Bsa B31 Reliability, MOT Pass Rate & Common Faults
Free Bsa B31 car check
Is the Bsa B31 reliable? We analysed 3,419 real MOT tests across 885 vehicles to find out.
Got a specific Bsa B31? Enter the reg for a free check:
The Bsa B31 is above average for reliability based on real UK MOT data. Common problems include horn not working, roller brake test the less effective brake control does not achieve an efficiency of 25%. and stop lamp does not illuminate immediately a brake applies. Here's everything you need to know before buying a used Bsa B31.
Bsa B31 Number Plates
Number plates registered to a Bsa B31. Click on any registration for full vehicle details — including MOT history, mileage records, previous owners and damage history.
Bsa B31 MOT Pass Rate by Year
How likely is a Bsa B31 to pass its MOT? Here's the pass rate for each registration year, newest first.
Bsa B31 Problems — What Goes Wrong?
The most common reasons a Bsa B31 fails its MOT, ranked by how often they occur. Check for these problems before you buy.
Bsa B31 Mileage — What's Normal?
How many miles does a typical Bsa B31 owner drive per year? Use this to check if a car you're looking at has suspiciously low or high mileage.
Bsa B31 MOT Data by Registration Year
Full breakdown of pass rate and mileage for each year. Use this to compare the Bsa B31 year you're looking at.
| Year | Tests | Pass Rate | Low Mi. | Typical Mi. | High Mi. |
|---|---|---|---|---|---|
| 2002 | 63 | 93.7% | 1,266 | 4,160 | 10,469 |
| 1996 | 54 | 90.7% | 625 | 7,264 | 17,804 |
| 1991 | 54 | 98.1% | 3,431 | 13,019 | 29,037 |
| 1989 | 59 | 84.7% | 29,051 | 33,654 | 60,720 |
| 1959 | 187 | 91.4% | 4,412 | 24,490 | 42,359 |
| 1958 | 156 | 90.4% | 4,563 | 13,686 | 37,699 |
| 1957 | 139 | 92.8% | 8,711 | 37,681 | 49,575 |
| 1956 | 355 | 94.1% | 3,564 | 17,248 | 47,703 |
| 1955 | 310 | 95.2% | 5,418 | 30,815 | 48,548 |
| 1954 | 256 | 93.4% | 2,130 | 14,373 | 48,864 |
| 1953 | 192 | 90.1% | 10,932 | 30,474 | 57,730 |
| 1952 | 98 | 86.7% | 5,505 | 13,116 | 32,668 |
| 1950 | 186 | 94.1% | 3,422 | 17,126 | 40,186 |
| 1949 | 133 | 91.0% | 3,666 | 13,616 | 38,678 |
| 1946 | 62 | 96.8% | 2,085 | 13,267 | 54,609 |
How Long Does a Bsa B31 Last?
Based on 885 Bsa B31 vehicles on UK roads.
Bsa B31 Mileage Distribution
Total mileage recorded across all Bsa B31 MOT tests. If the car you're looking at is above the 75th percentile, it's done more miles than most.
Best Year to Buy a Used Bsa B31
Based on MOT pass rates across all registration years with sufficient test data.
98.1% MOT pass rate from 54 tests
84.7% MOT pass rate from 59 tests
The best year to buy a used Bsa B31 is 1991, which has the highest MOT pass rate at 98.1% across 54 tests. The 1989 model year has the lowest pass rate at 84.7% — if you're looking at one from that year, budget for potential repairs and get a thorough pre-purchase inspection.
How Does the Bsa B31 Compare?
MOT pass rates compared to similar models. Click any model for the full breakdown.
| Model | Pass Rate | Tests | Typical Mileage | Lifespan |
|---|---|---|---|---|
| Bsa B31 THIS CAR | 92.5% | 3,419 | 15,189 mi | 80 yrs |
| Bsa A10 | 92.2% | 10,105 | 12,338 mi | 74 yrs |
| Bsa Bantam | 89.9% | 7,723 | 13,212 mi | 77 yrs |
| Bsa C15 | 90.2% | 6,096 | 14,541 mi | 67 yrs |
| Fiat Motorcaravan | 79.1% | 5,061 | 37,427 mi | 35 yrs |
Compared to the Bsa A10 (92.2% pass rate) and the Bsa Bantam (89.9% pass rate), the Bsa B31 outperforms both on MOT reliability.
Found a Bsa B31 you like?
Run a full vehicle history check on the specific car. See finance, stolen, write-off, mileage and MOT data for that exact vehicle.
Check a specific Bsa B31Should you buy a used Bsa B31?
The Bsa B31 has an overall MOT pass rate of 92.5% across 3,419 real MOT tests — comfortably above the UK average, which puts it among the more reliable models on UK roads.
The most common problems on the Bsa B31 are horn not working (17 recorded failures), roller brake test the less effective brake control does not achieve an efficiency of 25%. (12), and stop lamp does not illuminate immediately a brake applies (11). These are the faults most likely to cause an MOT failure on this model, so check for them carefully on any test drive or pre-purchase inspection. Many are wear-and-tear items that can be budgeted for, but a car that's already failing on multiple fronts may signal neglected maintenance.
A typical Bsa B31 owner drives around 210 miles per year. If the car you're looking at is significantly above this, expect more wear on suspension, brakes and tyres. If it's well below, the vehicle may have been sitting unused — check for perished rubber, corroded discs and stale fluids.
In terms of longevity, most Bsa B31 models stay on UK roads for around 80 years — a strong showing that suggests solid build quality and readily available parts. If you're buying one that's already approaching that window, the data suggests it has plenty of life left provided it's been maintained.
Before committing to a purchase, we recommend running a full vehicle history check on the specific car. This will reveal any outstanding finance, stolen markers, write-off history and mileage discrepancies that the seller may not disclose — and that the MOT data alone can't tell you.