Kenworth T410, Driver'S Handbook Manual

Page: 218 / 418

Page 192 CAT: 8612 November 2019
OPERATING INSTRUCTIONS
3. Engine brakes or other auxiliary brake systems should never be
used simultaneously with the foot brake. To do so unbalances
the brakes and can cause the drive wheels to skid, resulting in a
jackknife.
Operating the engine brakes when the semi is unladen during wet
weather should be prohibited because, in an emergency, the driver
will instinctively apply the service brakes and possibly skid the drive
wheels, which can cause a jackknife.
4. Brakes should be balanced, i.e. brake force generated must be
in direct proportion to the load carried on the axle being braked.
For this to occur:
• Brakes should be same type and size.
• Linings should all be the same material.
• Pipe lengths, sizes and connections should be appropriate to
allow all brakes to apply as near as possible to simultaneously.
5. Semi-trailer suspension roll stiffness should be equal to, or
greater than, that of the truck to minimise degradation of
brake balance by minimising side-to-side weight transfer when
cornering.
6. Semi-tankers should never be operated with less load on each
individual drive axle than on each individual semi-tanker axle, i.e.
if the semi-tanker combination is to be driven with some tanks
empty, the middle compartment should be emptied first, then the
rear and lastly the compartment over the drive axles.
The combination should not be operated with the compartment over the
drive axles empty and other compartments full.
Typically, an unladen semi-tanker or tipper will skid on wet roads and
possibly jackknife at 10% to 15% of normal brake pedal movement. Drivers
must be aware of this and must drive at least 2 or 3 times the normal
distance behind the vehicle in front under these conditions.