Archive for the ‘mot failure’ Tag

Dangerous to drive

It is not often that I feel the need to highlight something on the VT30 failure notice as being dangerous to drive, just recently I have had to use it for brakes and suspension faults. The first case being a pair of rear  leaf springs on a Ford Transit which had fractured at the anchor end spring eye, the only thing holding the spring in place being the weight of the vehicle bearing on the spring eye.


The spring can clearly be seen, from the rust “witness marks” to have worn away at the anchor bracket where it has been moving sideways.

leafspringAnother pair of items to crop up under the dangerous to drive tag was a a pair of front brake hoses on a Ford Maverick these had deteriorated so badly that the braided innards of the hoses were clearly visible













Earlier in the day a customer had brought us a Mercedes ML320 with a pad warning light on, and asked us to replace the front brake pads as he’d done the rears, or friend had, to save some cash.  Once we’d removed the wheels to replace the front pads we knew they were not the reason for the warning light being illuminated, so we turned to the rears to check the wear sensor wire, immediately noticeable was  the thread of a brake caliper bolt and therefore the lower end of the caliper was not secured and had broken the sensor wire, thus causing the light to come on.


Had this been the upper caliper bolt it is quite possible that if the caliper had been caught by the wheel rim it would have caused serious damage to the wheel, the caliper and the caliper bracket, with the wheel quite possibly locking up .


Incidents like these are rare but unfortunately they do happen, which is why we have Mot’s, no matter how a good a mechanic you are, or think you are, another pair of eyes checking the work afterwards can be an extra safeguard for vehicles on our busy roads.


Dangerous tyres once again.

I’m often amazed at the lack of awareness of some drivers.  A Peugeot 307  brought in for mot had an obviously noisy exhaust blow,  the vehicle presenter was surprised when the boss said it was unlikely to pass the test with it blowing as it was.  However we  proceeded to carry out the Mot, before it had even been logged onto the system it was obviously going to be one of those vehicles, just a quick glance before getting into the drivers seat and it was labelled as dangerous to drive.
delaminated-tyre It started poorly and then went from bad to worse, as a glance at the 2 page vt30 shows

The front suspension arm bushes very badly worn and knocking, a rear brake binding, front brakes pulling severely to the right (into the path of oncoming traffic). Never before have I had to issue a VT30 with more than a couple of “dangerous to drive”   items.  Just manoeuvring the vehicle on our forecourt was enough to frighten me, clunking from the suspension, dragging from a rear wheel and then seeing the presence of a child seat in the car was a little worrying too.

Bushes, suspension and steering

Rubber bushes are used nowadays on the majority of vehicles to isolate and dampen road noise whilst at the same time allowing suspension and steering components some flexibility and movement.

Problems begin when the bushes deteriorate or become unbonded, when this happens the suspension component is no longer retained in its correct position, excessive movement occurs and noise increases.

The above are all examples from the front suspension, the rear suspension can also have rubber bushes and mountings, again when the bush deteriorates excessive movement and noise occurs. Laguna-rear- subframe

The above image is that of a Laguna rear arm mounting bush.

Also subject to checking for excessive movement  are the rubber bushes that steering racks can be mounted with, again the criteria when being checked is is there excessive movement or is the component insecure. The image below is of a pair of new steering rack mounting bushes beside a pair of worn bushes, two pairs are needed to mount the rack in this case a 54 reg mercedes c class.c-class_steering

In the above case the steering rack was moving enough to cause the ESP light to illuminate and for the ECU to limit the power produced by the engine.

Since the 20th of this month the ESP light being illuminated is a reason for rejection (failure)

Brake pipes and hoses

A slide show of various brake pipes and hoses found on vehicles for test, in the  case of the leaking brake pipes,  the fiesta rear began leaking on test and the other (astra o/s) fractured and leaked as it was prised out of its support clip prior to repair.

Seat belts.

