Used car guide

1999 Mercedes-Benz SL: common problems and what to check

What gets flagged at MOT on 1999 Mercedes-Benz SLs, from 525 tests in 2025, plus known faults and what to look at before you buy one.

525MOT tests in 2025
82%pass first time (all 1999 cars: 65%)
3,200typical miles a year
4.1×the usual rate for ball joint dust cover

What stands out

Parts flagged at MOT more often on 1999 Mercedes-Benz SLs than on all cars registered in 1999.

  • Ball joint dust cover4.1× usual
    Mercedes-Benz SL
    15.2% All 1999 cars
    3.7%

    Failed outright at MOT: 4.6%, against 1.2% of all 1999 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.

Better than most

Tread depth: 5.5% here, against 11.2% of all 1999 cars.

By area

The share of 1999 Mercedes-Benz SL MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    30% 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.

  • Brakes
    25% 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.

  • Lights and electrics
    19% 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
    16% 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.

  • Oil and fluid leaks
    13% of testsRough price £80–£600

    At the viewing: Look under the engine and on the ground where the car is usually parked for fresh oil or fluid.

  • 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.

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Other years

YearMOT testsMost flagged
2019340Tyres 19%
2018405Tyres 19%
2017640Tyres 23%
2016766Tyres 21%
2015783Tyres 22%
20141,074Tyres 23%
20131,149Tyres 22%
2012415Tyres 21%
2011249Tyres 23%
2010352Tyres 25%
2009459Brakes 24%
2008743Brakes 23%
2007771Brakes 23%
2006778Brakes 25%
20051,079Brakes 24%
20041,742Brakes 24%
20032,242Suspension 25%
2002912Brakes 26%
2001288Suspension 25%
2000475Suspension 28%
1998681Suspension 27%
1997646Suspension 26%
1996593Brakes 26%
1995535Suspension 26%
1994378Brakes 27%
1993156Brakes 26%
1992116Suspension 27%
1991100Suspension 29%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 1999 Mercedes-Benz SLs registered in 1999. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score