- S -

Secondary Circuit

1. The electrical circuit on the output side of an ignition coil. 2. That portion of a welding machine that conducts the secondary current between the welding transformer terminals and the electrodes, or electrode and work piece. 3. The secondary passage in a carburetor.

Secondary Lock

A component of a fifth wheel locking mechanism that can be included as a backup system for the primary locks. The secondary lock is not required for the fifth wheel to function and can be either manually or automatically applied. On some designs, the engagement of the secondary lock can only be accomplished if the primary lock is properly engaged.

Secondary Pickup

An accessory that can be clamped on the high-voltage coil wire used to measure secondary ignition patterns.

Secondary Shoe

The brake shoe located toward the rear of the vehicle, in a dual-servo drum brake, having a longer and thicker lining, and providing most of the braking force during forward stops.

Secondary Winding

The winding of the ignition coil which supplies the high-tension current to the spark plug.

Section Height

The straight-distance measurement of a tire from the rim to the tread.

Section Modulus

A measure of the strength of the vehicle frame side rails.

Section Repair

A body repair that is accomplished using a section of another identical vehicle.

Section Width

The straight distance from one sidewall of a tire to the other sidewall.

Sectioned

A vehicle body that has been lowered by removing a horizontal section of metal all the way around the vehicle.

Sector

A component that is not a complete circle, such as the gear on the pitman shaft of many steering systems.

Sector Gear

A gear that converts the rotary motion of the worm in a recirculating ball or worm and sector steering gear to the straight line motion of the pitman arm.

Sector Shaft

A shaft on which the sector gear is mounted.

Sedan

A two- or four-door vehicle with front and back seats that can accommodate four to six persons.

Sedan De Ville

A sedan with an open cockpit and enclosed passenger compartment, intended to be chauffeur driven.

Sediment Chamber

A space below the cell plates of some batteries to permit the accumulation of sediment deposits flaking from the battery plates.

SEFI

Sequential electronic fuel injection.

Segments

1. A portion of a larger figure cut off by one or more lines of a plane. 2. The copper (Cu) bars of a commutator.

Seize

Two moving parts that suddenly bind together, usually due to lack of lubricant. Also known as freeze-up.

Seizing

The stiffening or "freezing" of a chain joint or shaft as a result of roughness and high friction caused by galling or lack of lubrication.