Yeah, we've got that

Sept. 21, 2010

Without question, the applications for specialty tools are endless—there’s always a tool for that special job at hand.

We plan on purchasing a hand-held vacuum pump to check vacuum actuators used on automotive HVAC systems. What other applications does this tool have?

For starters, you can also use a hand-held vacuum pump for checking vacuum brake boosters, vacuum solenoid valves, vacuum reservoirs and checking the integrity of vacuum control circuits. With some special adapters, you can also use a hand-held vacuum pump to bleed brakes and hydraulic clutch actuators, check the sealing of engine valves, check for a leaky heater core and scavenge air from diesel fuel filters during replacement.

We’ve always bled brakes manually without any real issues. Our equipment rep wants to sell us a power bleeder, but is it really necessary?

When anti-lock brakes came along, focus on brake fluid integrity finally received the attention it deserved. This was long overdue, considering the fine passages and exacting tolerances used in the valves and controls of anti-lock brake systems. So although the answer to your question is "yes," it’s not so much about merely bleeding a system as it is about flushing it.

During use, brake fluid breaks down over time, reducing its boiling point and the fluid also suspends contaminants within the hydraulic system. Since the hydraulic fluid moves throughout the system, these contaminants go with the fluid. This can cause hydraulic system problems if the fluid is neglected long enough. There are numerous approaches to exchanging brake fluid, depending on the tool’s manufacturer. Some use vacuum to extract the old fluid, while others push the old fluid out under pressure. The main thing is that the old fluid comes out, the new fluid goes in and there’s not any air. To find out the virtues of bleeder/flushing equipment, get a thorough walk-through from your equipment rep so you fully understand how the product works before voting with your hard-earned money.

Is there any sort of tool to determine the current condition of brake fluid without guesswork?

As a reminder, it’s always best to replace brake fluid according to the vehicle manufacturer’s suggested interval. Sometimes, however, there’s no way of knowing vehicle history so you may not know when the fluid was last changed. There are brake fluid testers available for this purpose. Some use a chemical strip that renders an identifying color when dipped in brake fluid. This color is then referenced to an identification legend to determine the fluid’s condition. There’s also a refractometer-style tester, similar to the type used for checking coolant, where you place a couple of drops of fluid on the tester and then read the condition through the tool.

Our state has a safety inspection program and we periodically get vehicles with their headlamps out of alignment. Can we just align the lights by shining them on a garage door and taking measurements?

Although states usually publish information on aligning headlights by taking measurements, your best bet is to invest in a headlamp alignment system. With the right equipment, you can perform this task quickly on a multitude of different makes and models without a lot of setup hassle or time.

We want to incorporate fuel pressure diagnostics into our drivability work. We don’t want to go overboard, since we only work on certain makes of cars. What’s the best way to get started?

Fuel pressure is a vital sign of engine performance that simply cannot be underestimated. Despite its importance for good performance, it’s often overlooked during a diagnostic scenario. Fuel pressure should always be checked when checking out any performance-related issue. Fuel pressure readings can help you determine if there’s a bad fuel pump, fuel pressure regulator or to isolate a bad injector. Depending on the system and the test procedures for it, fuel pressure readings can also provide important information about other fuel injection components.   

Fuel pressure gauge kits come with various adapters and fittings designed to fit the fuel injection systems of domestic and import cars. Although domestic cars typically have test ports so you can quickly connect a gauge, this is not always the case. As a reasonable starting place, look for a kit that has a gauge and other main components that you can add on to. That way, your equipment investment can grow along with the types of cars you service.

We periodically encounter vehicles with performance problems resulting from restricted exhaust systems. What sorts of tools and techniques are there to help us pinpoint these problems?

Although a vacuum gauge can be used for detecting exhaust restriction, it leaves a lot of guesswork with regard to just how restricted the system is. For that reason, it’s best to take a direct reading from the system itself. This can be done a couple of ways.

The oxygen-sensor mounting hole offers one handy port to check backpressure. Since all sensors use 18mm threaded holes, one adapter fits all cars equipped with oxygen sensors. Install the adapter in the hole and tighten it according to the manufacturer's torque spec.

You can also tap into the exhaust system with a universal backpressure kit. Unlike tapping into the oxygen sensor hole, this kit lets you tap into the exhaust system anywhere, including ahead and behind the converter or muffler, without removing any parts. Also, by checking backpressure ahead and behind suspected restrictions, you can cut the time spent pulling off sections of the exhaust system to isolate the source of backpressure. Generally speaking, you should see no more than 3 psi (02.1 kPa) of backpressure on your pressure gauge.

We have an old starting, charging and battery system tester with a carbon pile load device that needs repair. From what we’ve learned, this type of tester is now obsolete. Is this true?

Obsolete may be too strong of a term, since carbon pile load testers still have their place for load testing batteries. The real issue is that there’s a more efficient way to perform electrical system tests on a day-to-day basis. Today, the conductance-type electrical system tester is, by far, the most popular. This handheld tester simply clips to the battery and you follow the on-screen prompts to perform the various electrical system tests. In only a matter of minutes, you can gain full insight into electrical system operating condition. Since the learning curve to use this tool is small, you can begin making money faster with this new technology as opposed to older-style testers.

When performing any work that requires disconnecting the battery, the electronic memory becomes erased, causing a major headache for our shop and an annoyance for our customers. In some cases, it even triggers the security lock for the entertainment system, a real hassle to reset. Is there any sort of tool we can use to prevent the loss of electronic memory?

Yes, there are memory savers available from several companies that work a couple of different ways.

One style simply plugs into the lighter socket or power outlet with an adapter to maintain battery power to the electrical system. Be advised, however, that on some vehicles this circuit is not “hot” at all times. Rather, this circuit is controlled by the ignition. If you happen to connect a memory saver to this type of system with the key off, you could be fooled into thinking that the memory will be saved. So keep this in mind.

The other type of memory saver connects to the vehicle’s Diagnostic Link Connector and provides power through that gateway. Make sure the memory saver you’re considering can connect to the types of cars you service.

I often need to connect a multimeter in one area of the car, but need to observe the readings from the meter in a different area. I usually don’t have a helper available, so are there any tricks I can use in this situation?

Multimeters often have range-setting tones that you can apply to emit an audible tone so you can hear when a certain measurement threshold has been met on the meter. However, if you really need to see the display itself, this can be tricky. At least one multimeter manufacturer now offers a multimeter with a removable display head. You simply make the connections with the meter where you need to, then take the display head to a different location.

Next time we're going to cover leak detection. Until then, keep your questions coming.

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