MOT History from tests of petrol MERCEDES BENZ 420s year 1986

Review the list of common MERCEDES BENZ 420 failures below or to perform a specific mot history check on your MERCEDES BENZ then use our popular KnowYourCar service

mot history

Pass percent:74.02%

(The average a petrol MERCEDES BENZ 420 year 1986 passes without issue)

Based on:3,083 MOT Tests

Most common failures	No# failures
Headlamp aim out of alignment	207
Brake pipe excessively corroded	99
Registration plate lamp issues	95
Windscreen wiper does not clear the windscreen effectively	90
Exhaust emissions carbon monoxide content excessive \|7.3.B.1a\|	58
Brake hose excessively deteriorated	51
Parking brake: efficiency below requirements \|3.7.B.7\|	46
Registration plate issues	46
Brakes imbalanced across an axle	44
Nearside Rear Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	41
Offside Rear Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	38
Nearside Front Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	30
Offside Rear fog lamp not working \|1.3.2b\|	30
Anti-lock braking system warning lamp indicates an ABS fault	27
Rear brake binding	26
Rear parking brake recording little or no effort	26
Offside Front Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	26
Exhaust engine idle speed too high \|7.3.A.2a\|	18
Offside Front position lamp\|s\| not working \|1.1.A.3b\|	18
Hazard warning switch faulty \|1.4.B.1d\|	17
Rear fog lamp tell tale not working \|1.3.1b\|	16
Front Exhaust has a major leak of exhaust gases \|7.1.2\|	16
Nearside Rear Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	15
Nearside Front position lamp\|s\| not working \|1.1.A.3b\|	15
Exhaust emissions hydrocarbon content excessive \|7.3.B.1b\|	14
Nearside Stop lamp not working \|1.2.1b\|	13
Horn not working \|1.6.2a\|	13
Hazard warning lamps not flashing in phase, with ignition on \|1.4.B.1f\|	13
Nearside Front Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	13
Exhaust has a major leak of exhaust gases \|7.1.2\|	13
Centre Exhaust has a major leak of exhaust gases \|7.1.2\|	12
Offside Stop lamp not working \|1.2.1b\|	12
Mechanical brake component has restricted free movement	12
Offside front brake binding \|3.7.B.1\|	12
Rear Mechanical brake component has restricted free movement	11
Parking brake lever has no reserve travel \|3.1.6b\|	11
Emissions not tested \|7.0\|	11
Offside Rear Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	11
Offside Rear position lamp\|s\| not working \|1.1.A.3b\|	10
Rear Exhaust mounting missing \|7.1.1b\|	10
Rear Exhaust has a major leak of exhaust gases \|7.1.2\|	10
Service brake: efficiency below requirements \|3.7.B.7\|	10
Hazard warning lamps not flashing in phase, with ignition off \|1.4.B.1f\|	10
Front brake application uneven	10
Nearside front brake binding \|3.7.B.1\|	10
Offside Front Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	9
Centre Exhaust system not adequately supported \|7.1.1\|	9
Nearside Rear position lamp\|s\| not working \|1.1.A.3b\|	9
Nearside Rear Stop lamp not working \|1.2.1b\|	9
Offside Front Lower Suspension arm ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt \|2.4.G.2\|	8
Nearside Rear Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	8
Offside Headlamp not working on main beam \|1.7.5a\|	8
Nearside Front Seat belt anchorage prescribed area is excessively corroded \|5.2.6\|	8
Direction indicators not working \|1.4.A.2c\|	8
Power steering component\|s\| leaking \|2.3.3b\|	8
Offside Rear Stop lamp not working \|1.2.1b\|	8
Nearside Front suspension has excessive play in a lower suspension ball joint \|2.5.B.1a\|	7
Offside Front suspension has excessive play in a lower suspension ball joint \|2.5.B.1a\|	7
Rear Exhaust system not adequately supported \|7.1.1\|	7
Offside Front Front position lamp\|s\| not working \|1.1.A.3b\|	7
Offside Front Lower Suspension arm corroded and seriously weakened \|2.4.G.1\|	7
Exhaust system not adequately supported \|7.1.1\|	7
Offside Front front brake binding \|3.7.B.1\|	7
Offside Headlamp not working on dipped beam \|1.7.5a\|	7
Offside Rear Rear fog lamp not working \|1.3.2b\|	7
Exhaust emissions carbon monoxide content excessive (8.2.1.2 (b))	7
Nearside Front Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	6
Offside Front Suspension arm corroded and seriously weakened \|2.4.G.1\|	6
Nearside Rear Suspension spring mounting prescribed area is excessively corroded \|2.4.A.3\|	6
Windscreen has damage	6
Offside Rear position lamp\|s\| excessively deteriorated so that it is not visible from a reasonable distance \|1.1.A.3d\|	6
Offside Rear Shock absorber has a serious fluid leak \|2.7.3\|	6
Exhaust emissions hydrocarbon content excessive (8.2.1.2 (b))	6
