The 2018 Mercedes-Benz GLS-Class has 21 owner complaints with NHTSA across 2 component categories. Use this checklist before you put money down — every item below is grounded in the actual failure pattern on this vehicle, not generic advice.
1
Inspect the brakes
What to look for: Pulsing brake pedal, pulling to one side when braking, squealing or grinding, soft pedal that goes to the floor. (5 owner complaints on this vehicle
· typical repair $450 · failures cluster ~4,500 mi)
On the test drive: Hard brake from 40 mph in a safe spot — pedal should be firm, stop should be straight. A pulse means warped rotors ($300–$600).
What to look for: Bouncing after bumps, knocking over potholes, sagging on one corner, harsh ride with all the dampening gone. (3 owner complaints on this vehicle
· typical repair $900 · failures cluster ~8,000 mi)
On the test drive: Drive over a series of bumps or a railroad crossing — clunks point to worn end links, ball joints, or strut mounts.
The seller's transparency on these tells you what kind of seller you're dealing with.
Inspection items derived from 21 owner complaints and 0 active recall campaigns filed
with NHTSA on the 2018 Mercedes-Benz GLS-Class. Category-specific guidance is written by ProblemsByVin contributors with ASE-certified mechanic
review. This checklist is meant to surface known patterns — it doesn't replace a paid pre-purchase inspection by a
qualified shop, which we recommend for any used vehicle priced over a few thousand dollars.