Had a nice old 1954 Bentley in for Mot today, has been kept up together. The owner has had inertia reel seatbelts fitted into the front of the vehicle. The driver’s seatbelt appears to have  been extended, but dangerously by using a friction buckle set up.A vehicle of this age does not have to have seatbelts fitted, see however as the belt  was fitted it had to be checked and had to conform to MOT standards, .

If he’d removed the seatbelt before the test I’d have been none the wiser and he could have gone away with a pass.

A stately old lady

Once again I’ve had an uncommon vehicle to test , this time an Alvis TA21, despite her weight of 1500 approx kg, if she lifted her skirts she could do 100mph.

All was going well until she had to have her brakes tested in the roller brake tester, whilst all the efficiencies were good, unfortunately owing to lack of regular use she suffered from front brakes badly imbalanced. 71% imbalance is the highest I believe I have ever seen, and in this case dangerous inasmuch as it pulls towards the oncoming traffic

Drivers view

Drivers view

A customer brought in a car with an opaque sunstrip on the windscreen, from the outside it didn’t look too bad although it encroached into the area swept by the wipers by more than 40mm.

The view from the inside of the car at eye level however shows how much of the driver’s view is obscured.

I’d hate to be sat in the car behind this car if he was the first in a queue at traffic lights !

More on brake failures

The following images came from a vehicle presented for test recently.

The flexible brake hose had been renewed after it’s last Mot, at that time the presenter had been advised that the brake hose was slightly deteriorated and would need replacing before the next MOT.
This was duly done by a friendly amateur mechanic the vehicle presenter knew. Unfortunately the brake hose was replaced incorrectly and slightly twisted, this lead to the covering “spring” cutting into the rubber hose and exposing the inner core, which was beginning to chafe.On the same vehicle the front brake pads were almost metal to metal on the (worn) brake discs, again leading to a MOT failure of the discs and pads.
If the vehicle had had even basic maintenance checks carried out in the previous 6 months by a competent mechanic both of these faults would have been spotted and rectified at a time the owner would have had more funds rather than just after christmas when we’re all short of cash.

Pitted Brake Discs

This last week I’ve had a couple of vehicles in with a  brake disc severely pitted, the first being a Peugeot 406 with one of the rear brake discs being severely pitted, this lead to a couple of reasons for failure, one being the severe pitting but it also caused the brake application to be  uneven, although we do not talk about rear brake balance, the mismatch between one side and the other was in the region of 60%.

Initial thoughts on the cause of the problem suggested perhaps the caliper on the pitted side was not functioning efficiently or sticking, however once the pads were removed a thorough check revealed no stiffness or stickiness in operation. Once new discs and pads were fitted the brake operation was checked and the mismatch was down at 5%. Perhaps the vehicle had not been used for a while and the disc on that side of the car had been more exposed to the weather somehow.

Certainly  the Fiat Seicento the following brake disc came from had been laid up for a while (6 mths), the original problem to cause the lay up had been a wheel stud in the drive flange loosening off and causing severe brake judder.

On test the pitted disc had severe judder  and caused severe imbalance in the region of 45%,  this was also dangerous to drive particularly as it was on the drivers side of the car, pulling towards oncoming traffic.

Replacing the discs, pads, the damaged drive flange and studs was necessary.Slight surface rusting of brake discs isn’t normally a reason to fail unless it causes judder or imbalance, however the above examples are extreme and a fail was justified on the amount of pitting alone.

205 axle movement

An example of excessive wear in the rear axle of a Peugeot 205 recently presented for an Mot, usually found on some of the “go faster” 205s this  was found on a small 1000cc model. With the “go faster” models the wear is usually immediately apparent by signs of the rear tyre rubbing on the inside of the rear wheel arch. However in this case with the vehicle having 145 x 13 tyres the play only showed up by rocking and shaking  the rear suspension. Whilst the video doesn’t show the amount of movement very well the audible clunk is quite apparent The tyres fitted to the rear axle were quite new, so no unusual wear was apparent.

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