Model Reports 8 min read Updated 13 Jul 2026

Mercedes-Benz B-Class 2008: reliability & common MOT faults

On the 2008 Mercedes-Benz B-Class, MOT failures for Service brake performance and Drive shafts — Joints (front) show up more often than on similar cars of the same age and mileage. Figures come from UK DVSA open data for tests in 2025 (1,326 failed first-attempt tests). Figures are among first-attempt failed MOT tests, not among all tests.

Sample

1,326 failed first-attempt tests · 2,936 first tests (test year 2025)

Standout pattern

Service brake performance — about 5.4× more often than on similar cars.

What to check

  • Service brake performance — about 5.4× more often than similar cars
  • Drive shafts — Joints (front) — about 3.5× more often than similar cars
  • Rigid brake pipes (rear) — about 3.2× more often than similar cars

Common faults

Failure patterns that show up more often on this registration year than on similar cars.

These MOT failure patterns show up more often on this registration year than on similar cars of the same class, age, and mileage.

Based on 1,326 failed first-attempt tests in 2025.

Service brake performance

This failure pattern appears about 5.4× more often than on similar cars — recorded on 42 failed first-attempt tests; 3.2% of failed tests for this model year.

Any 42 failures ×5.4 3.2% of failed first tests Likely

Drive shafts — Joints (front)

This failure pattern appears about 3.5× more often than on similar cars — recorded on 299 failed first-attempt tests; 22.5% of failed tests for this model year.

Front 299 failures ×3.5 22.5% of failed first tests Likely

No patterns met the strongest callout thresholds on this page; showing the highest-lift rows that still cleared the display floors.

# Fault pattern Location Failures vs similar cars Share of fails Confidence
1 Service brake performance
Brakes > Brake performance > Service Brake Efficiency (sp) > Rbt (sp) > Service brake performance
 Any 42 ×5.4 3.2% Likely
2 Drive shafts — Joints (front)
Body, chassis, structure > Transmission > Drive shafts > Joints
 Front 299 ×3.5 22.5% Likely
3 Rigid brake pipes (rear)
Brakes > Rigid brake pipes
 Rear 103 ×3.2 7.8% Likely
4 Shock absorbers (front)
Suspension > Shock absorbers
 Front 92 ×3.0 6.9% Likely
5 Parking brake control — Lever
Brakes > Parking brake control > Lever
 Any 32 ×2.6 2.4% Possible
6 Coil spring (rear)
Suspension > Springs > Coil springs > Coil spring
 Rear 124 ×2.5 9.4% Possible
7 Ball joint (front)
Suspension > Suspension arms > Ball joint
 Front 193 ×2.5 14.6% Possible
8 Visibility — Washers (front)
Visibility > Washers
 Front 80 ×2.0 6.0% Possible

Only patterns that clear minimum sample and elevation thresholds are shown (at least 20 failures and about 2.0× more often than similar cars).

Note: Rates and comparisons are among first-attempt failed tests, not all MOTs. Patterns come from MOT defect codes — not manufacturer service bulletins, recalls, or a diagnosis of any individual car. Failures and advisories are listed separately.

Advisories

Notes recorded at the test that appear more often than on similar cars.

Advisory notes recorded on failed first-attempt tests that appear more often than on similar cars.

# Advisory pattern Location Notes vs similar cars Share Confidence
1 Seat belts — Condition (rear)
Seat belts and supplementary restraint systems > Seat belts > Condition
 Rear 44 ×7.0 3.3% Elevated
2 Anti-roll bar (rear)
Suspension > Anti-roll bars > Anti-roll bar
 Rear 22 ×3.6 1.7% Elevated
3 Rigid brake pipes (front)
Brakes > Rigid brake pipes
 Front 125 ×2.8 9.4% Elevated
4 Rigid brake pipes (rear)
Brakes > Rigid brake pipes
 Rear 226 ×2.7 17.0% Likely
5 Flexible brake hoses (front)
Brakes > Flexible brake hoses
 Front 63 ×2.6 4.8% Elevated
6 Individual direction indicators (rear)
Lamps, reflectors and electrical equipment > Direction indicators > Flashing type > Individual direction indicators
 Rear 46 ×2.3 3.5% Elevated
7 Non-component advisories (rear)
Non-component advisories
 Rear 108 ×2.1 8.1% Elevated
8 Shock absorbers (front)
Suspension > Shock absorbers
 Front 102 ×2.1 7.7% Likely
Note: Advisories are not a fail rate — they flag issues noted at the test, often before they become failures.

FAQs

Short answers about how to read this model-year guide.

We do not show a single reliability score for the 2008 Mercedes-Benz B-Class on this page. Among 1,326 failed first-attempt MOT tests (test year 2025), Service brake performance appears more often than on similar cars (about 5.4× more often than similar cars; 42 observed failures; 3.2% of failed tests). Treat this as a pre-purchase checklist from DVSA open data — not a guarantee for any individual car.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Service brake performance (about 5.4× more often than similar cars; 42 observed failures; 3.2% of failed tests). These are statistical signals, not a diagnosis of any individual car.
Service brake performance shows up more often than on similar cars (about 5.4× more often than similar cars; 42 observed failures; 3.2% of failed tests). That does not prove a design fault — age, mileage, and how the car was used still matter. Treat it as a pre-purchase check point, not a manufacturer service bulletin.
Common MOT problem areas for the 2008 Mercedes-Benz B-Class include Service brake performance, Drive shafts — Joints (front), Rigid brake pipes (rear). These patterns show up more often than on similar cars after we filter out sparse noise — not a full list of every possible fault on an individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2008 Mercedes-Benz B-Class (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics — not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.
PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars — not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics — this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces — but does not remove — differences in how cars were used and maintained.
  • We never invent pass rates, star scores, or ranks when those data marts are missing.

Contains public sector information licensed under the Open Government Licence v3.0.

Most reliable Mercedes-Benz models

See brand-wide MOT rankings and year guidance for Mercedes-Benz (separate from this model-year report).