Michigan SOS mechanic test

Heavy-Duty Suspension & Steering

Heavy-Duty Suspension & Steering is one of the 20 Secretary of State mechanic certification tests. Here's what the test covers, according to the state's published outline.

Topic guide · questions soon

What's on the test

Official topic	Weight
Steering system diagnosis Power steering analyzer tool Power steering unit noise Power steering leak System bleeding Aerated power steering fluid Free play in steering Wheel shimmy Tie rod end play	19%
Suspension diagnosis Air ride suspension operation Leaf springs Hendrickson suspensions Torque rods Tandem axle alignment Tracking rods	19%
Wheel alignment Toe-in adjustment Tire inflation Tire wear analysis Camber / caster / toe Effects of different angles on vehicle operation	19%
Basic steering system knowledge Front suspension components Steering gear operation / diagnosis Wheel bearings Steering wheel free play Steering knuckle wear Power steering pump replacement	19%
Basic suspension knowledge Castle nut tightening Lug nut tightening sequence Walking beam suspension Suspension adjustment Equalizing beam suspensions Adjustable trailer axles	19%
Fifth wheel knowledge Fifth wheel adjustment Fifth wheel diagnosis Hardware grade	6%

Weights are shown exactly as published by the SOS (they total 101%).

Source: SOS Mechanic Testing Categories Overview (PDF). Test format: most SOS mechanic tests have 55 questions, and a few have 65–100 (SOS FAQ). Passing scores vary by test; your result letter shows the passing score and your score.

Practice questions coming soon

The Heavy-Duty Suspension & Steering practice bank is being written to the official outline below. The All-Mechanic pass will include it when it launches.

Banks available now: Engine Repair · Front End, Suspension & Steering · Brakes & Braking Systems · Electrical Systems · Engine Tune-Up & Performance

Test-day facts

Taken on a touch-screen kiosk at any Secretary of State office. Schedule through SOS e-Services.
$18 per test (effective July 1, 2026).
“Quick pass”: the test ends once you reach the minimum passing score.
No reference materials or electronic devices are allowed.
If you don't pass, your result letter breaks down your performance by subcategory.

Source: michigan.gov/sos mechanic testing

Heavy-Duty Suspension & Steering test FAQ

How many questions are on the Michigan Heavy-Duty Suspension & Steering test?

The Secretary of State says most mechanic tests have 55 questions and a few have 65 to 100. The test is “quick pass,” so it ends as soon as you reach the minimum passing score.

What topics are on the Heavy-Duty Suspension & Steering test?

The SOS Mechanic Testing Categories Overview lists: Steering system diagnosis (19%), Suspension diagnosis (19%), Wheel alignment (19%), Basic steering system knowledge (19%), Basic suspension knowledge (19%), Fifth wheel knowledge (6%).

How much does the test cost, and where do I take it?

Each mechanic test costs $18 (effective July 1, 2026). Tests are taken on a touch-screen kiosk at any Secretary of State office; pre-register and schedule through SOS Online Services. Approved automotive schools can also test their students.

Are these the real test questions?

No. MI Trade Prep questions are original practice items written to the official topic outline. They are not actual exam questions, and MI Trade Prep is not affiliated with the Michigan Department of State.

Sources: SOS mechanic testing · SOS mechanics page · SOS mechanic FAQ