7.9

Question 1

What are pipes and hoses dimensions determined by?

Answer 1

External diameter and wall thickness.

Question 2

What pressures are high pressure lines?

Answer 2

Over 1500 psi (105 bar)

Question 3

What pressure are medium pressure lines?

Answer 3

Under 1500 psi

Question 4

What are low pressure lines?

Answer 4

Suction and return lines.

Question 5

What are medium and low pressure lines preferably made of?

Answer 5

Aluminium for weight saving.

Question 6

Where must steel lines be used?

Answer 6

Engine areas, areas in danger of fire and undercarriage where stones can hit.

Question 7

What can titanium lines be used for?

Answer 7

Flexible metal pipes instead of hoses.

Question 8

How are pipes and hoses proof tested?

Answer 8

With 1 1/2 it’s working pressure of compressed air and capping one end.

Question 9

What are the 2 most common support clamps for pipes?

Answer 9

Rubber cushioned and plain.

Question 10

What support clamps are used for pipes in areas subject to contamination?

Answer 10

Cushioned clamps utilising Teflon.

Question 11

What is a bonded clamp used for on pipes?

Answer 11

Secure metal, fuel, oil or hydraulic lines.

Question 12

What principle achieve the seal for flareless tube fittings?

Answer 12

Ball bush principle.

Question 13

What are the 2 flareless fittings?

Answer 13

MS and Harrison.

Question 14

How is a Harrison fitting secured?

Answer 14

Swaged in the sleeve from the inside.

Question 15

What are the 2 types of flare?

Answer 15

Single and double flare.

Question 16

What advantage do flared fittings have in engine areas?

Answer 16

They are vibration-resistant.

Question 17

What is the standard flare angle?

Answer 17

37 degrees.

Question 18

How are single flares formed?

Answer 18

Impact type or roll type.

Question 19

What colour are flared AN fittings?

Answer 19

Black are blue.

Question 20

What colour are AC flared fittings?

Answer 20

Grey or yellow.

Question 21

What angle are AC flare fittings?

Answer 21

35 degrees.

Question 22

Are AN fittings coarser or finer than AC fittings?

Answer 22

Coarser.

Question 23

What size aluminium tubing can be double flared?

Answer 23

Outside diameter 3/8 in or smaller.

Question 24

What is a disadvantage of a permaswage fitting?

Answer 24

It cannot be separated. Problematic on disassembly.

Question 25

On pipes and hoses, what is the maximum damage for sharp bottomed surface defects?

Answer 25

5%

Question 26

On pipes and hoses, what is the maximum damage for round bottomed surface defects?

Answer 26

10%

Question 27

What can the length must not be more than for a trace of impact damage on pipes and hoses?

Answer 27

5mm

Question 28

How much slack must there be on hoses between fittings?

Answer 28

5-8%

Question 29

By how much do hoses reduce in length when under pressure and expand?

Answer 29

2-4%

Question 30

Why are twisted hoses bad?

Answer 30

Shortened life and end fittings can loosen off.

Question 31

What are flexible hoses for?

Answer 31

Connect stationary moving parts and in areas of high vibration.

Question 32

What pressure are high pressure hoses?

Answer 32

3000+ psi

Question 33

What pressure are medium pressure hoses?

Answer 33

Up to 3000 psi

Question 34

What pressure are low pressure hoses?

Answer 34

Up to 600 psi

Question 35

What is psi?

Answer 35

Pounds per square inch.

Question 36

What colour are lay lines on hoses?

Answer 36

Red, yellow or white stripes.

Question 37

Other than containing hose information, what can they indicate?

Answer 37

If a hose is twisted.

Question 38

Can you re-use hose end fittings?

Answer 38

Yes, must be thoroughly inspected.

Question 39

How often must a hose be supported?

Answer 39

At least every 24 inches.

Question 40

What protective sleeves can be used on hoses?

Answer 40

Heat shrink, nylon spiral wrap, Teflon.

Question 41

What acts as a witness mark when a hydraulic fittings has been torqued?

Answer 41

A red paint mark 2-4mm wide.