Combination #1
Combination Vehicles Practice Test | Texas 2024 #1 Page 2 of 3
Train for FREE online with our Texas CDL combination vehicle test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a TX combination license in 2024, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that DMV requirements for issuing a combination license may vary from state to state.
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8 . Air pressure in the ____ air line is controlled by either the foot brake or trailer hand brake.
Auxiliary
Air pressure in the service air line is controlled by either the foot brake or trailer hand brake. The service air line is also known as the control line or signal line. This line is connected to relay valves, which allow the trailer brakes to be applied more quickly than would otherwise be possible.
9 . If a trailer's spring brakes do not release when you push the tractor air supply control, you should:
Drive normally without checking anything.
It is important that all of your vehicle's equipment is in proper working condition before you begin a trip. If a trailer's spring brakes do not release when you push in the tractor air supply control, you should make sure the air line connections are properly attached and sealed.
10 . If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can:
Assume the vehicle has ABS.
If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can check under the trailer for wheel speed sensors coming from the back of the brakes.
11 . To test the trailer service brakes, you should:
Move the vehicle forward slowly and apply the brakes with the hand control.
To test the trailer service brakes, you should first ensure that the braking system has a normal air pressure level, then release the parking brake. You should then move the vehicle forward slowly and apply the brakes with the hand control. If the trailer service brakes are working properly, you will feel the brakes activate.
12 . If oil and water build up in your vehicle's air tanks, the brakes:
Will be extremely sensitive.
Air tanks should be drained daily to remove water and oil buildup. An excess of oil and water in the air tanks can interfere with proper brake function.
13 . To help prevent rollovers, you should:
Keep the load on one side of the trailer.
To lower the risk of a rollover, load your cargo as closely to the ground as possible. To further reduce this risk, take curves and corners slowly.
14 . A lightly-loaded combination vehicle will stop more slowly than a fully-loaded vehicle because:
The suspension springs only operate when a trailer reaches a minimum weight.
