2006 Tech Tips Mailbag - Page 4 | FenderBender and ABRN

Tech Tips MailbagPage 4

DiagnosticsSuper Sleuth When sleuthing driveability issues, check that the correct design spark plug wires are installed on the vehicle. When wires are replaced, only use OEM or OEM-equivalent design plug wires. Wires that are “alien” to the system design can emit radio frequency interference (RFI). The computer or adjacent sensor wiring can pick up spurious signals, and these can produce driveability and hair-pulling issues – the latter is especially problematic if you are hair challenged.Barry D. London, Owner/Technician
Omega Performance, Syosset, NYTO VOTE, ENTER 220 ON VOTING FORMCAN Bus VehiclesIf a customer comes in complaining of various faults from annoying (no power windows) to inconvenient or dangerous (no-start/quits running). This is usually when multiple but otherwise unrelated systems go down at the same time. The problem can be a simple as one bad wire. An easy starting point is to check your CAN buses (yes, all of them) for signal, shorts and power. Some new cars have stereos, clocks and compass displays on one of the buses.Jason Burr, Mechanic
4 Seasons VW, Missoula, MTTO VOTE, ENTER 221 ON VOTING FORMExhaust Pressure Test An easy way to check the exhaust back-pressure is to drill a 1/8-inch hole in the exhaust pipe forward of the converter. Use your gauge with an adapter to fit into the hole. When you’re done, you can put a rivet in the hole and the pipe is as good as new. It’s a lot easier and faster than removing the oxygen sensor.Richard Fraser, Lead Automotive Technician
U.S. Border Patrol, El Paso, TXTO VOTE, ENTER 222 ON VOTING FORMAbsolute Location of Fluid Leakage When the source of a fluid leak is in doubt, here is a way to absolutely locate the trouble spot or spots. I shampoo and dry the generally suspected area. I use a siphon-type spray gun that works off the shop’s compressed air. I fill the pot with baby powder and spray the suspected area until it is a pristine white everywhere. Then send the customer out for a test ride or have him come back the next day. The leak sources will jump in your face. I have used this trick for years. It makes the shop smell nice, too.Byron Hildebrandt, Mechanic/VW specialist
Tire Connection, Cambridge, Ontario, CanadaTO VOTE, ENTER 223 ON VOTING FORM

BrakesZap the RustTo avoid excessive lateral run-out of brake rotors due to rust or corrosion accumulating on rotor hats and hub flanges, carefully clean off all the rust with a brass bristle cup brush or other cleaning tool. Degrease the parts. Brush on a very thin coat of anti-seize compound. The zinc in the compound will act as a rust preventative and a sacrificial anode. This will also make future removal and reassembly much easier and cleaner.Barry D. London, Owner/Technician
Omega Performance, Syosset, NYTO VOTE, ENTER 226 ON VOTING FORMABS BleedingThis is not my idea, but I have read it in a few different brake service articles and it works great and saves time. When power bleeding the brakes, use a throttle pedal depressor on the brake pedal just about a 1/4-inch down. It makes it a lot easier to bleed the system.Gary Alford, Repair Leader
St. Joseph Co. Parks, South Bend, INTO VOTE, ENTER 227 ON VOTING FORMRubbing the Wrong WayWhen inspecting the brake system, always check the parking brake cable housing at any point where it rubs against a moving or vibrating chassis part. Sometimes the cable housing rides on top of or in direct contact with the constantly moving axle. The outer casing can start to wear through and damage the inner cable.If the inner cable is still intact and functional, protect the housing and cable from further damage and abrasion. Slit an appropriately sized length of heater hose and push it around the damaged area. The slit side should be opposite to the damaged area. Don’t secure the hose with a zip tie. It will hinder or restrict movement of the inner cable. Inspect your “bandage” for integrity of the repair when performing seasonal services in the future.Barry D. London, Owner/Technician
Omega Performance, Syosset, NY
TO VOTE, ENTER 228 ON VOTING FORMDrum Relief Here’s a little detail you can perform when machining brake drums. There is almost always a rusty lip that prevents easy removal of the drum. Measure the width of this “unswept” brake surface. Once on the lathe, on your last cut, machine a generous radius, much like a new drum, in this area. This will make drum installation and future removal easier. It will also help prevent brake dust buildup inside the drum (no rusty, unworn lip to hold it in).Ernie Orgar, Jr., ASE Master Auto Tech
Basset’s Service Center, Rochester, NY
TO VOTE, ENTER 229 ON VOTING FORMNecessity Is The Mother Of Invention The caliper piston can be difficult to remove when in the process of rebuilding. This can be even more difficult if the shop air compressor is temporarily down. Don’t despair. Success can be yours with the aid of a bicycle pump and the tapered accessory pump attachment. Here’s how:Place a towel in front of the piston to catch it as it exits the caliper. Remove the bleed valve, insert the tapered adaptor into the open passage and pump once or twice. Voila! Wasn’t that fun?Barry D. London, Owner/Technician
Omega Performance, Syosset, NY
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