Hydrualic 5 Tonne Jack

Question 1

Hydraulic jacks have what type of ram to provide high lift?

Answer 1

Telescopic

Question 2

What are the 3 advantages of a hydraulic jack?

Answer 2

Load is raised with minimum effort- through a lever

The load is under control at all times- achieved by the suction/delivery valve

No danger of hack retracting under load, achieved by the release valve and mechanical locks

Question 3

What are the 3 main assemblies of a hydraulic jack

Answer 3

Hydraulic body
Trestle type
Towbar assembly

Question 4

What type of component is common to all jacks?

Answer 4

Hydraulic body

Question 5

The hydraulic body consists of what components?

Answer 5

Reservoir

Pump assembly

Hydraulic cylinder

Question 6

What component makes sure the jack is perpendicular

Answer 6

Spirit level

Question 7

What type of fluid does the reservoir of jack have?

Answer 7

OM 18

Question 8

The base of the reservoir is fitted with what?

Answer 8

Drain screw and the top is fitted with a bush which has the dipstick and air valve

Question 9

Why is the thread partially relived on the bush?

Answer 9

To provide an air path between the reservoir and atmosphere

Question 10

What does the air valve prevent?

Answer 10

Formation of a vacuum when raising or pressure when lowering in the reservoir

Also prevent dirt ingress when it is out of use

Question 11

What is the mechanical actuator used to give?

Answer 11

Unidirectional force in a unidirectional motion

Question 12

The rod gland prevents what?

Answer 12

Pressurised oil from leaking past the interface between the rod and the head

This area is called the rod gland

Question 13

The rod wiper prevents what?

Answer 13

Contaminants from entering the cylinder when extended and retracted

Question 14

Why must the safety locking nut be fully wound down when the ram is fully extended?

Answer 14

The ram needs to be raised to release them

Question 15

What type of seals are fitted to the pump?

Answer 15

Seals , o ring seals and sealing washers

Question 16

How is the plunger raised and lowered?

Answer 16

By the pump handle through a fulcrum - adjusted by the rotating spigot

Question 17

What does closing the relief valve do?

Answer 17

Isolates the hydraulic cylinder from the reservoir enabling it to be pressurised?

Question 18

What does unscrewing the release valve do?

Answer 18

Allows pressurised fluid in the cylinder to return to the reservoir

Question 19

The jack is protected from excess pressure by what?

Answer 19

Pre set overload valve that must not be adjusted

This also limits the load lifting capacity

Question 20

What is the weight overload valve set to?

Answer 20

5.3-5.7 tonnes

Question 21

What is the purpose of the overload valve

Answer 21

To protect components and personnel

Do not adjust screw

Question 22

What are the 5 things you should do when storing the jack?

Answer 22

Open the air valve one revolution

Fully extend both rams and lightly lubricate

Retract rams

Close air valves

Close release valve

Question 23

What will unscrewing the release valve do when lowering the jack?

Answer 23

Uncontrolled decent

Question 24

What is the standard serviceability test?

Answer 24

Check rams raise to full extent

Check rams fully retract

Question 25

How do you bleed a jack?

Answer 25

Open release valve and air valve

Pump vigorously