© 2012 delmar, cengage learning automotive plumbing: tubing and pipe chapter 24

© 2012 Delmar, Cengage Learning© 2012 Delmar, Cengage Learning

Automotive Plumbing: Tubing and Pipe

Chapter 24


Objectives• Describe the different types of tubing used on

automobiles• Understand the different types of tubing

connections• Repair damaged tubing


Introduction• Tubing and pipe

– Found on automobiles and on shop equipment

• This chapter covers:– Tubing and pipe service

– Different types of plumbing parts

– Connectors used with tubing and pipe


Tubing• Often called “line”

– No threads at its ends

– Can be made of copper, steel, or plastic• Manufacturers choose the least expensive

alternative to do the job safely

• Copper tubing – Can be soft or rigid

– Work hardens

• Plastic – Used for vacuum or oil pressure lines


Tubing (cont'd.)• Steel tubing

– Galvanized to prevent rust

– Double-walled when used for brake lines

– Armor: Steel coil around outside of a break tube

• Tube fittings– Many types of fittings join tubing to components

– Connectors are used between tubing and parts (e.g., oil pump)


Flared Connections• Used when two steel fuel lines are connected

– Flare connection is suited for high-pressure applications

– Must be used for brakes or power steering

• Two kinds of flares:– Double flare (SAE)

– Bubble flare (ISO)


Flared Connections (cont'd.)• SAE-type double flare

– Used with an inverted flare nut

• SAE flare: can be a either a single or double – Single flare: not used on small automotive tubing

• ISO flares: used since the early 1980s– Bubble is formed in the line near its end


Compression Fittings• Compression fittings: flareless fittings

– One kind uses a brass sleeve called a ferrule

• To install a compression fitting:– Slide nut onto tubing

– Slide the sleeve onto the tubing

– Insert the tubing as far into the fitting as possible

– Tighten one and a fourth turns after both fittings have contact


Compression Fittings (cont'd.)• Characteristics

– Should not be used on high-pressure applications

– Can also be used with rigid plastic tubing

– Double compression fitting: no separate sleeve but compresses front part of nut against tubing

– O-ring connections: used to seal fittings

• Unions – Join two pieces of tubing together


Pipe Fittings• Pipe threads are used for:

– Heater outlets

– Oil gallery

– Coolant drain plugs

– Oil and coolant temperature sending units

– Compresses air lines in the shop

• Fittings on copper, brass, or iron pipe – Use tapered threads


Pipe Fittings (cont'd.)• Characteristics

– Size of pipe thread • Determined by the size of the piece of pipe

– Pipe coupling• Joins two pipes

– Street elbow• Male thread on one end

– Close nipple • Tapered threads on each end that join in middle

– Long nipple • Plain pipe separates the threads


Shutoff Valves• Also called draincocks

– Often found on the bottom of a radiator

– Turning end of valve opens or closes it

– Plastic radiator tanks usually have a plastic drain valve


Tubing Service• Tubing comes in precut lengths with flare fittings• Considerations

– Do not kink bulk tubing when unrolling

– Use a tubing wrench or flare nut wrench to loosen a flare fitting

– Damaged steel fuel lines can be cut and repaired• New lines fabricated with a flaring tool


Tubing Service (cont'd.)• Cutting tubing

– Cut square on the end

– Tubing cutter is tightened against tubing then rolled around it

– Remove burrs

• Bending tubing– Too sharp of a bend will cause a kink

– Install fittings and flare both ends before bending tubing


Tubing Service (cont'd.)• Bending spring: installed over the tubing

– Prevents kinking

• Steel lines: should not have long, straight runs• Long runs: should be supported with clamps• Flaring the ends of tubing

– Double flare or an ISO flare• Double flaring is a two-step procedure

• ISO flaring– Bubble or ridge is formed in the line a short way

back from its end


Installing Tubing• When installing tubing

– Leave first fitting loose

• Union repairs– Union is used to repair a damaged line

• Better repair than hose for high-pressure lines

• Using hoses to repair tubing– When a section of steel fuel line is damaged, it is

best to replace it and its flared ends and fittings


Transmission Oil Cooler Line Repairs

• Union– Best repair for a transmission cooler line

• Kinks are often repaired with hose– If rubber hose is used: flare both ends of the

metal tubing

– Edges of a double flare can cut the rubber hose over time


Nylon Fuel Injection Tubing• Nylon line is connected to steel line

– Push connector is used

– Some nylon lines are coupled together with a “spring lock” connector

– There are two O-rings on the male coupling

– If the garter spring is damaged or missing, it can be replaced in the coupling


Pipe Service• Pipe is cut with a pipe cutter

– Resembles a large tubing cutter

• Pipe dies – Form threads on the outside of the pipe

• Thread sealer – Used between threads

• After hand tightening pipe – Tighten further a minimum of two and a half turns

© 2012 delmar, cengage learning automotive plumbing: tubing and pipe chapter 24

Documents

pipe slide

cengage learning tubing

cengage learning slide

steel tubing

copper tubing

end slide

slide nut

pieces of tubing