Nearside Front Lower Suspension arm ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt \|2.4.G.2\|	5
Nearside Front Upper Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	5
Rear fog lamp not working \|1.3.2b\|	5
Anti-lock braking system warning lamp does not illuminate \|3.4.1b\|	5
Offside Front Seat belt anchorage prescribed area is excessively corroded \|5.2.6\|	5
Rear brake application uneven	5
Offside Rear Suspension spring mounting prescribed area is excessively corroded \|2.4.A.3\|	5
Nearside Side repeater not working \|1.4.A.2c\|	5
Offside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt \|5.3.4 \|b\| \|ii\|\|	5
Battery insecure \|1.9.1\|	5
Front Steering damper leaking oil \|2.2.C.1f\|	5
Nearside Front Brake hose bulging under pressure \|3.6.B.3\|	5
Offside Front Brake hose bulging under pressure \|3.6.B.3\|	5
Offside Front Lower Suspension arm ball joint dust cover excessively damaged so that it no longer prevents the ingress of dirt \|2.4.G.2\|	5
Steering box has a significant oil leak \|2.2.D.2e\|	4
Nearside Headlamp not working on main beam \|1.7.5a\|	4
Offside Front Front suspension has excessive play in a lower suspension ball joint \|2.5.B.1a\|	4
Nearside Steering pivot point has excessive play \|2.2.B.1g\|	4
Offside Front Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	4
Brake performance not tested \|3.7.A.1\|	4
Offside Front Headlamp not working on main beam \|1.7.5a\|	4
Nearside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt \|5.3.4 \|b\| \|ii\|\|	4
Fuel system component leaking \|7.2.3\|	4
Offside Side repeater not working \|1.4.A.2c\|	4
Nearside Front front brake binding \|3.7.B.1\|	4
Nearside Front Exhaust has a major leak of exhaust gases \|7.1.2\|	4
Offside Front coil spring fractured \|2.4.C.1a\|	4
Offside Rear Body has a sharp edge caused by corrosion \|6.1.C.1\|	4
Offside Front Anti-roll bar linkage fractured \|2.4.G.1\|	4
Nearside Side repeater insecure \|1.4.A.2b\|	4
Nearside Rear Brake hose bulging under pressure \|3.6.B.3\|	4
Offside Front Headlamp not working on dipped beam \|1.7.5a\|	4
Nearside Rear position lamp\|s\| excessively deteriorated so that it is not visible from a reasonable distance \|1.1.A.3d\|	4
Nearside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt (5.3.4 (b) (ii))	4
Nearside Front Steering pivot point has excessive play \|2.2.B.1g\|	3
Offside Front Exhaust has a major leak of exhaust gases \|7.1.2\|	3
Offside Front Body has a sharp edge caused by corrosion \|6.1.C.1\|	3
Nearside Front Suspension arm corroded and seriously weakened \|2.4.G.1\|	3
Brake hose damaged	3
Nearside Headlamp not working on dipped beam \|1.7.5a\|	3
Offside Front Sub-frame rubber bush deteriorated resulting in excessive movement \|2.4.G.2\|	3
Nearside Rear Exhaust system not adequately supported \|7.1.1\|	3
Offside Front Vehicle structure has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	3
Brake hose has insufficient room to move	3
Nearside Rear Shock absorber has a serious fluid leak \|2.7.3\|	3
Nearside Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	3
Offside Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	3
Nearside Front Upper Suspension arm ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt \|2.4.G.2\|	3
Nearside Headlamp aim beam image kick up to the offside \|1.8\|	3
Power steering pump leaking from a failed seal \|2.3.3b\|	3
Rear Exhaust has part of the system excessively deteriorated \|7.1.1a\|	3
Nearside Exhaust has a major leak of exhaust gases \|7.1.2\|	3
Nearside Front coil spring fractured \|2.4.C.1a\|	3
Nearside Front Service brake excessively binding \|1.2.1 \|f\|\|	3
Offside Rear Service brake excessively binding \|1.2.1 \|f\|\|	3
Offside Front Side repeater not working \|1.4.A.2c\|	3
Exhaust emissions carbon monoxide content excessive \|8.2.1.2 \|b\|\|	3
Nearside Front Lower Suspension arm ball joint dust cover excessively damaged so that it no longer prevents the ingress of dirt \|2.4.G.2\|	3
An item not tested \|Manual\|	3
Offside Rear Seat belt anchorage prescribed area is excessively corroded \|5.2.6\|	3
Offside Front Vehicle structure has excessive corrosion which adversely affects braking or steering \|6.1.A.1\|	3
Hazard warning lamps inoperative \|1.4.B.1b\|	3
Windscreen has a sticker or other obstruction encroaching into the swept area by more than 40mm outside zone `A` \|8.3.1e\|	3
Offside Front coil spring incomplete \|2.4.C.1a\|	3
Nearside Track rod end ball joint has excessive play \|2.2.B.1f\|	3
Windscreen washer not working	3
Offside Front Position lamp not working (4.2.1 (a) (ii))	3
Offside Rear Position lamp not working (4.2.1 (a) (ii))	3
Parking brake efficiency below requirements (1.4.2 (a) (i))	3
Offside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt (5.3.4 (b) (ii))	3

