At a Glance
The Mercedes-benz W123 has 45 identified common problems across 1 generation, with the W123 (1975-1986) being the most affected generation and brakes the most common problem category. Based on 89K MOT tests from DVSA data.
Problems are patterns in the DVSA data that occur significantly more often on a specific model than the UK average — confirmed at 99% statistical confidence. Read our DVSA MOT data methodology →
Below: generation-by-generation comparison of Mercedes-benz W123 common problems, MOT failure types, and pass-rate data drawn from DVSA records. Click any generation to see fuel- and engine-specific fault patterns, mileage-banded repair guidance, and the most common MOT failures testers record.
MOT Tests & Failures by Generation
Mercedes-benz W123 generations by MOT tests, failures, and identified problems from DVSA data
Hover over each bar for a full breakdown. Tap any bar to view that generation's problems.
Showing total MOT tests, failures, and known problems per make. Hover over each bar for a full breakdown.
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Browse Mercedes-benz W123 Generations
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Most Common Mercedes-benz W123 MOT Failures
Every reason Mercedes-benz W123 vehicles fail their MOT, ranked by frequency. Select an individual year to see only that year’s failures, or stay on ‘All time’ for the combined picture across our 20 years of DVSA data. Scroll inside the table for the full list.
| # | Failure | % of failures |
|---|---|---|
| 1 | Tyre tread depth below limit | 12.51% |
| 2 | Suspension joint or bush worn | 8.69% |
| 3 | Stop lamp not working | 6.28% |
| 4 | Number plate lamp not working | 6.27% |
| 5 | Tyre condition | 5.92% |
| 6 | Track rod end worn | 4.53% |
| 7 | Front lamp not working | 4.38% |
| 8 | Headlamp aim defect | 3.71% |
| 9 | Brake performance below minimum | 3.59% |
| 10 | Brake pads or linings worn | 2.85% |
| 11 | Suspension mounting corroded | 2.81% |
| 12 | Exhaust system fault | 2.33% |
| 13 | Brake hydraulic component worn | 2.25% |
| 14 | Brake disc or drum worn | 1.87% |
| 15 | Windscreen washer not working | 1.62% |
| 16 | Chassis condition | 1.55% |
| 17 | Wiper blades deteriorated | 1.54% |
| 18 | Front suspension fault | 1.35% |
| 19 | Body corrosion or damage | 1.33% |
| 20 | Position lamp not working | 1.31% |
| 21 | Rear suspension fault | 1.30% |
| 22 | Ball joint dust cover split | 1.17% |
| 23 | Catalytic converter efficiency low | 1.12% |
| 24 | Windscreen damage affecting view | 1.04% |
| 25 | Coil spring broken or corroded | 0.94% |
| 26 | Indicator fault | 0.84% |
| 27 | Headlamp fault | 0.81% |
| 28 | Horn not working | 0.73% |
| 29 | Parking brake performance below minimum | 0.73% |
| 30 | Rigid brake pipe corroded or damaged | 0.72% |
| 31 | Mirror damaged or missing | 0.72% |
| 32 | Driveshaft fault | 0.69% |
| 33 | Fog lamp not working | 0.62% |
| 34 | Shock absorber worn or leaking | 0.61% |
| 35 | Rear lamp not working | 0.59% |
| 36 | Front suspension joint worn | 0.49% |
| 37 | Subframe mounting corroded | 0.49% |
| 38 | Flexible brake hose damaged | 0.46% |
| 39 | Vehicle structure corrosion | 0.44% |
| 40 | Brake pedal movement restricted | 0.41% |
| 41 | Spring mounting corroded | 0.33% |
| 42 | Fuel pipe corroded or damaged | 0.31% |
| 43 | ABS fault | 0.27% |
| 44 | Suspension arm worn or corroded | 0.26% |
| 45 | Seat belt condition | 0.26% |
