Archive for the ‘failure’ Category

Airbag lights

Since 20th march the airbag/srs light indicating a fault is a reason for rejection, however if the light doesn’t illuminate it’s only an advisory item, very odd.

However we had an 02 Renault Clio in for an Mot with the airbag light lit up. The presenter a little bit peeved when told it is a fail as it has been like it for the last 2 mots and never been a problem before.

I think he was visualising a huge bill for airbag replacement, we’ve all heard stories of figures of £500+ for an airbag being replaced. However such a bill wasn’t necessary, once the diagnostic scanner was connected the fault was identified as being the drivers side sensor short circuited. When peering under the drivers seat it was noted the carpet was wet, once the sensor was located and looked at with a light there was an obvious rust stain on the side of the sensor.

A replacement sensor had to be ordered from france, took about a week but it only cost approx £31 plus diagnostic and fitting to put the airbag light out. A lot better than £500.


Old sensor removed from it’s original location attached to the sill.

The cause of the wet floor was established as the sunroof drain tubes blocked, these were blown through to clear them, a wet vac and valet recommended to dry out the floor mats, and to keep a check on the wetness of the floor mats and to return if dampness builds up again


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.

Suspension Components

A number of suspension component failures have cropped up recently, beginning with a Nissan Micra 09 reg rear shock absorber, the wording of the Rfr is “serious fluid leak”. As can be seen in the image the dirt and dust on the whole shock absorber body and lower bush area has a damp wet look whilst the other components in the vicinity have a uniform dry dusty look to them, a sure sign the fluid is coming from the shock.

Surprisingly Nissan claim that this is fair wear and tear, so their 3 yr warranty doesn’t apply to this item. On an under 3yrs and under 24,000 ml vehicle ??

We also had a VW  Passat with a split cv boot for repair, the owner of the vehicle had looked under the vehicle and hadn’t been able to see the split, I took this image during the repair, because on these vehicles it is difficult to see the split in situ.

A customer brought in a 02 Renault Laguna complaining of a rubbing sound and smell of burning rubber, we put the vehicle on the ramp, and a quick look revealed the source of the noise and smell. The darker black ring is caused by the spring rubbing on the tyre.

A broken coil spring rubbing on the inside sidewall of the tyre and also touching the wheel rim.

The polished area of the spring is where it was rubbing on the tyre,

As a matter of course we also checked on the other side of the same axle and this revealed a crack in the base of the other coil spring, not easily seen, as the lower end of the spring is encased in a rubber sleeve, however the broken section moved easily when wiggled by hand and is slightly out of position.

A final coil spring on the rear of a Peugeot 207, 07 reg, the rubber spring seat out of position a sure sign that the lower section of coil is missing.

This weeks crop

Several items of interest this week, the first is regarding seat belts and their associated mountings.

When a seat belt is attached to the seat, then the seat mountings are checked for security and corrosion in the surrounding area.

On checking a seat on a Ford Ka it was noted that the seat seemed to move a little more than normal when rocked lightly. As the mat above the seat mount was easily lifted, then a further check was simple and disclosed the securing bolt sat beside the seat bracket.

The vehicle presenter had no idea that there was a problem. The vehicle had been regularly serviced by the main dealer and as far as she was aware the seat had never been removed.

The second item concerns standards of corrosion repairs.

A Nissan micra in for MoT had previously had a repair to the rear sill because of corrosion, looking at the repair from outside the vehicle there were signs of welding with a thin skim of body filler and paint to tidy the repair up. The repair felt sound and didn’t “give” under thumb pressure.

Inspection from underneath revealed however that the bottom edge of the patch had had no weld applied at all. The testing standard for patch repairs requires that the repair should be seam welded along every edge.

The third item comes from a vehicle we had in for repair as the brakes felt spongey and was losing brake fluid. On inspection it was immediately obvious a rear brake hose was bulging, we’d had no need to apply pressure to see the problem.

The inner core ofthe hose had deteriorated and was allowing fluid to seep under the outer rubber covering, had it been on a front brake the outer covering would probably have split and caused a serious brake balance problem.

This second image shows how badly the outer covering had stretched when the fluid had seeped into it.

Illegal tyres and penalties

This week we had a vehicle in with the tyre below fitted, before commencng the test it was noticed that the tyre was underinflated and had a split in it.

A view of the tread pattern shows severe wear at both edges of the tyre usually a sign that the tyre is being run underinflated

Normally the tread covers the whole tyre width as the image below shows along with the position of wear indicator bars

Also on the vehicle was a bald rear tyre.

We’d previously had the vehicle in 3 months ago for other work and had advised the owner about the 2 tyres and that he needed to rectify the problem before they got worse.

Had he been stopped by the police for a routine check he could have been facing a fine up to £2500 and 3 points on his licence for each tyre, quite apart from the risk with his and other peoples lives he was running.
For tyre advice a number of links are below

Corroded brake discs.

I’ve made several posts regarding corroded brake discs and what is an acceptable level of corrosion.

The description of reason for rejection rgarding disc condition is worded

“a brake disc or drum in such a condition that it is seriously weakened or insecure”

The first example shown below was seen on a 2003 astra rear, in this case the surface of the disc although corroded has not penetrated into the disc so that it is likely to break or crack, the brake performance however showed a slightly different story in that the performance suffered badly enough to affect the rate of application and to cause serious judder.

The following images are from a 2004 Renault Megane Scenic brought in for repair, the customer had heard a bang as she applied the brakes.

As can be seen from the below image, the brake pad is missing, the bang heard was the brake pad “escaping” from the pad carrier.

Once the repair was started the full extent of the problem was revealed, once the disc was removed the inner face of the disc was very severely corroded, and the inner brake pad was metal to metal, or in this example metal to corrosion, it appears the friction material had broken away on the inner pad too. In the image below we’re seeing the face of the pad that should have 1.5mm of friction material, and also can be seen is the way the surface of the disc has been flaking away.

I don’t know how long the brakes have been in this condition but I would have expected a grinding noise to be noticeable for a while beforehand.

Coil springs again.

Even vehicles designed for off road use are not immune to the problem of broken coil springs, such as this one found on a Landrover. This particular vehicle doesn’t get much in the way of off road use, the occasional trip across a muddy caravan/camping site, but nothing in the way of serious off road use.

A follow on from my post regarding classic vehicles becoming exempt from Mot tests, it’s understandable when vehicles like this consul come in for test. The owner has owned it since the 1970’s when it was his engineering college project.

As such it gets very little road use and plenty of care and attention before venturing onto the road.
The underside was as immaculate as this engine bay

It’s always a pleasure to test vehicles like these and to chat to the owners and learn some of the history of the vehicle.

Witness marks

Often when conducting an mot I notice something before I begin to concentrate specifically on a set  of components.

Such an item were the presence of these polished spots on the subframe and driveshaft on a VW Polo as an indication or “witness” that something was amiss.

polished spots on driveshaft and subframe

Further investigation by looking at the driveshaft revealed that it was bent as you can see in the image above.  However the full extent of the distortion and runout is best shown in the following video.

Hearing the constant knocking from this area once in the roller brake tester made me question the hearing, common sense and sanity of the driver !

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