2003 Mercedes-Benz A-Class diesel: common problems and MOT failures

What goes wrong more than usual on a 2003 Mercedes-Benz A-Class diesel?

Parts flagged at MOT more often on the 2003 Mercedes-Benz A-Class diesel than on all cars registered in 2003.

• Rigid brake pipes2× usual
  Mercedes-Benz A-Class

  38.4% All 2003 cars

  18.9%

  Failed outright at MOT: 5.7%, against 3.1% of all 2003 cars. The rest were advisories or minor defects.

  Rough price £100–£400 our estimate

  At the viewing: Ask to see underneath, or check the MOT advisories: corroded brake or fuel pipes get worse every year and fail the MOT when they do.

• Shock absorbers2.5× usual
  Mercedes-Benz A-Class

  15.8% All 2003 cars

  6.4%

  Failed outright at MOT: 3.4%, against 1.6% of all 2003 cars. The rest were advisories or minor defects.

  Rough price £200–£300 (pair, average rear to front) ClickMechanic

  At the viewing: Push down hard on each corner. It should bounce once and settle. Look for oil on the shock absorber body.

• Sub-frame2.6× usual
  Mercedes-Benz A-Class

  12% All 2003 cars

  4.6%

  Failed outright at MOT: 1.9%, against 0.3% of all 2003 cars. The rest were advisories or minor defects.

  Rough price £300–£1,000 our estimate

  At the viewing: Look underneath at the frame the suspension bolts to. Flaky rust or holes are expensive to fix.

• Number plates1.9× usual
  Mercedes-Benz A-Class

  14.1% All 2003 cars

  7.4%

  Failed outright at MOT: 1.1%, against 0.8% of all 2003 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.

• Steering rack inner joints2.7× usual
  Mercedes-Benz A-Class

  9.3% All 2003 cars

  3.4%

  Failed outright at MOT: 0%, against 0% of all 2003 cars. The rest were advisories or minor defects.

  Rough price £100–£450 our estimate

  At the viewing: On a straight road the steering wheel should sit straight. Listen for knocks when turning, and check the steering feels even.

Common 2003 Mercedes-Benz A-Class diesel MOT failures and advisories

The share of 2003 Mercedes-Benz A-Class diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Brakes
  54% 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
  51% 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
  42% of testsRough price £10–£80

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

• Tyres
  28% 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.

• Steering
  14% of testsRough price £100–£450

  At the viewing: On a straight road the steering wheel should sit straight. Feel for play or knocking when turning.

• Wipers, windscreen and mirrors
  13% of testsRough price £15–£250

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

Questions to ask the seller before buying a 2003 Mercedes-Benz A-Class diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

1. Any recent work on the rigid brake pipes? (Flagged at MOT 2× as often on the 2003 Mercedes-Benz A-Class diesel as on other cars the same age.)
2. Any recent work on the shock absorbers? (Flagged at MOT 2.5× as often on the 2003 Mercedes-Benz A-Class diesel as on other cars the same age.)
3. Any recent work on the sub-frame? (Flagged at MOT 2.6× as often on the 2003 Mercedes-Benz A-Class diesel as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?