Used car guide

2017 Mercedes-Benz B-Class: common problems and what to check

What gets flagged at MOT on 2017 Mercedes-Benz B-Classs, from 5,689 tests in 2025, plus known faults and what to look at before you buy one.

5,689MOT tests in 2025
80%pass first time (all 2017 cars: 78%)
6,300typical miles a year
2×the usual rate for number plate lights

What stands out

Parts flagged at MOT more often on 2017 Mercedes-Benz B-Classs than on all cars registered in 2017.

  • Number plate lights2× usual
    Mercedes-Benz B-Class
    4.8% All 2017 cars
    2.4%

    Failed outright at MOT: 3.1%, against 0.7% of all 2017 cars. The rest were advisories or minor defects.

    Rough price £5–£40 our estimate

    At the viewing: Check the number plate lights work and the plates are clean and legal.

  • Link ball joint covers4.8× usual
    Mercedes-Benz B-Class
    2.4% All 2017 cars
    0.5%

    Failed outright at MOT: 1.1%, against 0.3% of all 2017 cars. The rest were advisories or minor defects.

    Rough price £60–£150 (one joint) ClickMechanic

    At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

By area

The share of 2017 Mercedes-Benz B-Class MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Tyres
    29% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Brakes
    19% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Suspension
    10% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Lights and electrics
    9% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Wipers, windscreen and mirrors
    6% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

  • Seats and seatbelts
    3% of testsRough price £80–£250

    At the viewing: Pull each seatbelt sharply. It should lock, and retract cleanly.

Looking at a Mercedes-Benz B-Class?

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Other years

YearMOT testsMost flagged
2019599Tyres 25%
20183,892Tyres 31%
20165,353Tyres 31%
20155,654Tyres 32%
20148,185Tyres 32%
20136,957Tyres 33%
20125,658Tyres 32%
20113,373Brakes 42%
20104,279Brakes 44%
20093,989Brakes 48%
20083,072Brakes 51%
20072,249Brakes 47%
20061,611Brakes 51%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2017 Mercedes-Benz B-Classs registered in 2017. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score