Auto Mechanics Paper 2,Nov/Dec 2012.  
Questions:   1 2 3 4 5   Main
General Comments

Question 3

(3) (a)       Define the term chassis frame.

     (b)       Sketch the transmission layout of a conventional motor vehicle.

     (c)       Label the following on the sketch in (b):

  1. gearbox;
  2. propeller shaft;
  3. rear axle;
  4. clutch.

(d) Explain why the chassis frame is narrowed at the front and upswept at the rear.

(e) State one merit of a rear engine, rear wheel drive vehicle.

Most of the candidates who attempted this question performed well in parts (a), (b) and (c).  However, parts (d) and (e) were poorly answered by the candidates.  The required responses to parts (d) and (e) are:

(d) The chassis – frame is narrowed at the front to provide a wider steering lock and therefore smaller turning circle while the upswept at the rear gives room for the vertical movement of rear axle as the vehicle travels over road bumps.

(e)  The merits of a rear engine, rear wheel dive are:

-  fumes and noise and behind passengers
-  there is excellent traction especially when climbing;
- there is more room for passengers: legs due to the elimination of propeller shaft tunnel;
-  there is greater weight distribution;
-  simplified steering arrangement as there is no interference due to worn transmission components;
-  lighter steering because there is less weight on the front wheels;
-  exhaust pipe and silencer is shorter.


Most of the candidates who attempted this question performed excellently well.  However, they had problems with parts (bii) and (biii).  The required responses to these parts are: 

(bii) regulator controls the rate of charge from the generator thus ensuring constant current for the electrical and electronic parts.

(biii)  the solenoid switch connects the battery, ignition switch and starter motor together thus causing the engine to start.

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