Archive for the ‘corrosion’ Category

Some more on corrosion

This week we have had a Wreg Ford Ka, not a bad example of it’s species, no real problems except for some corrosion to the seat mounting area.

The underseal had cracked around the seat mount, asking my assistant in the car to move around on the seat revealed flexing of the floor at this point, removing a thumbnail flake of underseal revealed a small pinhole in the floor.

When carrying out the repair however, what appeared to be a small repair became a lot worse as removing the seat and carpet in the area revealed a large area of fibreglass smoothed to look like seam sealer and painted to match the rest of the floor.

The extent of the repair needed

I previously mot’d the vehicle last year and only mechanical problems were found, I obviously missed the fibreglass underneath the seat mount and carpet, and no problems were visible in this area when checking the underside from underneath the vehicle. we haven’t seen this vehicle except for these 2 mots but the owner is not mechanically minded so unlikely to have made this fibreglass repair. The previous owner had sold it on with 3 mths left on the mot, for the time and artistic effort involved, at that stage it would probably have been cheaper to have it welded up properly.


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.

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.

Say no to 4-2-2

The current government are still considering a change to the mot scheme by extending the period between mot tests, even though the previous government decided against it after examining the options.

Should this happen we could find vehicles in a dangerous condition for a further 12 months compared to now.

Some examples.

A tyre badly worn through to the cords,
The following example of corrosion found on a Subaru Justy had an advisory notice issued 12 months ago, regarding the corrosion now bad enough to fail.

The pale blue you see in the centre of the image above  is the inside of the chassis above the rear subframe mount, heavy braking could well have caused the subframe to break away causing serious loss of control. I was unable to complete the test and abandoned the test as I could not complete a brake efficiency test.

On to  another vehicle, approx 3 months ago an advisory notice was issued with regard to the rear brake pads wearing thin. Returned to us this last week to have the brake pads replaced.
As you can see from the above image one of the pads has had the metal backing worn to half of it’s original thickness, it must have been grinding away warning the driver of the problem for at least 500 miles.

It seems that the advisory notice is totally ignored, the necessary repairs aren’t done because of cost constraints, but how much more expensive is replacing the car after an accident, or even a fatality?

Many drivers seem to be of the opinion that as the vehicle has passed it’s MOT it is good for another 12 mths without any maintenance.

The MOT is only a check that certain components met a minimum laid down standard at the time of the test 

If 4-2-2 testing becomes a reality we could see a lot more vehicles in this condition on the road.

Sign the  petition at and voice your opposition to the proposed change.

Suspension and prescribed areas

A number of items have cropped up this last week, a broken coil spring seems to be a regular occurrence, this one seen on a Renault Clio
In it’s normal position, rather than wheels free, the break was hardly noticeable, however once jacked up it was immediately spotted.

Following on from springs another regular occurrence are suspension arm bushes, the following images are from a ‘Y’ reg Honda Civic.
Again on initial viewing of it, it didn’t appear too bad, however on inspection of the underside of the arm it was clear that the bonding on the bush had failed allowing excessive movement, as the arm moved up and thus contacting the front subframe, leading to a heavy knocking over bumps. The same vehicle also had a problem with 2  antiroll bar links having become detached at the balljoints.Which were also making a characteristic knock over small bumps.

Then we had a Mazda MX5 suffering with some tinworm, the outer sills seem to suffer just forward of the rear wheel arches,Further inspection also revealed excessive corrosion to the sill closing panels inside the rear wheel arches, not something the owner would be expected to notice under normal circumstances.
All of the above would be spotted in good time if the vehicles were regularly serviced.

deterioration over time

Following on from the last post here’s an example of how rapid deterioration can occur.

I’ve been testing this vehicle for 3 years or more, other than minor items never anything to worry about.

This year however was different as the rear chassis had cracked on both sides,

The owner had noticed the problem after he’d had the vehicle steam cleaned prior to coming for the Mot and had mentioned it before I put it on the ramp.

The reason he’d had it steam cleaned was because he had had a fuel leak develop,
add in some lighting problems and not a good day for him.

Prescribed areas

Corrosion and prescribed areas.

The Mot Tester’s manual,appendix C describes a prescribed  area.

“Certain areas of the vehicle structure are particularly important for the safety of a vehicle. Particular attention must be paid to these areas during an inspection.

These areas are:
· The load bearing parts of the vehicle to which thetestable items defined in Sections 2, 3 and 5 of the Inspection Manual are mounted, and
any load bearing or supporting structure or supporting panelling within 30cm of the mounting location.”

Sections 2,3 and 5  refer to steering and suspension, brakes and seatbelts.

Excessive corrosion is described as

· The corrosion has caused a hole in the metal, or

· it is weakened to the extent that by finger and thumb pressure it does not feel sound, or
· finger and thumb pressure or use of the  Corrosion Assessment Tool causes a hole.

Some corrosion may actually fall into 2 different categories such as this sill on a Nissan Micra, the corrosion falls within the seat belt mounting area and the rear suspension mounting area.rusted outer sill

Therefore on the vt30 failure notice the same corrosion will be referenced as 2 reasons for rejection, seatbelts and suspension although only one repair is actually needed.

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