Tech Talk: Caravan Clinic

Cool responses
Judging by the number of letters received, Fred Waller (‘Fridge woes’, May 2005) isn’t alone when it comes to poor refrigerator operation. Colin Mortimer cited the case of his van that he bought in 2001.

When he turned on the fridge in preparation for his first trip, it wouldn’t operate, and the replacement of a faulty element meant departure was a day late.

In 2004 the thermostat was damaged by the drip tray moving about. After spending $280 on repairs, Colin was informed by the service agent that the problem had been caused by a manufacturing fault. When he wrote to the manufacturer, Colin received a reply which, in part, said: “We cannot accept your claim that the product had an inherent fault… our products are subject to rigorous quality control procedures prior to dispatch from our factory.”

Like others who have contacted us over the years, Colin feels that caravanners sometimes do not get value for money when it comes to appliance warranty. He says that his 1964 fridge in the shed and the 1982 one in the kitchen have never missed a beat. Yet the one in the van failed after only 31 weeks of use. Regardless of why it failed, Colin says that, like Fred Waller’s fridge, it should not have done.

After all, refrigeration is not new technology.

I sympathise with Colin and others in a similar situation. Warranty responsibilities and rights are not always understood by consumers and retailers.

The ACCC puts out a useful brochure, titled Warranties and Refunds, which deals broadly with what consumers and businesses need to know about basic warranty and obligations. It should be available from most State consumer organisations or by visiting the web at www.accc.gov.au – type ‘warranties’ in the search box.

It may have helped Colin if the service agent had given him a report, stating the basis for the opinion that it was a manufacturing fault. Statutory or implied warranties cover situations where faulty workmanship or materials are evident. These are not to be confused with manufacturers’ voluntary warranties that often set a time limit.

On a related topic, Peter Byrne added to Geoff Nicholls’ experiences (‘Cooling the fridge’, June 2005). At one stage Peter discovered his seven-pin trailer plug and socket had welded together, due to excessive current flow while operating the fridge during travel.

After he installed a 50 amp two-pin Anderson plug and ran large diameter cables from the car battery to the fridge, everything worked fine. Peter’s experiences proved once again that you cannot expect a caravan refrigerator to work efficiently on 12V if it isn’t getting the supply it needs.

They have found their Magna to be an excellent tow vehicle with good fuel consumption figures. Bruce was however concerned about the somewhat soft rear suspension and fitted a pair of King progressive rate coil springs after discussions with his local Mitsubishi dealer. He says that for $200 the car has been transformed and is even better than before.

As we have said many times, there are instances where different springs are justified, as long as they are not used in place of a weight-distributing hitch.

Easing the load
Q During a recent visit to New Zealand I saw a caravan with pivoting, castor-type wheels between the towbar of the car and the coupling on the caravan.

I remember similar setups in Australia many years ago. They seem like a good idea, as they would take weight off the rear of the car and prevent bouncing on undulating roads.

Are these available in Australia? Are they legal? Would you recommend their use?
An article on page 19 of the March/April issue of Restored Cars magazine shows two examples of these wheels.
Ron Traill
Email

A The equipment that you refer to is generally known as a ‘dolly’.

As you suggest, these keep excessive weight off the back of the tow vehicle and do away with the need for a weight-distribution hitch.

While the principle is quite sound, there is a problem when it comes to travelling at higher speeds, the latter in part due to the smaller wheels. You’d have noticed that both pictures show very large caravans. As far as I know, these dolly setups haven’t been available in Australia for a long time.

Internet letters from caravanners have said that they have increased the towball weight by fitting stronger springs. Is this acceptable?

Other caravanners have told us that the onus is on the insurance company to prove that the towbar weight was excessive and that we should not worry about meeting these criteria as long as the van tows easily and correctly. Hope you can help.
Peter Holland
Email

A We are certainly willing to help but you probably won’t like the suggestions. Unfortunately there are many caravanners who are happy to offer advice, although they have no real knowledge of what is involved. Comments on Internet websites would have to rate among the worst.

The Nissan Terrano is a nice car but hasn’t all the attributes that make a good tow vehicle. At best it may be suitable to tow 1500kg but then the 100kg ball load allowance puts this out of the reckoning. Nissan’s 100kg figure most likely indicates that the company is concerned about the integrity of the rear of the vehicle.

Boosting spring strength is not going to help as the towbar has been designed and manufactured to comply with the vehicle manufacturer’s requirements.

Caravanning is a great lifestyle, as many continue to prove. However, you need to invest in the right equipment if you want to enjoy safe and reliable journeys.

Also, the car and trailer have to be compatible, with the trailer loaded so that about 10 per cent of the total load is on the tow ball and the correct towing equipment is needed to keep the outfit stable.

