Are there any ‘must’ mods for used imports?

There is no “stock” modification you must make to ensure a car specified for use in cool and smooth conditions will run properly and trouble-free in a hotter, rougher, dustier place. It depends on the make, the model, the individual vehicle, and your intended use (around town or long-distance highways or rough tracks; heavily laden or nearly empty; fast or slow?). And not least on the mechanical know-how at your disposal. 

What you need to appreciate is that there are differences in specification, and some of them can be significant. Some are simple to adjust, with little risk. Others are complex and can have severe side effects. 

For example, domestic models for non-tropical markets may have smaller radiators or softer springs and dampers. This does not mean the car will immediately overheat or that all its legs will snap and fall off; but the car will be less able to cope with extremely hot or rough conditions, have less margin of tolerance for neglect or defects, and be more prone to premature failure. 

Softy-softy specs of used cars originating from markets with smooth conditions may be found all over the vehicle – in engine and body mountings, exhaust brackets, spring and control arm bushes, etc. Changing some of these components and not others can produce some negative side-effects. Manufacturers are careful to “balance” every element of the suspension system all the way from the tyres to the driver’s seat (and everything in between); and when they fit heavy duty suspension specs they often also reinforce parts of the frame and body-welding to match. 

Mix-not-match issues can arise all over the place, whatever modification you try to make (eg to ground clearance by fitting spacers, or changing wheel sizes or tyre profiles) so mods to avoid one problem can often cause another unless you (and/or your mechanic) are tech savvy. 

There are one-off quirks on particular parts of particular models, but the foregoing gives you some broad principles on which to decide whether your newly-arrived used car should just be given a thorough service and wash (to get rid of the sea salt etc), or whether it should spend its first few Kenyan days (rather than the rest of its life) in a workshop. 

As ever, prevention is better than cure, so picking sources and makes and models with proven track records in this market is the rational starting place. 

Brakes that need to be pressed more than once

When motoring on smooth roads my brakes work normally. But after some distance on bumpy dirt roads, the first press of the brake pedal is soft and not effective. I have to pump the pedal two or three times, then the brakes work well. What is wrong? There is no loss or leak of brake fluid. - Andrew 

Short answer: At the risk of sounding a bit preachy, the main thing that is “wrong” is that your brakes are now dangerous. Don’t tolerate the problem any longer than you have to. Get it fixed. 

Even though multiple presses make your brakes work, and may continue to do so for many further trips, do not delay remedy until your next regular service. Get the car to a garage as soon as you can. 

Although three quick presses will probably continue to give you functional brakes in normal motoring circumstances, that small delay could make a life-or-death difference in an emergency. If a child runs across the road in front of you, your reaction time will be increased by at least one second, even if you have feet as fast as a ballet dancer.

At 80 kph, in that time your car will travel more than 20 metres before the brakes even start to work. That one second, and that 20 metres, is in addition to “awareness” time, “thinking” time, “decision” time, “remembering” that you have to press thrice time, “physical movement” of your right foot time, and the “distance” the car will travel both before and after braking before it slows to a non-lethal speed. 

A “soft” pedal at first press is most often caused by contamination of the brake fluid with dirt, or water (which becomes steam at brake temperatures) or air (which compresses too easily and undermines hydraulic pressure which is essential to effective braking). 

Longer answer: You have already checked the brake fluid level. But was the fluid as clear as clean water? If not, then completely flush the system and replace the fluid with brand new, from a sealed container within its best-by date. Whether or not you need to replace the fluid, ensure the system is fully bled of any air, that pedal pressure is correct at first press, and that there are no leaks from any part of it. 

As part of that process, check the level of wear on the brake pads, that the calipers are properly set, that the discs are in good condition, that the pistons which press the pads against the disc are not worn or rusty or jamming/sticking, and – because this is also a likely cause of your problem – the mechanism that releases the brakes when you take your foot off the pedal is working correctly. 

When the brakes are “off”, the pads should not be touching the disc (that will create wear and unnecessary heat) but they should be very close to it; like 1 mm. When you press the brake pedal, it is hydraulic pressure (amplified by the servo) that presses the pads against the disc, but when you release the pedal there has to be a mechanism (eg springs) to make the pad “let go”…by exactly the right amount. The fact your brakes work normally on smooth roads but change when you drive on a bumpy surface indicates that something moves out of position when it is shaken. The smooth, complete and precise movement of the pressure piston is a prime suspect. 

What makes this engine ‘judder’? 

My old diesel engine works well in low gears at all rev levels, but starts to “judder” at medium revs in high gears. Changing down immediately restores steady power. Also, if I press on through the juddering until revs are higher in high gears, power is also even. What’s   the problem? - Samuel

It sounds as though your engine is “hunting” – the flow of fuel is not always keeping pace with the ever-changing loads on the engine as you motor along at varying speeds, revs and gears. My guess is that the “judder” is most acute when you are climbing a gentle hill at cruising speed – not steeply enough to warrant a change-down, but enough to require a harder press on the accelerator to maintain speed. The juddering is probably much milder or does not happen at all when going downhill.  

The cause is most likely a defect of some sort in the fuel flow rate. Possible culprits include restriction caused by dirt in the fuel supply line or injectors, or a partial airlock, or a clogged fuel filter, or a weak fuel/injector pump.

The problem is not constant possibly because at high engine revs the pump is operating vigorously enough to overcome the restriction. At low revs demand for fuel is much reduced and enough is getting through despite the restriction or pump weakness. But in the middle – what you call “medium revs in higher gears” - the pump is running more slowly, not enough to overcome the restriction, but fuel demand (especially on a climb) is high enough to cause a fuel supply deficit. So you engine is “hunting” for more fuel; it “judders”.

The remedy is a step-by-step check and service of the fuel supply system, from the tank and pre-filters through the pipes to the main filter, the low and high pressure pumps, and the injectors.

More tricks-of-the-trade? 

I have tested your tip on using fly spray to remove stubborn glue residue from windscreen stickers. It works! Do you have any other homespun remedies to share? - Raphael 

Here are three off-the-cuff suggestions (and if readers would like to share their own tricks-of-the-trade then I would be glad to pass them on).

One: If your hands get really grimy after working on an oily-greasy part of the car, try “pre-wash” them with a squirt of WD40, then use a grab of clothes-washing powder, it works better than dish-washing liquid or a bar of soap. Use very little water and lots of rubbing to start with, then increase the dilution as you rinse.

Two: A couple of drops of brake fluid can be helpful in loosening a rusty nut. Mind the paintwork, though; it doesn’t like brake fluid. 

Three: The gentlest rubbing compound that might help get grime off a headlight lens without scratching the glass (or plastic) is…toothpaste.