Truck Parts Only Old Drivers Still Remember

Truck Parts Only Old Drivers Still Remember

Number 20, the air starter.

Most trucks crank on an electric starter, but some big diesels spun up on compressed air instead.

A charged tank fed an air motor that spun the engine over with a hard whoosh.

No battery to go flat in the cold.

On heavy and off-highway iron, that was worth a lot.

Most road drivers never saw one.

Number 19, the oil bath air cleaner.

Before paper filters, a truck breathed through a canister with oil pooled in the bottom.

Dust hit that oil, stuck, and dropped out before it reached the engine.

It did real work, but it was filthy to service.

You dumped the oil, washed the mesh by hand, and did it again when the dust built up.

Number 18, the wig wag.

Air brakes only work with enough air, and the wig wag warned you when it ran low.

It was a mechanical arm with a flag, hinged so it fell into your line of sight when pressure dropped too far.

No light, no buzzer, just a flag in your face telling you to stop while you still had brakes.

Low air lights and buzzers eventually replaced it.

Number 17, tube type tires.

A modern truck tire holds its own air against the rim, but older tires ran an inner tube and a flap inside, like a bicycle tire scaled up.

A nail meant the tube went flat fast, and you were breaking the tire down on the shoulder to patch it.

Tubeless tires were tougher and easier to fix.

They pushed tubes out of mainstream trucking.

Number 16, the floor dimmer switch.

High and low beams used to be a button on the cab floor.

Worked with your left foot.

You’d stomp it to flip your lights without taking a hand off the wheel.

You knew exactly where it sat in the dark.

When it moved up onto the column, a small piece of muscle memory went with it.

Number 15, the fuel shutoff cable.

A mechanically governed diesel didn’t always die when you turned the key.

The key didn’t control the fuel.

To shut it down, you pulled a cable that cut the fuel at the injection pump and let the engine starve out.

Drivers reach for that knob out of habit every shutdown.

Electronic engines took it over and the key does that job now.

Number 14, the cab-over doghouse.

In a cab-over, the cab sits right over the engine, so the motor lives partly inside the cab.

To reach it, you tilted the cab forward or pulled the cover, the doghouse, from inside with the heat in your lap.

Cab-overs ruled when overall length was tightly limited.

When length rules changed and the market favored long-nose trucks, the cab-over faded.

Number 13, the two-speed rear axle.

Some rigs carried a rear end with two ratios instead of one, shifted by a switch on the gearshift knob.

Drivers called it splitting the rears and it doubled the gears they had to work with.

Done right, it let a loaded truck pull a hill it couldn’t have otherwise.

Splitter gears mostly moved inside the transmission and the switched axle faded out.

Number 12, manual slack adjusters.

As air brakes wear, the slack has to be taken up so the brakes keep grabbing right.

On older trucks, a man did that by hand.

You crawled under the rig with a wrench and set each adjuster axle by axle and a brake out of adjustment could fade when you needed it.

Automatic adjusters became standard on newer trucks and the hand work mostly faded.

Number 11, the brownie box.

Before transmissions carried every gear in one case, drivers bolted a second gearbox behind the main one.

That auxiliary box, the brownie, multiplied the main gears and gave a loaded truck the ratios it needed.

It usually meant a second shift lever and a second hand always working.

Wide-range main boxes made the add-on unnecessary and the brownie mostly disappeared.

Number 10, the hand throttle.

Set into the dash, this knob held the engine at a chosen speed with your foot off the pedal.

You’d pull it out to warm a cold diesel without standing on the throttle or to hold steady revs for a pump or a power take off.

It gave a driver a third hand when he needed one.

Electronic controls handle fast idle now, so the hand throttle left the dash.

Number nine, Armstrong steering.

That’s the old shop joke for steering with no power assiSt. Your arms supplied the muscle.

At highway speed it wasn’t bad, but turning a loaded rig in a tight yard could be a real fight.

It built shoulders a man never asked for and it punished anyone who tried to turn a truck that wasn’t rolling.

Power steering became standard and parking a rig stopped being a wrestling match.

Number eight, the glass sediment bowl.

A clear glass bowl sat low in the fuel line where water and dirt heavier than fuel settled out before the injection pump.

You could see the muck collecting through the glass and drained it off by hand.

On older trucks and machinery, checking that bowl was a morning ritual because water in the fuel could stop a diesel cold.

Sealed filters and water separators do that out of sight now.

Number seven, vacuum wipers.

Before electric motors, many trucks ran the wipers off the engine’s intake vacuum.

The trouble showed up exactly when you needed the wipers moSt. Step on it to climb a hill in the rain, the vacuum dropped and the wipers slowed or stopped dead halfway across the glass.

Drivers who ran them remember staring through a smeared windshield on a grade.

Electric wipers fixed it for good.

Number six, the pyrometer.

This gauge read exhaust gas temperature.

On a long pull, how hard you could lean on the engine before something let go.

Push it too hard up a grade and that temperature climbed until it could cook pistons or the turbo.

Smart drivers watch that needle like a pilot watches his instruments, backing off before the heat did damage.

Modern engines pull the power back themselves, so flying the pyro became a lost skill.

Number five, ether starting systems.

A cold diesel can be stubborn and ether, basically high-test starting fluid, fires at a lower temperature.

Some trucks had a built-in system that metered a dose at the push of a button.

Others got it straight from a can.

That’s where the danger lived.

Too much or ether on an engine with a grid heater can bend a rod.

Plenty of men still reach for a can on a cold morning, carefully.

Number four, the crash box.

A modern transmission has synchronizers that match the gear speeds for you, so almost anyone can shift it.

The old non-synchro boxes had none of that.

To shift one clean, you matched engine speed to road speed yourself, double-clutching through the gears or floating them with no clutch.

Miss the match and the whole box ground like a can full of bolts.

This is the one old drivers point to.

Synchronized and automatic boxes took the skill away.

Number three, twin sticks.

Some trucks ran two shift levers side by side, one for the main box, one for the auxiliary behind it.

To move through the gears, you worked both at once by feel, sometimes with both hands off the wheel.

Done right, a driver moved through them like he was playing an instrument.

Done wrong, you were stuck on a grade with the whole rig bucking and the load pushing you back.

No computer ever shifted a truck like that.

Number two, the trolley valve.

This was a lever on the steering column that worked the trailer brakes alone, apart from the foot pedal that worked everything together.

Drivers used it to take up slack in the trailer or steady a swinging load without slowing the truck.

Used wrong, though, on ice or in a panic stop, leaning on the trailer brakes alone could help put a trailer sideways.

The hand valve faded out.

And now a driver brakes with one pedal and lets the truck sort it.

Number one, split rims.

The men who worked on them called them widow makers, and they earned it.

A split rim is a wheel built in two or more pieces, held together by a separate lock ring.

Seat that ring wrong, air it up, and it can let go with enough force to kill a man standing over it.

That’s why tire men aired them inside a safety cage, and never stood in front of one.

Single piece tubeless wheels and strict safety rules pushed them out of everyday shops.