We get to these numbers by trawling through over 1 billion MOT test results since 2004 and crunched the numbers. We remove anything to do with Tyres, as they are model independent and group together common non-model specific issues. We are trying to get to a picture of what models have what issues.

Please note: We take the data from the DVSA. This data is raw and can contain typos and spelling mistakes that garages may have entered while recording a MOT result. Specifically miss-match on names of models and makes. We are constantly cleaning the data so bear with the odd issue.

Got suggestions? We’re improving this section all the time. If you have any suggestions, please let us know.

Most common failures	No# failures
Headlamp aim out of alignment	207
Brake pipe excessively corroded	99
Registration plate lamp issues	95
Windscreen wiper does not clear the windscreen effectively	90
Exhaust emissions carbon monoxide content excessive \|7.3.B.1a\|	58
Brake hose excessively deteriorated	51
Parking brake: efficiency below requirements \|3.7.B.7\|	46
Registration plate issues	46
Brakes imbalanced across an axle	44
Nearside Rear Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	41
Offside Rear Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	38
Nearside Front Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	30
Offside Rear fog lamp not working \|1.3.2b\|	30
Anti-lock braking system warning lamp indicates an ABS fault	27
Rear brake binding	26
Rear parking brake recording little or no effort	26
Offside Front Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	26
Exhaust engine idle speed too high \|7.3.A.2a\|	18
Offside Front position lamp\|s\| not working \|1.1.A.3b\|	18
Hazard warning switch faulty \|1.4.B.1d\|	17
Rear fog lamp tell tale not working \|1.3.1b\|	16
Front Exhaust has a major leak of exhaust gases \|7.1.2\|	16
Nearside Rear Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	15
Nearside Front position lamp\|s\| not working \|1.1.A.3b\|	15
Exhaust emissions hydrocarbon content excessive \|7.3.B.1b\|	14
Nearside Stop lamp not working \|1.2.1b\|	13
Horn not working \|1.6.2a\|	13
Hazard warning lamps not flashing in phase, with ignition on \|1.4.B.1f\|	13
Nearside Front Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	13
Exhaust has a major leak of exhaust gases \|7.1.2\|	13
Centre Exhaust has a major leak of exhaust gases \|7.1.2\|	12
Offside Stop lamp not working \|1.2.1b\|	12
Mechanical brake component has restricted free movement	12
Offside front brake binding \|3.7.B.1\|	12
Rear Mechanical brake component has restricted free movement	11
Parking brake lever has no reserve travel \|3.1.6b\|	11
Emissions not tested \|7.0\|	11
Offside Rear Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	11
Offside Rear position lamp\|s\| not working \|1.1.A.3b\|	10
Rear Exhaust mounting missing \|7.1.1b\|	10
Rear Exhaust has a major leak of exhaust gases \|7.1.2\|	10
Service brake: efficiency below requirements \|3.7.B.7\|	10
Hazard warning lamps not flashing in phase, with ignition off \|1.4.B.1f\|	10
Front brake application uneven	10
Nearside front brake binding \|3.7.B.1\|	10
Offside Front Subframe mounting prescribed area is excessively corroded \|2.4.A.3\|	9
Centre Exhaust system not adequately supported \|7.1.1\|	9
Nearside Rear position lamp\|s\| not working \|1.1.A.3b\|	9