| 46 | Brake caliper fault | 0.24% |
| 47 | Battery loose or leaking | 0.23% |
| 48 | Dashboard warning lamp fault | 0.23% |
| 49 | Power steering pipe or hose leaking | 0.23% |
| 50 | Drag link end worn | 0.22% |
| 51 | Parking brake condition | 0.21% |
| 52 | Spark ignition emissions above threshold | 0.20% |
| 53 | Electrical switch fault | 0.20% |
| 54 | Brake pedal fault | 0.19% |
| 55 | Fuel hose damaged or leaking | 0.18% |
| 56 | Exhaust emissions above threshold (non-catalyst) | 0.18% |
| 57 | Subframe corrosion or damage | 0.17% |
| 58 | Wheel bearing worn | 0.17% |
| 59 | Handbrake cable fault | 0.16% |
| 60 | Steering lock fault | 0.16% |
| 61 | Suspension linkage fault | 0.16% |
| 62 | Power steering pump fault | 0.16% |
| 63 | King pin or swivel pin worn | 0.14% |
| 64 | Steering free play excessive | 0.13% |
| 65 | MacPherson strut worn | 0.13% |
| 66 | Steering box fault | 0.12% |
| 67 | Rear fog lamp not working | 0.11% |
| 68 | Bonded suspension condition | 0.11% |
| 69 | Bonnet catch or hinge fault | 0.09% |
| 70 | Suspension unit fault | 0.09% |
| 71 | Steering intermediate drop arm worn | 0.09% |
| 72 | Fuel cap damaged or missing | 0.09% |
| 73 | Propshaft fault | 0.09% |
| 74 | Speedometer fault | 0.09% |
| 75 | Driver seat fault | 0.09% |
| 76 | Anti-roll bar worn or corroded | 0.08% |
| 77 | Rear reflector damaged or missing | 0.08% |
| 78 | Tyre size or type not matched | 0.08% |
| 79 | Brake fluid leak | 0.08% |
| 80 | Steering damper fault | 0.08% |
| 81 | Engine oil leak | 0.07% |
| 82 | Tyre valve stem damaged | 0.07% |
| 83 | Brake lever fault | 0.07% |
| 84 | Brake master cylinder or servo mounting fault | 0.07% |
| 85 | Body security fault | 0.06% |
| 86 | Steering coupling worn | 0.06% |
| 87 | Steering arm worn | 0.05% |
| 88 | Steering lock stop fault | 0.05% |
| 89 | Steering column fault | 0.05% |
| 90 | Brake air or vacuum system fault | 0.05% |
| 91 | Electrical wiring fault | 0.05% |
| 92 | Compression ignition emissions above threshold | 0.05% |
| 93 | Headlamp levelling device fault | 0.05% |
| 94 | Boot lid damaged or insecure | 0.05% |
| 95 | Steering rack fault | 0.05% |
| 96 | Brake fluid warning light on | 0.04% |
| 97 | Vehicle floor corroded | 0.04% |
| 98 | Exhaust leak | 0.04% |
| 99 | Steering operation fault | 0.04% |
| 100 | Airbag warning light on | 0.04% |
| 101 | Brake fluid level low or contaminated | 0.04% |
| 102 | Power steering ram fault | 0.04% |
| 103 | Handbrake mechanism or mounting fault | 0.03% |
| 104 | Steering drive system fault | 0.03% |
| 105 | Brake back plate corroded or damaged | 0.03% |
| 106 | Transmission oil leak | 0.03% |
| 107 | Electronic stability control fault | 0.03% |
| 108 | Fuel tank corroded or leaking | 0.03% |
| 109 | Passenger seat fault | 0.03% |
| 110 | Handbrake lever fault | 0.02% |
| 111 | Tie bar or rod worn or corroded | 0.02% |
| 112 | Trailing arm worn or corroded | 0.02% |
| 113 | Hydraulic suspension accumulator fault | 0.02% |
| 114 | Radius arm worn or corroded | 0.02% |
| 115 | Steering shaft fault | 0.02% |
| 116 | Tailgate damaged or insecure | 0.02% |
| 117 | Brake wheel cylinder fault | 0.02% |
| 118 | Bumper damaged or insecure | 0.02% |
| 119 | Engine mounting worn or broken | 0.02% |
| 120 | Steering wheel damaged or insecure | 0.02% |
| 121 | Suspension retaining or locking device fault | 0.02% |
| 122 | Brake cable, rod, lever or linkage fault | 0.02% |
| 123 | Brake linkage mounting fault | 0.02% |
