Service Slants

Toyota
Brake pedal pulsation, vibration. Owners of 2000-05 Tundra pickup trucks may complain of a pedal pulsation and/or vibration through the steering column when the brakes are applied on the open road. While warped front rotors are always a possibility, out-of-round rear brake drums are just as likely a cause, says Toyota.
Start your diagnosis by taking the truck on a road test and applying the brakes a few times to confirm that the pulsation/vibration problem exists. If it does, get the vehicle back up to 40 to 50 mph and slowly apply the parking brake. Don't overdo it; you could lock up the rear wheels! Apply the brake just enough so the rear shoes engage the drums. If you don't feel the bad vibes when the parking brake is applied, the problem is in the front brakes. Machine or replace the front rotors as necessary. If a pulsation/ vibration does set up as you apply the parking brake, the problem is in the rear braking system.
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Before replacing the drums, however, check the diameter of the centering area on both rear axle shafts with a vernier caliper or micrometer, as shown in the illustration at right. The diameter should be 4.171 to 4.173 in. If it's larger than that, the drum(s) could run oblong on the shaft(s), says Toyota. Replace the axle shaft(s) as necessary.
If the axle shaft specs are on the money, that confirms that the rear brake drums are warped or out-ofround. New-design, more rigid drums with greater mass are now available from Toyota, and they go by Part No. 42431-34021. Always replace the drums in pairs.
GM Truck
Engine ping or knock, flashing MIL, misfire DTCs logged. Some 2004-05 Chevy Colorado and CMC Canyon pickups with the 2.8 and 3.5L engines (VINs 6 and 8) built on or after VIN breakpoint 58261313 may produce a pinging or knocking sound, possibly accompanied by a flashing MIL. GM says the noise occurs most frequently on deceleration after the engine reaches operating temperature, and is most likely the result of sticking exhaust valves.
To make a definitive diagnosis, hook up your scan tool and start searching for codes. If all you see on the display is P0300 (random misfire) or individual misfire codes P0301 through P0305, that confirms that the valves are indeed hanging up. Installing upgraded exhaust valve springs (Part No. 12596078) and valve stem seals (Part No. 12596994 for the 2.8L engine, 12596501 for the 3.5) should put an end to all the problems in short order.
Ford
No air conditioning. Owners of 2005-06 4.6L Mustangs may come into your shop complaining that the a/c system blows warm air. If the system has a full refrigerant charge, no fuses are blown and the compressor clutch won't engage, chances are good that the clutch has gone belly-up, says Ford. Installing a new clutch assembly and revised orifice tube, then recharging the system to a new refrigerant spec of 26 oz., should bring the cooling performance back into check. After you're done with the parts swap, you'll need to fill out a climate control information decal and affix it underhood to alert the next tech who works on the car of the installation.
Here's a list of the new parts you'll need to complete the fix:
Component Part No.
Clutch disc .........6L2Z-19D786-A
Pulley ..............6L2Z-19D784-A
Clutch coil.........4L3Z-19D796-AA
Orifice tube .......F5XZ-19D990-AB
Information decal . .6R3A-19A286-AA
Saturn
Low or fluctuating idle. Owners of 2004-06 ION Redline models with the 2.OL supercharged inline Four engine (VIN P) may come into your shop complaining of a low or fluctuating idle speed that occurs immediately after the engine is started, hot or cold. If hooking up your scanner turns up no DTCs and there are no other driveability issues noted, flashing the PCM with updated software should improve the idle quality markedly. You'll find the new software calibration on Saturn Service Stall version TIS 6.5 2006 or later.
Ford/Ford Truck
Inoperative a/c system. The air conditioning systems on some 2002-06 Ford cars and light trucks with the FS-10 compressor may not blow cold enough or may not work at all. If you attach your a/c gauges, you'll probably find that the system pressures are way below normal. Ford says a leak at the compressor shaft seal is the likely cause of the undercharge condition. Removing the clutch and installing a new-design, more durable shaft seal (Part No. F1VY-19D665-A) is the permanent fix.
Vehicles that can benefit from the updated seal are 2002 Lincoln Blackwoods; 2003 Ford Escorts, Explorer Sports & Windstars; 2003-05 Ford Excursions, Explorer Sport Tracs and Mercury Sables; 2003-06 Ford Focus, Mustangs, Taurus, Escapes, F-150s, F-Super Dutys & Rangers; 2004-06 Ford Freestars and Mercury Montereys; 2005-06 Mercury Mariners; and 2006 Lincoln Mark LT models.
Toyota
Engine runs hot or overheats. The owner of a 2004-06 Solara with a 3MZ-FE V6 may come into your shop with a complaint that the engine runs hot or overheats on the highway. If that happens, go on a road test with the customer driving, noticing where he places the transmission shifter. If he places it in "S" (manual shift mode), chances are he's got the tranny in 3rd gear. That might be okay at 30 mph in city driving, but it's hell on the open road at 60 mph because the engine will really be screaming.