2004 Mercedes-Benz A-Class diesel: common problems and MOT failures

What goes wrong more than usual on a 2004 Mercedes-Benz A-Class diesel?

Parts flagged at MOT more often on the 2004 Mercedes-Benz A-Class diesel than on all cars registered in 2004.

• Rigid brake pipes2.2× usual
  Mercedes-Benz A-Class

  38.7% All 2004 cars

  17.4%

  Failed outright at MOT: 8.6%, against 3% of all 2004 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 absorbers2.9× usual
  Mercedes-Benz A-Class

  19.3% All 2004 cars

  6.7%

  Failed outright at MOT: 6%, against 1.7% of all 2004 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.

• Steering rack inner joints3.8× usual
  Mercedes-Benz A-Class

  13.9% All 2004 cars

  3.7%

  Failed outright at MOT: 0%, against 0% of all 2004 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.

• Flexible brake hoses2.1× usual
  Mercedes-Benz A-Class

  11.8% All 2004 cars

  5.6%

  Failed outright at MOT: 2.3%, against 1.2% of all 2004 cars. The rest were advisories or minor defects.

  Rough price £50–£200 our estimate

  At the viewing: Look for cracked or bulging rubber hoses behind the wheels and in the engine bay.

Common 2004 Mercedes-Benz A-Class diesel MOT failures and advisories

The share of 2004 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
  56% 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
  50% 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
  34% 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
  19% 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
  15% 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 2004 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 2.2× as often on the 2004 Mercedes-Benz A-Class diesel as on other cars the same age.)
2. Any recent work on the shock absorbers? (Flagged at MOT 2.9× as often on the 2004 Mercedes-Benz A-Class diesel as on other cars the same age.)
3. Any recent work on the steering rack inner joints? (Flagged at MOT 3.8× as often on the 2004 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?