Nearside Rear Stop lamp not working \|1.2.1b\|	9
Offside Front Lower Suspension arm ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt \|2.4.G.2\|	8
Nearside Rear Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	8
Offside Headlamp not working on main beam \|1.7.5a\|	8
Nearside Front Seat belt anchorage prescribed area is excessively corroded \|5.2.6\|	8
Direction indicators not working \|1.4.A.2c\|	8
Power steering component\|s\| leaking \|2.3.3b\|	8
Offside Rear Stop lamp not working \|1.2.1b\|	8
Nearside Front suspension has excessive play in a lower suspension ball joint \|2.5.B.1a\|	7
Offside Front suspension has excessive play in a lower suspension ball joint \|2.5.B.1a\|	7
Rear Exhaust system not adequately supported \|7.1.1\|	7
Offside Front Front position lamp\|s\| not working \|1.1.A.3b\|	7
Offside Front Lower Suspension arm corroded and seriously weakened \|2.4.G.1\|	7
Exhaust system not adequately supported \|7.1.1\|	7
Offside Front front brake binding \|3.7.B.1\|	7
Offside Headlamp not working on dipped beam \|1.7.5a\|	7
Offside Rear Rear fog lamp not working \|1.3.2b\|	7
Exhaust emissions carbon monoxide content excessive (8.2.1.2 (b))	7
Nearside Front Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	6
Offside Front Suspension arm corroded and seriously weakened \|2.4.G.1\|	6
Nearside Rear Suspension spring mounting prescribed area is excessively corroded \|2.4.A.3\|	6
Windscreen has damage	6
Offside Rear position lamp\|s\| excessively deteriorated so that it is not visible from a reasonable distance \|1.1.A.3d\|	6
Offside Rear Shock absorber has a serious fluid leak \|2.7.3\|	6
Exhaust emissions hydrocarbon content excessive (8.2.1.2 (b))	6
Nearside Front Lower Suspension arm ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt \|2.4.G.2\|	5
Nearside Front Upper Suspension component mounting prescribed area is excessively corroded \|2.4.A.3\|	5
Rear fog lamp not working \|1.3.2b\|	5
Anti-lock braking system warning lamp does not illuminate \|3.4.1b\|	5
Offside Front Seat belt anchorage prescribed area is excessively corroded \|5.2.6\|	5
Rear brake application uneven	5
Offside Rear Suspension spring mounting prescribed area is excessively corroded \|2.4.A.3\|	5
Nearside Side repeater not working \|1.4.A.2c\|	5
Offside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt \|5.3.4 \|b\| \|ii\|\|	5
Battery insecure \|1.9.1\|	5
Front Steering damper leaking oil \|2.2.C.1f\|	5
Nearside Front Brake hose bulging under pressure \|3.6.B.3\|	5
Offside Front Brake hose bulging under pressure \|3.6.B.3\|	5
Offside Front Lower Suspension arm ball joint dust cover excessively damaged so that it no longer prevents the ingress of dirt \|2.4.G.2\|	5
Steering box has a significant oil leak \|2.2.D.2e\|	4
Nearside Headlamp not working on main beam \|1.7.5a\|	4
Offside Front Front suspension has excessive play in a lower suspension ball joint \|2.5.B.1a\|	4
Nearside Steering pivot point has excessive play \|2.2.B.1g\|	4
Offside Front Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	4
Brake performance not tested \|3.7.A.1\|	4
Offside Front Headlamp not working on main beam \|1.7.5a\|	4
Nearside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt \|5.3.4 \|b\| \|ii\|\|	4
Fuel system component leaking \|7.2.3\|	4
Offside Side repeater not working \|1.4.A.2c\|	4
Nearside Front front brake binding \|3.7.B.1\|	4
