Mercedes Benz
R Class
5,262 MOT tests analysed. lands in the middle of the pack — here's where R Classs pass, fail, and end up on the retest sheet.
That's 1.6 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
79.1%
Pass-after-fix
4.0%
Fail
15.6%
Avg miles
115,130
Pass + Pass-after-fix + Fail = 100%
Diesel cars registered before September 2015 are typically pre-Euro 6 — subject to daily charges in London ULEZ (£12.50), Birmingham CAZ (£8), Bristol CAZ (£9), and Glasgow LEZ. Daily charges if driven in the zone: London £12.50 · Birmingham £8.00 · Bristol £9.00 .
The picture
R-Class: middle-of-the-pack on first-time pass
Across 2,952 MOT tests, the R-Class returns 74.0% first-time pass — below the UK fleet average. The single most-logged Major fail is a split CV-joint boot. A missing CV-joint boot and windscreen damage round out the top three. Average tested mileage sits at 119,558, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
ABI Insurance Group
Group 26–38
Above average — worth comparing quotes before buying. Lower groups cost less to insure; UK fleet average is around Group 22.
Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →
26–38
out of 50
Top ten reasons for rejection.
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- 01
A transmission shaft constant velocity joint boot severely deteriorated
476 occurrences · 9.0% of tests
- 02
A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc
146 occurrences · 2.8% of tests
- 03
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
118 occurrences · 2.2% of tests
- 04
Brake pipe damaged or excessively corroded
92 occurrences · 1.7% of tests
- 05
A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
76 occurrences · 1.4% of tests
- 06
A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
73 occurrences · 1.4% of tests
- 07
Tyre tread depth not in accordance with the requirements
73 occurrences · 1.4% of tests
- 08
Parking brake efficiency below minimum requirement
73 occurrences · 1.4% of tests
- 09
Headlamp reflector or lens slightly defective
59 occurrences · 1.1% of tests
- 10
A tyre cords visible or damaged
40 occurrences · 0.8% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 2 failures
£48–£125
If every one of this R Class's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
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Tools that pre-empt a retest.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
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Recall history
6 UK recalls on record.
The R Class has 6 official UK vehicle recalls covering defect details, remedies, and affected build dates.
Buying or keeping a R Class?
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a R Class and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.