[gooman]

The BBC has succeeded in an FOI request to VOSA to publish MOT failure rates.

Full story here.

Obviously lots of interesting analysis to be done, but as a first pass in looking at 916s, I selected just the data since 1996 (as we're looking at 916s only here).

GTVs have an average MOT failure rate of 43.4%, peaking at 50.4% for 1996 reg.

Spiders have an average MOT failure rate of 39.6%, peaking at 47.8% for 1996 reg.

It's not easy to work out how this compares against other cars, though the BBC report does have a handy comparator for cars registered in 1997, and GTVs/Spiders from 1997 fall somewhere in the middle of that table.

At a guess, I'd say that the discrepancy between GTVs and Spiders might be due to Spider owners being more likely to treat them as a summer car and doing less mileage per year than a typical GTV owner.

Causes of failure (or advisory), from the most popular down (averaged for both vehicle types) are:

Brakes 43%
Lighting & signalling 25%
Suspension 19%
Tyres 18%
Fuel & exhaust 14%
Drivers view 12% (covers wiper blades, washers, and cracks/chips)

 

[Stu GTV]

I would think that even the average motorist could check brake pads, lights and tyres before presenting a car for the MOT test, and know that it will fail if they are not all within the law. They probably try and get away with it because a re-test is free at most MOT centres, and are prepared to drive an unsafe car to save a few quid.

 

[JFK]

43% failure or advisory for brakes tells a story in itself. Thankfully, touch wood, mine has passed all of its MOT's first time. Being a summer only car does n't always work in a Spider's favour. Lack of winter use can lead to extra oxidisation of electrical contacts and the lower infrequent mileage makes the rear parking brake an iffy MOT item.

 

[gooman]

For comparison ... total average failure rate across *all* data (all makes, models, years) is 35%.

Causes of failure (or advsiory) across all makes, models, years is:

Lighting & signalling 27%
Brakes 25%
Suspension 19%
Tyres 13%
Fuel & exhaust 10%
Drivers view 9%

As JFK rightly points out, it's the failure/advisory rate on brakes that are the biggest anomaly. And I think we'd all guess that it's because they're so poor in the first place that it doesn't take much degradation to make them a failure point on the MOT.

 

[daveypark]

43% failure or advisory for brakes tells a story in itself. Thankfully, touch wood, mine has passed all of its MOT's first time. Being a summer only car does n't always work in a Spider's favour. Lack of winter use can lead to extra oxidisation of electrical contacts and the lower infrequent mileage makes the rear parking brake an iffy MOT item.

My Gtv failed on rear brakes on Monday, plus abs light.

 

[ku$t]

mine failed on my rear brake too.

 

[alfapdent]

My Spider had an advisory on the rear brakes in its 2008 MOT. Everything seemed OK and when it was MOT'd in 2009 the rear brakes had got significantly better (at a different MOT station) and in fact were an easy pass.

It has been said that not all the brake testing equipment gives the same result, or maybe more use of the car helped.