Questionable Driving and Sat Navs

On my travels, I have begun to notice a growing trend amongst UK drivers of cars who appear to have no idea of which way to turn at junctions, roundabouts and even sometimes on a straight road. At first I thought they must simply be very old, drunk (surely not these days?) or about to break down. Apparently not. After looking into each car in question, the new reason for this behaviour is the Sat Nav. I myself am not a huge fan of the mobile phone law which is almost no deterrent to the countless people I see using their phones while driving, sometimes even sending a text. They are (mostly) bad at driving and police spot checks are the only way they seem to get caught...a waste of police time and money. I use a Bluetooth car kit which works well, but it's still a slight distraction and sometimes I find the phone conversation suffers as I have to pay attention to the road.

Somehow even mobile phone users seem not so bad when compared with the Sat Nav "wanderers" I come across virtually every time I drive. Most aftermarket systems have to be attached to the windscreen - somewhere that's either not easy to see, or easy to reach is a change has to be made. The result is people leaning over to the centre of the screen to read or adjust their unit while still attempting to drive. Sometimes they stop altogether on the busiest of roundabouts and get annoyed if anyone lets them know they are causing congestion or a hazard, sometimes they go round a roundabout 2 or 3 times and veer off without warning. What I'm trying to get at is that back before the mid 90's maps were the only way to navigate and driving standards seemed to be much better. Ok there was less traffic back then and A roads were used more, but not that many people tried to read maps when driving simply as it was less easy to do.

The best use (in my opinion) of a Sat Nav is to check your speedo is accurate (especially for old TVRs), or at least to allow it to be re-calibrated. Using one to reach your destination is fine also, but only if you know how to use it, the software updates are current, and the software is accurate for the roads you are to travel on.

I may not be all that old, but sometimes wish the old days of navigation were still in vogue. Still, if you are like me & prefer to look in a road map, they are still as cheap as ever, and just like reading any goodbook - if you look at your route before leaving, you can get to your destination without needing to stop on the way - as it's stored in your own memory!

Ever wondered about trade "secrets" in garages? Well, some are true, some are made up, so this section may be of use to many of you. Also covered are general points to watch when working on cars - there are some nasty hazards!

MOT Centers may be looking to increase sales - instead go to your local council MOT depot where they don't do any repairs. Therefore the test will be more fair (i.e. without technician bonuses affecting the outcome of the Test). The only downside to this is that the MOT will be the full fee, but that is a minimal extra expense when considering the cost of un-needed repairs. Most larger garages (main dealers especially) have a parts related bonus for the technicians. For instance any sales of brake pads/discs, tyres, exhausts etc recommended after the technician checks a vehicle can mean extra income for that technician. This has a negative impact on customers as they are often told a repair is necessary when in fact the part may have some life left in it. I have personally seen examples where owners have had new parts un-necessarily.

Hydrofluoric Acid & Flouroelastomer, and used engine oils

Rubbers used for seals and gaskets in cars very often are made of fluoroelastomers - a very versatile and tough material for any situation where a gas/oil/fluid/air tight seal is required. However, under certain conditions, this can become hazardous as it changes into hydrofluoric acid. This occurs in temperatures of 316ºC or higher, but especially over 400ºC. Water or water vapour has to also be present for the heated seal to change into this dangerous acid, but if it occurs amputation is the only answer to prevent it spreading in the event of skin contamination.

So, those latex gloves you see worn in garages aren't just to keep the technicians' hands nice & soft, they are also to protect against this type of hazard. Wear them at all times when working on your car's mechanicals, and these will also prevent oil/grease soaking into your skin. Used engine oil is a carcinogen, and therefore another very good reason to wear gloves.

Additionally, Renault have now superceded their old flourine grease with a silicone type grease when applying to 'pencil' type ignition coils that are fitted to each spark plug (as opposed to a common coil for all plugs). This may be related to the above safety warning and could be to prevent the fluorine becoming dangerous after an engine fire.

Contact lenses and MIG/TIG/ARC welding may cause blindness
Recently has been proved to be incorrect, I originall think I read the article in the Daily Telegraph in the late 1990's. What can occur is a dryness of contact lenses due to working in a hot dry air environment, so this is probably the cause of contact lense wearers finding their lenses have started to dry on their eyes. No proved permanent damage has been proven directly due to welding (as far as I have read).

Soft metal can wear out harder metal

Believe it or not, but when a soft metal (eg an alloy) is in contact with a harder metal (eg steel), in many circumstances the hard metal will actually wear out more than the soft metal. I found this out when I overused a small compressor once, and heard the big ends starting to knock. Upon stripping down the pump I found that the alloy connecting rod was in an almost serviceable condition, but the crankshaft had 2x 3mm deep grooves worn into the bearing journal. I'll never forget that time as the cheap compressors nowadays have no changeable bearing, but instead rely on the alloy con. rod material and also the oil to provide a low friction surface against the crankshaft. Metal particles also would have played their part - especially after the wear process had begun, but I could not believe the good condition of the con. rod. I showed an engineer friend and he confirmed this strange wear by saying "of course - don't you know soft wears hard?"!!!

This may explain also why steel hinge pins wear out, yet the alloy hinges are fine - a simple pin renewal makes them work fine again.

Strange Tyre Wear Patterns

Not usual with TVRs but a small possibilty....but the rear tyres sometimes can wear in a diagonal pattern to such an extent that the tyre can have perhaps 5-6mm of tread in some places, whilst wearing down to the banding in other places. I have seen this occur on some Renaults & Peugeots, and have yet to work out exactly why this occurs. Tyres wore like this from new, wheels were perfectly balanced, shock absorbers in good condition, wheel geometry checked & correct. So far the most likely cause is tyre construction - as the problem seemed to happen on certain types of tyre. However, if anyone out there has experienced this problem it would be good to hear from you so maybe a link could be found to pinpoint the problem. Clues also lead me towards torsion bar rear suspension, as that is the type I have found it to occur on so far. Perhaps it's the way the rear axle acts with each side - they are joined by solid frame and it's possible there is a resonance over bumps which cause this "phenomenon"! Thanks in advance for any input.

Mark