Red Seal Exam Questions with Correct Answers Solved 100% Latest Update 2025-2026
What does channel mean? - Answers It equals the number of modulators.
What is comfortable temperature and humidity? - Answers 21 to 25 Celsius. 40 to 45%
What would cause air to enter the cooling system header tank? - Answers A water valve at the sleeper.
Why would some electronic have a fuse on the positive and negative side? - Answers To protect the
circuit if someone has the disconnects off.
If there are beach marks leading to the final fracture what kind of beach marks are they? - Answers
Fatigue.
What is the procedure for installing a accessory box? - Answers Long bolts to align to push in, Timing
marks on gear shaft, Under-size countershaft bearings for ease of assembly, timing marks on
transmission input gear, lock it into a gear so that you can push it in.
Brake pot service chamber leak will show up where? - Answers You would leak right at the front at the
diaphragm.
Brake pot spring side leak will show up where? - Answers At the exhaust valve in the relay.
When you service hydraulic lining what precaution must be done? - Answers Chalk wheels.
When you service air suspension what precaution must be done? - Answers Chalk wheels.
What causes cab misalignment? - Answers Transverse torque arm.
Landing gear nut is stripped is from? - Answers An overload.
Hood chaffing on cab? - Answers Raise hood mounts.
Before servicing a closed loop hydraulic system, after de-energizing all of the components what is the
next step? - Answers Relieve reservoir pressure.
Signal range on a three wire sensor is? - Answers 0.5 to 4.5 volts. And reference voltage is 5 volts.
- Answers Change cab/no
One wheel won't lock up on primary drive? - Answers Broken axle on rear.
In a air system the purge valve won't operate? - Answers Change the governor.
In a hydraulic pump if oil bubbles in it? - Answers Cracked inlet or outlet.
What is the tool you would use for frame alignment? - Answers Plumb bob.
, If all angles are good except toe out on turn what are the possible causes? - Answers Lower steering arm
wrong, broken or bent.
Truck turns once over the weekend and turns once and locks up? - Answers Coolant in the combustion
chamber.
Weak exhaust brake would be? - Answers The actuator.
J1939 checking for resistance? - Answers Look for 60 ohms. If it shows 120 ohms we would have an
open.
Bad communication between an engine ECU and ABS? - Answers Faulty wiring harness.
What puts a bow in a gravel truck frame? - Answers Overloading or moving with loaded box up.
How many pivots are on the ram that lifts the gravel truck box? - Answers Two. Top and bottom.
What causes hard steering a slow speeds? - Answers Dry fifth wheel.
Working on air suspension on flat ground? - Answers Caulk the wheels then let the air out.
- Answers Injector malfunction.
When setting your valve the nut on tappet flush with screw? - Answers Worn cam.
Auto transmission in neutral creeps ahead? - Answers Dragging forward clutch.
Clutch disks are blue? - Answers Replace clutch. Resurface flywheel.
Where is the seat belt attached? - Answers Floor and Seat.
What is the function of the DPF switch? - Answers Passive in the middle and Off in the bottom. Forced
upward. Always returns to passive.
How many pounds in a ton? - Answers 2000 pounds.
How do you calculate the pressure of a piston? - Answers PSI equals Force divided by Area.
Full flow hydraulic filter, hydraulic work is slow? - Answers Filter plugged.
If you are drilling in a frame? - Answers Drill in the web of a frame.
Compensating valve in the master cylinder? - Answers Slows the brake release. And temperature
change.
What would happen if we had a leaking primary cup in the master cylinder? - Answers Your foot would
slowly go to the floor.
Air suspension one side high and one side low? - Answers Height control valve if there was two.
What does channel mean? - Answers It equals the number of modulators.
What is comfortable temperature and humidity? - Answers 21 to 25 Celsius. 40 to 45%
What would cause air to enter the cooling system header tank? - Answers A water valve at the sleeper.
Why would some electronic have a fuse on the positive and negative side? - Answers To protect the
circuit if someone has the disconnects off.
If there are beach marks leading to the final fracture what kind of beach marks are they? - Answers
Fatigue.
What is the procedure for installing a accessory box? - Answers Long bolts to align to push in, Timing
marks on gear shaft, Under-size countershaft bearings for ease of assembly, timing marks on
transmission input gear, lock it into a gear so that you can push it in.
Brake pot service chamber leak will show up where? - Answers You would leak right at the front at the
diaphragm.
Brake pot spring side leak will show up where? - Answers At the exhaust valve in the relay.
When you service hydraulic lining what precaution must be done? - Answers Chalk wheels.
When you service air suspension what precaution must be done? - Answers Chalk wheels.
What causes cab misalignment? - Answers Transverse torque arm.
Landing gear nut is stripped is from? - Answers An overload.
Hood chaffing on cab? - Answers Raise hood mounts.
Before servicing a closed loop hydraulic system, after de-energizing all of the components what is the
next step? - Answers Relieve reservoir pressure.
Signal range on a three wire sensor is? - Answers 0.5 to 4.5 volts. And reference voltage is 5 volts.
- Answers Change cab/no
One wheel won't lock up on primary drive? - Answers Broken axle on rear.
In a air system the purge valve won't operate? - Answers Change the governor.
In a hydraulic pump if oil bubbles in it? - Answers Cracked inlet or outlet.
What is the tool you would use for frame alignment? - Answers Plumb bob.
, If all angles are good except toe out on turn what are the possible causes? - Answers Lower steering arm
wrong, broken or bent.
Truck turns once over the weekend and turns once and locks up? - Answers Coolant in the combustion
chamber.
Weak exhaust brake would be? - Answers The actuator.
J1939 checking for resistance? - Answers Look for 60 ohms. If it shows 120 ohms we would have an
open.
Bad communication between an engine ECU and ABS? - Answers Faulty wiring harness.
What puts a bow in a gravel truck frame? - Answers Overloading or moving with loaded box up.
How many pivots are on the ram that lifts the gravel truck box? - Answers Two. Top and bottom.
What causes hard steering a slow speeds? - Answers Dry fifth wheel.
Working on air suspension on flat ground? - Answers Caulk the wheels then let the air out.
- Answers Injector malfunction.
When setting your valve the nut on tappet flush with screw? - Answers Worn cam.
Auto transmission in neutral creeps ahead? - Answers Dragging forward clutch.
Clutch disks are blue? - Answers Replace clutch. Resurface flywheel.
Where is the seat belt attached? - Answers Floor and Seat.
What is the function of the DPF switch? - Answers Passive in the middle and Off in the bottom. Forced
upward. Always returns to passive.
How many pounds in a ton? - Answers 2000 pounds.
How do you calculate the pressure of a piston? - Answers PSI equals Force divided by Area.
Full flow hydraulic filter, hydraulic work is slow? - Answers Filter plugged.
If you are drilling in a frame? - Answers Drill in the web of a frame.
Compensating valve in the master cylinder? - Answers Slows the brake release. And temperature
change.
What would happen if we had a leaking primary cup in the master cylinder? - Answers Your foot would
slowly go to the floor.
Air suspension one side high and one side low? - Answers Height control valve if there was two.