You might find a small and light rear entry pop-top that will fit the Terrano’s specs, but the internal space may be a little limiting for long-term occupancy.

The bottom line is that if you want to tow a 4.8m pop-top safely and legally then the Terrano is not the car to use.

As far as insurance is concerned, when you signed the proposal you did so with the knowledge that you would at all times operate the vehicle within the vehicle manufacturer’s recommendations and current road rules. Like all of us, you no doubt read the small print.

Aerodynamic debate
Q I noticed in recent editions of CW a debate regarding the use of air deflectors. While I am not an expert in aerodynamics, I do know that in the 40 years I have worked in the aviation industry, I have never seen an aircraft with a flat rear end.

From schoolboy physics I remember that the shape with the least drag has a semi-spherical front faired into a cone with a point at the rear – a bit like a wing section, where the rear is sharper than the front.

My conclusion is that as long as caravans continue to be made with flat backs we will be stuck with excessive drag. Any amount of modification to get the air to flow smoothly over the van will have minimal impact on the fuel consumption. Practically speaking, of course, a pointy rear could result in an odd-shaped bed.

I recall an American van made from aluminium that had a curved front and rear and was reputed to be the most efficient. I would like to see a discussion on driving techniques and ways of reducing fuel consumption.
Alan Swann
Lower Plenty, Vic

A Alan, you have raised many interesting issues. Aerodynamics is a very complex science – what is beneficial at high speeds may not necessarily make a difference at low speeds.

You are right: the rear shape can be as important as that at the front. While a pointy rear may be the ultimate, it has been proven that chopping the point back doesn’t make a big difference to vehicles driven at moderate speeds.

It may sound unkind, but aerodynamics experts and enthusiasts would probably refer to caravans as “square boxes”. The exception is probably the American Airstream RV, to which you referred. If you could guarantee always to tow without the wind striking the rig from the side, a well designed and positioned wind deflector can make a difference.

Ultimately it comes down to manufacturing costs. A caravan, being mobile accommodation, must first be functional.

Second, the manufacturing cost needs to be such that the end result is affordable. Basically, an object with square corners is cheaper to make than one with round corners. Having said that, it is interesting to note that replacing square corners with ones that have a 150mm radius can reduce drag by about 10 per cent.

Keep reading CW, as in the not-too-distant future we’ll have something on fuel economy. And a story on this topic would have to include something on aerodynamics. The challenge is to do it in a way that is meaningful to our readers.

I have heard conflicting reports about placing jerry cans in the boot of a van. I am new to caravanning; please advise me of the best options, so I can start on the right foot.
Mike Blewet
Cranbourne, Vic

A Before considering the type and location of the container, first ask “Is it necessary to carry additional fuel?”. Unless travelling through remote areas, most cars are able to carry enough fuel to go from one supply to the next.

Some people carry spare fuel that they use if prices are too high in certain places.

Personally I’d rather pay a few extra cents per litre than carry fuel. Apart from storage problems, there are certain dangers associated with carrying fuel. These include damage to the container by stones or other objects; possible leaks; expansion in hot weather; consequences of being involved in an accident and simply pouring it into the vehicle’s tank – not to mention static electricity.

If all this sounds a bit over the top, it is because the carrying of fuel is not like carrying water. You need to be aware of the precautions to take.

The construction of fuel containers is covered by Australian Standard AS/NZS 2906.2001: Fuel Containers – Portable Plastic and Metal. As long as the container used meets the requirements of this, either type will do. It often comes down to personal preferences.

Some will say that plastic containers crack (which may have occurred in the days before the standards), while others will mention the corrosion on the inside of metal containers that can cause foreign particles to enter the car’s fuel system.

Irrespective of where the containers are located, they need to be protected. Within the confines of the body is preferred; an example is the side of some camper trailers.

You could use the front boot as long as, like the LPG cylinders, they are secured. Of course, if there are batteries in the boot than you can quickly forget this idea!

If I owned a 4WD and my travels demanded that I carry additional fuel, I’d consider an auxiliary tank, or a larger tank, depending on the vehicle. I could then always take advantage of cheaper prices.

Australian Standards can be found by visiting the web at  www.standards.org.au

We hope to pick it up in Melbourne during Aug/Sept. Presently we are getting 10L/100km and wonder what increase we can expect when towing.

With petrol prices over $1.35 per litre on the Nullarbor, it may be an option to get petrol from all stations to spread the costs, as was suggested in CW May, # 417.
Chris Wright
Waikiki, WA

A A friend has been towing a 1400kg van with an X-Trail and reports that it is an excellent combination. He normally tows at about 90km/h in Third with the X-Trail returning between 12-13L/100km.