Nearside Front Exhaust has a major leak of exhaust gases \|7.1.2\|	4
Offside Front coil spring fractured \|2.4.C.1a\|	4
Offside Rear Body has a sharp edge caused by corrosion \|6.1.C.1\|	4
Offside Front Anti-roll bar linkage fractured \|2.4.G.1\|	4
Nearside Side repeater insecure \|1.4.A.2b\|	4
Nearside Rear Brake hose bulging under pressure \|3.6.B.3\|	4
Offside Front Headlamp not working on dipped beam \|1.7.5a\|	4
Nearside Rear position lamp\|s\| excessively deteriorated so that it is not visible from a reasonable distance \|1.1.A.3d\|	4
Nearside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt (5.3.4 (b) (ii))	4
Nearside Front Steering pivot point has excessive play \|2.2.B.1g\|	3
Offside Front Exhaust has a major leak of exhaust gases \|7.1.2\|	3
Offside Front Body has a sharp edge caused by corrosion \|6.1.C.1\|	3
Nearside Front Suspension arm corroded and seriously weakened \|2.4.G.1\|	3
Brake hose damaged	3
Nearside Headlamp not working on dipped beam \|1.7.5a\|	3
Offside Front Sub-frame rubber bush deteriorated resulting in excessive movement \|2.4.G.2\|	3
Nearside Rear Exhaust system not adequately supported \|7.1.1\|	3
Offside Front Vehicle structure has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	3
Brake hose has insufficient room to move	3
Nearside Rear Shock absorber has a serious fluid leak \|2.7.3\|	3
Nearside Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	3
Offside Body or chassis has excessive corrosion, seriously affecting its strength within 30cm of the body mountings \|6.1.B.2\|	3
Nearside Front Upper Suspension arm ball joint dust cover excessively deteriorated so that it no longer prevents the ingress of dirt \|2.4.G.2\|	3
Nearside Headlamp aim beam image kick up to the offside \|1.8\|	3
Power steering pump leaking from a failed seal \|2.3.3b\|	3
Rear Exhaust has part of the system excessively deteriorated \|7.1.1a\|	3
Nearside Exhaust has a major leak of exhaust gases \|7.1.2\|	3
Nearside Front coil spring fractured \|2.4.C.1a\|	3
Nearside Front Service brake excessively binding \|1.2.1 \|f\|\|	3
Offside Rear Service brake excessively binding \|1.2.1 \|f\|\|	3
Offside Front Side repeater not working \|1.4.A.2c\|	3
Exhaust emissions carbon monoxide content excessive \|8.2.1.2 \|b\|\|	3
Nearside Front Lower Suspension arm ball joint dust cover excessively damaged so that it no longer prevents the ingress of dirt \|2.4.G.2\|	3
An item not tested \|Manual\|	3
Offside Rear Seat belt anchorage prescribed area is excessively corroded \|5.2.6\|	3
Offside Front Vehicle structure has excessive corrosion which adversely affects braking or steering \|6.1.A.1\|	3
Hazard warning lamps inoperative \|1.4.B.1b\|	3
Windscreen has a sticker or other obstruction encroaching into the swept area by more than 40mm outside zone `A` \|8.3.1e\|	3
Offside Front coil spring incomplete \|2.4.C.1a\|	3
Nearside Track rod end ball joint has excessive play \|2.2.B.1f\|	3
Windscreen washer not working	3
Offside Front Position lamp not working (4.2.1 (a) (ii))	3
Offside Rear Position lamp not working (4.2.1 (a) (ii))	3
Parking brake efficiency below requirements (1.4.2 (a) (i))	3
Offside Front Lower Suspension arm ball joint dust cover no longer prevents the ingress of dirt (5.3.4 (b) (ii))	3

MOT History from tests of petrol MERCEDES BENZ 420s year 1986

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