ABS sensor failed car MOT, where do i go next?

RichardD1970

Jakg wrote: »

I don't want to dissuade the OP from getting another opinion (those prices sound ridiculous - and my experience is that with ABS faults many garages would rather replace aimlessly than diagnose), but I can't agree with this statement.

On a car without ABS, the brakes would be set up so that they all locked up around the same point, to give maximum braking performance.

On a car with ABS - or certainly on my last car (MG ZT) this wasn't needed as it has a multi-channel ABS system so it can always stop each wheel as much as possible, irrespective of any front / rear imbalance. Of course when you turn the ABS off, this imbalance is exposed again. This meant it locked up the rear wheels pretty easily and reduced the maximum braking you could apply.

I also haven't seen any manufacturer endorsed document saying it's ok to drive with an inoperable ABS system - irrespective as to the truth of the statement, think of the liability they'd open themselves up to.

For balance - I've done thousands of miles with a broken ABS system (multiple sensor and hub faults over my ownership, each one I did resolve).

Strange, I seem to remember, when I worked for MG Rover building the front and rear suspension units for first the 200/400 then 25/45/ZR/ZT, that the brakes (pre ABS) were set up on a 70/30 bias towards the front.

Also when the ABS systems were introduced we had to sit through an interminable video presentation, which I'm pretty sure stated that in the event of an ABS failure then the braking system would revert to a standard braked system.

Gloomendoom

RichardD1970 wrote: »

Also when the ABS systems were introduced we had to sit through an interminable video presentation, which I'm pretty sure stated that in the event of an ABS failure then the braking system would revert to a standard braked system.

Speaking from experience of driving several cars with failed ABS systems, they do.

Norman_Castle

For the OP

https://www.gov.uk/getting-an-mot/after-the-test

Driving a vehicle that’s failed

You can take your vehicle away if your MOT certificate is still valid.

Norman_Castle

bill_the_bus wrote: »

Car had [Has] until 27th November on MOT

gilberto wrote: »

Please can someone explain to me and the OP how their old MOT is still valid if it has expired and the new on is a fail?

Old mot hasn't expired.

Ebe_Scrooge

gilberto wrote: »

Please can someone explain to me and the OP how their old MOT is still valid if it has expired and the new on is a fail? Driving with no valid MOT surely means a fine and invalid insurance?

It hasn't expired - OP said it's valid until 27th November, so he can legally drive it until then. The fact that the "new" MOT was a failure is irrelevant, the old one is still valid.


Of course, the usual caveat that you can be done at any time for driving an "unroadworthy" car, whatever the MOT status, always applies. But in terms of the pure "driving without a valid MOT" offence, OP is in the clear.

Ebe_Scrooge

bill_the_bus wrote: »

... as its otherwise, apart from small bodywork problems, in 1st class condition.

As per all the good advice above, for starters your current MOT is still valid.


Secondly, get some other quotes for the repair, as has already been suggested.


Look at it this way - if your car is in otherwise good nick, then even if you spent, let's say, £1000 on repairs, you're left with a good car that should continue to give years of service. If you bought a replacement car, what sort of a banger would you expect to be able to get for £1000 ? With the added uncertainty that you don't know its history, and you don't really know what expensive repairs lie just around the corner.


Of course, if your car had a multitude of other problems, and you had good reason to suspect that major faults were imminent then it's a different argument. But you know the history of your car, you know how it's been looked after, and you say it's in good condition. It's a no-brainer really

securityguy

BeenThroughItAll wrote: »

What on earth are you dribbling on about? Brakes aren't 'set up' to lock at any point. Wheels lock up when available grip runs out, which is utterly and completely independent of any brake 'setup'. It's dependent on road surface, weather conditions, and the tyres.

Even before ABS, cars had proportioning valves to (usually) ensure that the front wheels locked before the rear. Indeed, I have a memory that construction and use regulations used to specify that; a car with locked front wheels will continue in roughly a straight line, while a car with locked rear wheels is highly likely to spin. Some cars (for example, Hydropnematic citroens and some commercial vehicles) actually had a load-sensitive valve on the rear axle/half-shafts to sense how much weight was in the back of the car: if you drove a BX solo for long enough the rear callipers were prone to seize through lack of use. In motorsport formulae where ABS is banned, like most open-wheel series, the brake balance control is a vital part of the drivers' armoury, and the front/rear issue is why on road cars dual-circuit brakes are split diagonally, not across axle.

To see concrete evidence of this, note that standard brake setups over the years have included disc front drum rear, ventilated multi-piston front and simple discs at the back, massive leading shoe drums at the front and standard drums at the back. Similarly, large motorbikes usually have dual discs with multiple pistons at the front, with either a drum or a small disc at the back.

securityguy

gilberto wrote: »

Please can someone explain to me and the OP how their old MOT is still valid if it has expired and the new on is a fail? Driving with no valid MOT surely means a fine and invalid insurance?

Invalid MoT doesn't invalidate insurance, as has been discussed repeatedly.

In this case, the MoT hasn't expired.

There is a mechanism, which I don't think anyone has mentioned, for MoT testers to issue a red prohibition notice on dangerous cars, making it illegal to move them other than for repairs. There's no mention that this has happened.

marlot

Norman_Castle wrote: »

Old mot hasn't expired.

Even if it hadn't. driving without an MOT certificate is a relatively minor offence (fine, no points).

Driving an unroadworthy car is a much more serious matter. But if the OP had been driving for a while with the ABS light on, he's not committing any further offence just because he's failed an MOT.

onomatopoeia99

securityguy wrote: »

There is a mechanism, which I don't think anyone has mentioned, for MoT testers to issue a red prohibition notice on dangerous cars, making it illegal to move them other than for repairs. There's no mention that this has happened.

I have always wondered about this, an MOT tester told me that only VOSA (as they were called then, no idea of the current name) could prohibit a car from being used, not him.

I don't know the specific legislation so don't know who is right. Would be interested to find out though.