Pre-trip checkup: Inspect these systems before that first spring trip

John Johnson writes:  I’m hoping to take my ’72 Datsun 240Z for its first road trip in the spring. Is there a pre-trip routine you go through to help make a car dependable?

Although anything can go wrong in a vintage car, the problems that strand you are actually pretty predictable. In fact, the main issues that cause you to go from living the dream to being on the cellphone in the breakdown lane stem from failures with ignition, fuel delivery, cooling, charging, belts, clutch hydraulics, and ball joints. Address these things and you give yourself a pretty good inoculation against trouble.

The ignition systems in most pre-1980 cars have points and a condenser. Over time, the point gap closes due to pitting of the point faces and wear of the nylon block that rides on the distributor’s cam lobes. Do a dwell measurement and, if necessary, adjust the point gap to set it to spec. Make sure the distributor cap isn’t cracked and that the plug and coil wires can’t easily be pulled out of their connectors.

Fuel delivery issues are commonly caused by a bad fuel pump (I always carry a spare), but a thorough fuel system inspection should include replacing any rock-hard or very soft fuel lines and checking for rust in the gas tank, which can cause the fuel filter to clog up.

Cooling system problems come in two forms: leaking and hot running. Leaks typically come from split hoses, failed water pump seals, or cracked reservoirs. Squeeze all the cooling hoses. If they’re too soft or too hard, replace them. Rock the fan fore and aft to check the water pump bearing. If there’s anything other than the smallest amount of play, replace the pump. If the plastic fan is 40-plus years old, replace it, too. Hot running occurs when a leak-free system runs in or near the red part of the gauge. If you’re going to be driving in hot weather, test it in hot weather. If the water pump is turning and the thermostat is open, overheating is usually due to an inadequate radiator and fan.

The charging system—the alternator and voltage regulator—should charge the battery at about 13.5–14.2 volts with the engine running. An $8 cigarette lighter plug-in voltmeter is handy for verifying correct operation. Inspect all the wires to the alternator for corrosion and breakage. If you have concerns, throw a spare battery in the trunk, as a vintage car can run for hours off a fully charged battery.

Because there’s often a single belt running the water pump and alternator, a malfunction can cause those two crucial systems to fail. Inspect the belt, replace it if cracked, and check that it’s tight, deflecting about half an inch under thumb pressure. Also verify the pulleys it runs are parallel, as alternator bushings can degrade, causing the alternator to cock and the belt to slip.

Clutch hydraulics—the master and slave cylinder—can be surprising failure points. You can inspect the cylinders for signs of leakage, but the best approach is prophylactic replacement—or traveling with spares. Any steering or front suspension component can fail, but it is the ball joints that take the pounding from potholes and allow the front wheels to turn. And if one fails, you lose control of the car. Check for play by squeezing them with a large pair of channel-lock pliers.

Are all pre-trip boxes ticked? Excellent—now go drive!