Common Mercedes B-class Problems, Faults, and Repair Costs
Every known Mercedes B-class MOT issue, ranked by how common it is and what it costs to fix. Based on 117,828 real MOT tests across 15 model years.
Segment: small family car | Fuel: Diesel, Petrol, Electric
81%
Mercedes B-class pass rate
87%
Mercedes average
82%
National average
The Mercedes B-class has an average MOT pass rate of 81%, which is 6 points below the Mercedes average and 1 points below the national average. Newer MERCEDES B-CLASSs show better MOT pass rates than older ones, with an average improvement of 14 percentage points.
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Enter your reg plate to see the specific issues found on your car, plus a health score and running cost estimate.
Most Common Mercedes B-class MOT Issues
Ranked by how likely they are to affect your Mercedes B-class, with typical repair costs
Brakes
High likelihood£80 - £450
Typical repair cost
Common advisories:
Brake discs worn, brake pads thin, handbrake adjustment needed
Failure points:
Brake disc excessively worn, brake pipe corroded, brake efficiency below minimum
Suspension
High likelihood£150 - £600
Typical repair cost
Common advisories:
Suspension arm bush worn, shock absorber misting, spring corroded
Failure points:
Coil spring broken, ball joint excessive play, shock absorber leaking
Lights
High likelihood£15 - £200
Typical repair cost
Common advisories:
Headlamp aim slightly out, lens deteriorated
Failure points:
Headlamp not working, brake light not functioning, indicator failure
Steering
High likelihood£100 - £500
Typical repair cost
Common advisories:
Track rod end has slight play, steering rack boot deteriorated
Failure points:
Steering rack leaking, track rod ball joint worn beyond limits
Body & Structure
High likelihood£200 - £1200
Typical repair cost
Common advisories:
Surface corrosion on subframe, slight body panel damage
Failure points:
Structural corrosion, body mounting corroded through, chassis weakness
Tyres
Moderate likelihood£50 - £300
Typical repair cost
Common advisories:
Tyre approaching legal limit, slight damage to sidewall
Failure points:
Tyre below minimum tread depth, tyre has a cut exposing ply
Exhaust & Emissions
Lower likelihood£80 - £800
Typical repair cost
Common advisories:
Exhaust mounting corroded, slight exhaust leak
Failure points:
Exhaust emissions exceed limits, catalytic converter efficiency low, DPF warning
Windscreen & Wipers
Lower likelihood£10 - £350
Typical repair cost
Common advisories:
Minor windscreen chip, wiper blade deteriorated
Failure points:
Windscreen crack in swept area, wiper does not clear windscreen
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Mercedes B-class Reliability by Year
MOT pass rate for each model year, based on real test data
| Year | Fuel | Engine | Pass Rate | Fail Rate |
|---|---|---|---|---|
| 2019 | Diesel | 1.9L | 93% | 7% |
| 2018 | Petrol | 1.6L | 90% | 10% |
| 2017 | Electric | 0.0L | 88% | 11% |
| 2016 | Electric | 0.0L | 87% | 13% |
| 2015 | Electric | 0.0L | 86% | 14% |
| 2014 | Diesel | 1.8L | 83% | 16% |
| 2013 | Diesel | 1.8L | 82% | 18% |
| 2012 | Diesel | 1.6L | 81% | 19% |
| 2011 | Petrol | 1.7L | 73% | 26% |
| 2010 | Petrol | 1.7L | 74% | 26% |
| 2009 | Diesel | 2.0L | 74% | 26% |
| 2008 | Petrol | 1.7L | 71% | 28% |
| 2007 | Diesel | 1.7L | 72% | 27% |
| 2006 | Petrol | 2.0L | 71% | 27% |
| 2005 | Petrol | 2.0L | 73% | 27% |
Mercedes B-class Running Costs
Want to know the full annual running costs for the Mercedes B-class? Including fuel, tax, insurance, and predicted repairs based on MOT history.
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Mercedes B-class FAQ
What are the most common Mercedes B-class problems?
The most common Mercedes B-class MOT problems are brakes, suspension, lights, steering, body & structure issues. These are the areas most likely to cause advisories or failures during an MOT test, based on 117,828 real tests.
Is the Mercedes B-class reliable?
The Mercedes B-class has an average MOT pass rate of 81%, which is 1 points below the national average of 82%. This is considered good reliability.
Which year Mercedes B-class is most reliable?
The 2019 Mercedes B-class is the most reliable year with a 93% MOT pass rate. Avoid the 2006 model year if reliability is your priority, as it has the lowest pass rate at 71%.
How much does it cost to fix common Mercedes B-class faults?
Repair costs vary by issue. Brake work on a Mercedes B-class typically costs £80-£450, suspension repairs cost £150-£600, and exhaust/emissions fixes cost £80-£800. Lighting and wiper fixes are usually under £200.
Check a Specific Mercedes B-class
Enter any reg plate to see the exact MOT history, defects found, health score, and running cost estimate for that specific car.
Other Mercedes Models
Common problems pages for other Mercedes models