- L -

Lead Sulfate

A hard, insoluble layer that slowly forms on the plates of a discharging battery that may be reduced only by slow charging.

Leaded Gasoline

Gasoline to which a small amount of tetraethyl lead is added to improve engine performance and reduce detonation, a practice no longer allowed due to EPA regulations.

Leadfoot

A person who drives faster than necessary.

Leading Link

A component of the suspension system that is attached to the chassis behind the wheel and positioned to resist fore-and-aft movement of the wheel.

Leading Shoe

1. A brake shoe in a nonservo brake that pivots around a fulcrum in the direction of normal drum rotation. Also known as forward shoe. 2. The first shoe in the direction of drum rotation in a leading trailing brake.

Leading-trailing Brake

A drum brake that develops self-energizing action only on the leading shoe. Brake application force is separate for the leading and the trailing shoes. Also called a partial-servo or a nonservo brake.

Leaf Spring

A rear, vehicle-suspension spring featuring one or more flat leaves of spring steel with graduated lengths. It has an "eye" at one end to connect to the vehicle frame and it is connected to the axle with a U-bolt.

Leaf-spring Bushing

Bushings that are used to damped noise and vibration from the road to the frame of the car.

Leaf-spring Center Bolt

A bolt passed through a hole in the center of each spring leaf for holding the leaves together. The bolt head is used to locate the spring position on the axle-housing.

Leaf-spring Hanger

The vehicle frame-attachment bracket for the front eye of the rear leaf spring that allows the spring to pivot.

Leaf-spring Shackle

The small arm, or swing attachment for the rear of the leaf spring located between the frame and spring eye. It allows the spring to shorten and lengthen during normal driving conditions.

Leaf-tip Insert

Small, replaceable pads of plastic, rubber, or composition placed between spring leaves near their ends to promote slippage between the leaves during flexing.

Leak Detector

1. A device using visual or audible signals to indicate a leak. 2. A dye-type fluid that may be injected into a system that will indicate the presence of a leak.

Leak Find

A trade name for a dye solution that can be injected into a system to find difficult leaks.

Leakage Current

A small amount of current that flows through insulation when a voltage is present and heats the insulation due to it's resistance, resulting in a slight power loss.

Leakdown Test

A test using 100 psi (589.5 kPa) air pressure injected in each cylinder via the spark-plug hole or injector port to determine the leakage past the rings, gaskets, or valves.

Leaker

1. A vehicle not well prepared. 2. A vehicle leaking oil or coolant.

Lean

A term often used for lean mixture or lean out.

Lean Burn

A Chrysler electronic engine control that appeared in the mid 1970's. It maintains precise control of the spark timing to allow a very lean mixture to burn properly, reducing emissions using an analog computer.

Lean Misfire

A condition caused by a vacuum leak or open EGR valve that results in combustion, causing one or more cylinders to pass unburned fuel into the exhaust system, resulting in an increase in hydrocarbon (HC) emissions.