T4 ASE Brakes 2026 Exam
Questions and Correct
Answers | New Update
Psi loss rate for Straight Truck - ANSWER ✔✔2 psi/minute
Psi loss rate for combination vehicle - ANSWER ✔✔less than 3
psi/minute
Service Brake Pressure Drop Test - ANSWER ✔✔Apply service
brake to 90 psi. Loss rate should be less than 3 psi/minute for straight
vehicles and less than 4 psi/minute for combination vehicles.
Improperly adjusted brake shoes - ANSWER ✔✔Cause
,1) brake imbalance
2) increased stopping distance
3) excessive heat and wear
Instability and premature wear - ANSWER ✔✔a 4 psi difference in
the air delivery between axles is enough to cause instability and
premature wear.
Troubleshooting poor brake performance due to air - ANSWER ✔✔1)
inspect air compressor
2) verify pressure build up
3) look for clogged air compressor filter
4) possible slipping belt
5) possible air leaks
6) possible defective governor
Pressure Governors - ANSWER ✔✔1) regulates air going to system
2) adjustable pressure
3) defective governor or out of adjustment can cause compressor to
function improperly.
, 4) designed to regulate the compressors output.
5) may be attached to compressor or externally mounted.
Air Compressors - ANSWER ✔✔1) Power is transferred to the air
compressor by either an internal gear or by an external belt. Belt is most
common.
2)air can be drawn directly from the atmosphere through a filter.
3) Pistons push the air through a discharge valve to the supply reservoir.
Supply Reservoir "Wet Tank" - ANSWER ✔✔1) tank closest to the
compressor.
2) "pop off valve" located on this tank to keep from over pressuring the
system.
Pop-off valve - ANSWER ✔✔Also known as the pressure relief
valve, exhaust valve, adjustable pressure limiting (APL) valve, or
overflow valve; this valve is the point of exit of excessive pressure
buildup before damaging air components.
Manual and Automatic Drain Valves - ANSWER ✔✔1) installed in
each reservoir/tank to help purge the system from moisture.
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
Questions and Correct
Answers | New Update
Psi loss rate for Straight Truck - ANSWER ✔✔2 psi/minute
Psi loss rate for combination vehicle - ANSWER ✔✔less than 3
psi/minute
Service Brake Pressure Drop Test - ANSWER ✔✔Apply service
brake to 90 psi. Loss rate should be less than 3 psi/minute for straight
vehicles and less than 4 psi/minute for combination vehicles.
Improperly adjusted brake shoes - ANSWER ✔✔Cause
,1) brake imbalance
2) increased stopping distance
3) excessive heat and wear
Instability and premature wear - ANSWER ✔✔a 4 psi difference in
the air delivery between axles is enough to cause instability and
premature wear.
Troubleshooting poor brake performance due to air - ANSWER ✔✔1)
inspect air compressor
2) verify pressure build up
3) look for clogged air compressor filter
4) possible slipping belt
5) possible air leaks
6) possible defective governor
Pressure Governors - ANSWER ✔✔1) regulates air going to system
2) adjustable pressure
3) defective governor or out of adjustment can cause compressor to
function improperly.
, 4) designed to regulate the compressors output.
5) may be attached to compressor or externally mounted.
Air Compressors - ANSWER ✔✔1) Power is transferred to the air
compressor by either an internal gear or by an external belt. Belt is most
common.
2)air can be drawn directly from the atmosphere through a filter.
3) Pistons push the air through a discharge valve to the supply reservoir.
Supply Reservoir "Wet Tank" - ANSWER ✔✔1) tank closest to the
compressor.
2) "pop off valve" located on this tank to keep from over pressuring the
system.
Pop-off valve - ANSWER ✔✔Also known as the pressure relief
valve, exhaust valve, adjustable pressure limiting (APL) valve, or
overflow valve; this valve is the point of exit of excessive pressure
buildup before damaging air components.
Manual and Automatic Drain Valves - ANSWER ✔✔1) installed in
each reservoir/tank to help purge the system from moisture.
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
