is being forced through, so you equally balance the flushing from front to rear.
Contaminated brake fluid is corrosive and damaging to all the internal brake-system components, and it can cause poor braking performance. Even though every manufacturer specifies to flush it on a regular basis, it’s still out-of-sight, out-of-mind for a lot of people. In my opinion, you can’t change the brake fluid too often.
A complete brake job not only includes fluid, but also calipers or wheel cylinders in any situation where the bleeders don’t open.
Pads and Rotors
When disc brakes are being serviced, pads and rotors are at the core of the job. It’s far less common to resurface rotors than it has been in past times, and it doesn’t matter if you take that road or go with new. But the bottom line is something must happen with the rotors. “Slapping” a set of pads on old rotors is an immediate fail. The pads will never bed in properly, and you’ll only be faced with poor brake performance, uneven pad wear and unwanted noise.
The bottom line: Rotors must be resurfaced or replaced for the job to be complete. By the same token, old pads on new rotors equals an incomplete brake job.
Why would someone do this? Your guess could be as good as mine, but believe me, I’ve seen it all and I’m sure you have too. New pads and rotors bed in together. In other words, they rely on each other for proper brake operation.
Drum Brakes
If you thought there were some offenders with disc brakes, drums are often worse. For some reason there seems to be a perception that brake drums miraculously never need service, but the same theories hold true. If you’re replacing brake shoes, the job is only correctly done by resurfacing or replacing the drums.
Hardware
Hardware is anything from springs and hold-downs on drum brakes to anti-rattle clips and slide-pin boots on disc brakes. All these little pieces are important to proper brake operation. On drum brakes, even though everything may be intact, it’s also old and the springs will simply be fatigued. On disc brakes, the same holds true and even anti-rattle clips that look OK can be worn or fatigued in some manner. Luckily, most pads come with the hardware. They don’t put it in the box just for fun.
One of the most overlooked parts of disc-brake service is the fact that the pads must be able to move freely in the caliper bracket and the calipers also must be able to move freely back and forth. Most calipers (excluding fixed calipers) feature slide pins that allow this to happen. No brake job is complete without removing the slide pins, cleaning them up, lubricating them and reinstalling them with new boots when required.
It’s surprising how often the slide pins are stuck and how often brake pads are jammed in place due to rust, and the rust must be completely removed to allow free movement of the new brake pads. Stuck pins or stuck pads cause uneven and accelerated wear, dragging brakes, pulling and excessive heat buildup.
Lubrication
I touched on it already, but it’s worth a second mention. In addition to the slide pins on calipers, the brake pads require lubrication any place they contact the caliper bracket or caliper. Brake lube is specifically formulated to a) not damage or swell rubber components such as piston or slide-pin boots, b) prevent vibrations that cause noise, c) lubricate the pad contact points so they move freely in the caliper bracket and d) resist washing out.
In the case of drum brakes, the backing plates feature specific contact points for the brake shoes, which should be cleaned and lubricated. Brake shoes also require lubrication at pivot and contact points between the shoes and hardware.
Inspection
Determining what is required for a complete brake job can only be done through inspection and disassembly. It’s easy to see worn-out pads and rusty rotors through a wheel, but even when that’s evident, you can’t see anything else until you take things apart. This is when you inspect for brake-fluid leaks, seized or damaged hardware, torn dust boots and functional bleeder screws.
If leaks are found or dust boots are torn on a caliper piston or wheel cylinder, or if the bleeder won’t open, the components need to be replaced. Only until disassembly is performed during an inspection can you say absolutely what’s needed for any given vehicle. Sure, we can all look at a 50,000-mile four-year-old vehicle and say that it needs pads and rotors, and most likely those are the only hard parts it will need. But it’s no guarantee, and the higher the mileage and older the vehicle, the more likely we’ll find something else, which leads to the next category …
Recommending Parts
There’s always a way to work into the conversation of a complete brake job. The next time someone comes in and wants pads and rotors, you might ask, “Would you like me to look up caliper availability just in case a bleeder screw doesn’t open, or a caliper pin is seized?” If they’re an experienced technician, they know how often that happens, and they’ll likely say yes, just to know in case they need them, and they’ll appreciate it!