He suggests that for towing, select 4WD in the ‘automatic’ mode rather than AWD. This allows the front wheels to provide the drive under normal conditions and give best economy. When accelerating on a slippery surface, drive forces will be apportioned to the rear wheels. When driving solo on sandy or muddy surfaces, AWD is best.

On the assumption that you are collecting the van from the factory, make sure that you have a complete and thorough pre-delivery service carried out on the van by an experienced service department, prior to departure from Melbourne. Also allow time to stay in a local park for a few days to make sure everything works.

I sometimes feel that people worry too much about fuel prices. Let’s assume that you took the scenic route from Perth to Melbourne and covered 4000km. If the consumption was 10L/100km you’d use about 400 litres of fuel.

At an average price of $1.10/litre it would cost $440. At $1.20 it would be $480. Is that extra $40 worth worrying about, so you can save a few cents per litre?

It has leaf springs and beam axle and is fitted with 195R14 light truck tyres. We have tried pressures from 250-320kPa (36-46psi) but the van does not tow well.

Except for smooth road surfaces, it tends to bounce side to side and is affected by crosswinds or passing trucks. I use a Mini Hitch. Car tyres are inflated to 240kPa (28psi). Any uggestions for me?
Les Woods
Maryborough, Qld

A Your problem has all the symptoms of either a poorly balanced van or one with very stiff suspension and hard tyres.

Based on your description I’d leave no stone unturned to find the cause as, in its current state, it sounds a bit unsafe. The suitability of the Commodore and the van is obviously not in question.

This is a situation where it is necessary to go back to basics. Start by loading the van and visiting a weighbridge. Try the local council or a transport company – I’m sure there’ll be one in Maryborough.

Weigh the van on and off the car to determine the total weight and the ball load. The latter is the difference between the two weights.

Being a rear kitchen van, I’d be looking for a ball load of about 140kg or more. If the wheels are located near the centre of the body, this may be difficult to achieve by adjusting the contents. If the spare wheel is at the rear you could put this on the A-frame.

If all this checks out, measure the length, width and thickness of the spring leaves and count the number of leaves on each side. Armed with this information you should be able to find out the strength of the springs from a spring manufacturer. Try the Brisbane Yellow Pages.

The capacity should be in the vicinity of 1500kg for the two. If it is much greater than this it may be necessary to remove a leaf to improve the ride quality. Based on a total load of about 1400kg, 320kPa (40psi) should be right for the van tyres. I’d put the same amount in the car’s rear tyres and about 250kPa (35psi) in the front ones.

If you’re heading south call in to the Caravan Repair Centre at Caloundra and have a chat to Merv Flynn. Merv has many years of caravanning experience and can inspect the van to isolate the cause. Merv’s contact number is (07) 5491 2560.

Also, we need to charge the caravan battery when away from 240V power. Would a generator or solar panels be best? We only want to use 12V lights and a water pump.
Paul Bahyl
Ridgehaven, SA

A As long as the Supreme’s ball load is less than 225kg, the Challenger will do a great job. Vehicles with bigger engines may have a bit more get-up-and-go, but not be as fuel-efficient as the Challenger. You will need to use a weight-distribution hitch to provide for safe towing.

A generator might upset the neighbours. Seriously though, using a generator to charge a battery seems overkill.

Solar panels can supply charge while travelling or sitting on site. Neither option, however, is cheap, particularly if all you want to do is operate a couple of lights. If a solar panel has appeal then a portable one that you can put in the sun may be the way to go.

Alternatively leave out the battery and go for a power pack or portable 12V supply. These can be charged from the car while on the move, or a small battery charger when 240V is available. A power pack also doubles as a booster battery that can start the engine when the standard battery is flat.

Chat to Garry at the Home of 12V on (08) 8536 2144 or Jeff at Campsite Products on (08) 8384 6588.

A As long as the work is done by a qualified person, relocating the springs above the axle is quite acceptable. It will increase the ground clearance about 100mm, being the thickness of the axle and the leaf spring.

If it was only 40mm you wouldn’t bother. It shouldn’t affect the way the van tows but you will have to adjust the ball mount to accommodate the higher coupling.

As the axle normally has spring-locating plates welded to it (or should have) it is necessary to either weld on new plates or turn the axle upside down.

In the case of the latter the brake assemblies will then have be unbolted and rotated 180 degrees so they are back in their original position. You may also need to relocate the park brake cable.

Otherwise, remove the complete suspension system, including the spring mountings, and weld a piece of 100mm x 50mm rectangular tube to the bottom of the existing chassis. The suspension is then re-attached. This method requires careful installation to ensure that all four wheels remain parallel to each other.