| 124 | Load sensing valve fault | 0.02% |
| 125 | Towbar fault | 0.02% |
| 126 | Air suspension levelling valve fault | 0.01% |
| 127 | Brake master cylinder fault | 0.01% |
| 128 | Indicator warning light fault | 0.01% |
| 129 | Main beam warning light fault | 0.01% |
| 130 | Brake valve fault | 0.01% |
| 131 | Outline marker lamp not working | 0.01% |
| 132 | Suspension coupling worn | 0.01% |
| 133 | Additional braking device fault | <0.01% |
| 134 | Brake fluid reservoir fault | <0.01% |
| 135 | Driver door fault | <0.01% |
| 136 | Semaphore indicator fault | <0.01% |
| 137 | Torque or reaction arm worn | <0.01% |
| 138 | Dip switch fault | <0.01% |
| 139 | Exhaust heat shield or sound insulation damaged | <0.01% |
| 140 | Front passenger door fault | <0.01% |
| 141 | Hand-operated brake valve condition | <0.01% |
| 142 | Hydraulic brake cylinder fault | <0.01% |
| 143 | Leaf spring broken or corroded | <0.01% |
| 144 | Access panel damaged or insecure | <0.01% |
| 145 | Axle beam corroded or cracked | <0.01% |
| 146 | Hydraulic fluid leak | <0.01% |
| 147 | Stub axle worn | <0.01% |
| 148 | Suspension air bellows damaged | <0.01% |
| 149 | Suspension linkage attachment bracket or mounting corroded | <0.01% |
| 150 | Body strengthening plate corroded | <0.01% |
| 151 | Brake clevis joint worn | <0.01% |
| 152 | Brake pressure or vacuum buildup insufficient | <0.01% |
| 153 | Brake servo fault | <0.01% |
| 154 | CV joint worn | <0.01% |
| 155 | Front fog lamp not working | <0.01% |
| 156 | Hazard warning light fault | <0.01% |
| 157 | Leaf spring slipper worn | <0.01% |
| 158 | Mirror or camera fault | <0.01% |
| 159 | Rear fog lamp warning light fault | <0.01% |
| 160 | Seat belt anchorage fault | <0.01% |
| 161 | Spare wheel fault | <0.01% |
| 162 | Steering head bearings worn | <0.01% |
| 163 | Transmission drive belt fault | <0.01% |
| 164 | Undertray damaged or missing | <0.01% |
Showing all 164 reasons — scroll inside the table for the full list.
Mercedes-benz W123 MOT Failures by Category
Total MOT failure occurrences for the Mercedes-benz W123, grouped by category. Same data as the failures table above — just sliced by category instead of fault title. Hover a slice for the top failures in each category.
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Frequently Asked Questions
What are the most common Mercedes-benz W123 problems?
Based on analysis of 89K Mercedes-benz W123 MOT tests from DVSA data, we have 45 identified common problems across 1 generation. The most frequently flagged issue is "Brake hydraulic component worn". Brakes is the most common problem category.
Which Mercedes-benz W123 generation has the most problems?
The Mercedes-benz W123 W123 (1975-1986) (1975–1986) has the highest number of identified common problems (62). Click the generation card above for the full breakdown.
How is this data calculated?
We analyse anonymised DVSA MOT test records under the Open Government Licence. An issue is classified as a "Common Problem" when it occurs significantly more often on a specific model than the UK average, confirmed at 99% statistical confidence. Read the full methodology page for details.
Can I report a problem with my Mercedes-benz W123?
Yes — use the "Tell Us About Your Problem" form on this page. Your report helps other Mercedes-benz W123 owners spot problems early. All submissions are reviewed before being added to the public database.
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