If they’re new at all this, it will get them thinking and open the door for your advice. The next thing you know, they might change their mind and decide to buy new calipers – or at minimum they’ll leave with the extra goodies they need for a complete brake job, such as brake lubricant, brake fluid, brake cleaner and some shop rags. If they get into the job and realize there’s a problem, they’ll be right back at your store.
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By Counterman
One of the more difficult things about any technology is all the new terms you seem to get hit with, and in the automotive world, CAN bus was one of those terms. The second half, “bus,” was a term we had already used for many years, primarily as “bus bar.” A bus bar was a metal strip or bar that distributed power among multiple components.
In the automotive world, even when fiber-optic turn-signal indicators mounted on the front of a fender were as high-tech as it got, bus bars were inside many components such as fuse panels and relays, and sometimes under the hood for various engine electronics.
Then computer electronics took over. At first, we just had one electronic control unit (ECU) to deal with, and it was for the engine. Before you knew it, there was a transmission control unit, then the ABS control unit (not necessarily in that order). Wiring harnesses got bigger … and bigger and bigger.
Today, a car can have as many as 150 ECUs. In addition to the familiar engine, transmission, brake and airbag control units, doors, seats, mirrors, power steering, audio systems, cruise control, batteries and charging management systems all have their own control units. And as you can imagine, that’s just scratching the surface.
As technology was taking a ride with all these systems, engineers realized there were too many wires and too many sensors. There was no choice but to get aboard the CAN bus. CAN stands for controller area network, and a CAN bus, simply put, is a common communication line that can be used by all ECUs on the network.
The various control units on a modern vehicle need to communicate and share information over this network. Here’s an example of how and why. Years ago, when you turned on the air conditioning, a simple switch sent power to the compressor clutch. Today, the HVAC control module may need to communicate with the body control module (BCM) to notify it that A/C has been requested.
The BCM in turn sends a request to the engine control module (ECM) to “ask permission” if it can energize the A/C-compressor relay. The ECM looks at current engine operating parameters and sends a response signal to the BCM, which, in turn, sends a signal to the A/C relay.
The technological features on today’s cars are nothing short of impressive. Advanced driver-assistance systems (ADAS) include features such as adaptive cruise control, forward collision warnings, high-beam safety, lane-departure warnings, traffic-signal recognition, lane-keep assistance, automatic emergency braking and traction control.
All of the associated control units are in constant communication with each other, and since many of them must utilize information from the same sensors, through the CAN bus network this is possible. Instead of an ambient-temperature sensor for the ECM, the HVAC control unit and the instrument cluster, one sensor can share its data over the network.
Some high-end vehicles have a feature called automatic brake wiping, or brake disc wiping. This feature utilizes information from a rain sensor (also used by automatic windshield wipers) that’s sent over the CAN bus to the ABS control unit. In programmed intervals, the ABS control unit lightly applies the brakes in a manner that the driver won’t notice, to clear water and moisture away from the rotors and provide maximum braking when needed. All of this is only possible thanks to the communication available over the CAN bus.
Developing the CAN bus system was no simple feat, and it took many years to complete. The requirements for automotive CAN bus communication are standardized as part of the OBD II vehicle communication standard. There have been many changes over the years related to CAN communication, primarily affecting the speed and manner in which data is transmitted. The easiest way to think about it is to relate it to the changes over the years in USB design we’re all familiar with. It’s for the same reason. They transmit data quicker.
From a service standpoint, technicians have had to become familiar with CAN bus systems. U-codes that indicate a loss of communication between modules or on a specific bus are a tool designed to help technicians diagnose CAN bus problems.
Electrical wiring diagrams reflect the CAN bus network, and there are three different types of networks – loop, star and loop/star hybrid – referred to as CAN bus topology. Being able to recognize the type of topology can help a technician diagnose CAN bus errors quicker. In today’s world, we all have to get aboard the CAN bus.
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By Mighty Auto Parts
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link hidden, please login to view appeared first on link hidden, please login to view. Four-Wheel and All-Wheel Drive vehicles have flooded the market. Look around your neighborhood, parking lots, daily traffic routes, etc. They come in the form of trucks and SUVs, many of which will never encounter off-road or inclement weather conditions that would require a four-wheel drive application. With these additional driveline components come some challenges for […]
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