Roller blind fix

We fixed a blind the other day! I always wondered if it was doable like this, and if you are careful, it can be done.

When you squeeze the button, the blind should disengage and be moveable up or down. But sometimes, with old age or abuse, this doesn't happen. The tiny pip of plastic that connects the buttons to the sliders has broken off.

If you very carefully drill a small hole, at a slight angle, you can put a small screw in there (see photos) which remakes the connection.

Ok it's not pretty, but it's cheaper than replacement parts - if you could even find them.

Musings on the 410D cooling system

The fan is on a viscous coupling. You can see the vanes in the middle. The vanes sense the temp of the air coming through the rad. As the engine works hard, the coolant temp rises, and so does the temp of the air flowing through the rad. The vanes on the fan sense this, and at a given point the fluid in the vanes expands and engages the fan, which until then had been turning freely. It is arranged this way for fuel economy - you lose a few horsepower when the fan kicks in.

The good news is that if you can feel the fan kicking in and out, then at least it's working. The viscous coupled fan doesn't last forever and many old vans have worn out fans but don't know it. In a cool country like the UK you may never notice - then you go to Europe in a heatwave and climb up the alps ... and overheat. The Merc cooling system is designed for all climates and has a lot of spare capacity.

The other issue is the state of your rad. Again, they don't last for ever, and get clogged up with road dirt, and the vanes get damaged by stones etc. The vanes on the Merc rad are quite close together, so tend to easily get clogged. I fitted a new rad last year and it was interesting to see that there was more space between the vanes on the new rad. If you have a dirty rad, then it's efficiency is reduced, and so the temperature will climb quicker, cutting in the fan. It's a positive feedback loop - and each component of the system needs to be in good condition. So inspect your rad, and have it blown out with a high pressure airline from back to front. If a lot of crud comes out, then that's good!

The way to cut down the noise is by insulation. Most classic Hymers need the dashboard sorting out after 20 odd years - it's a common thing. If you can see the windscreen move slightly in relation to the dash when the van rocks from side to side, then it needs doing. There have been plenty of articles about this. When doing this job, it pays to have the new dash well insulated - thick soundproofing on the underside, and good carpet on top. I also have an extra jacket on the inside engine cover. I did mine 2 years ago, and am very pleased with the results. I reckon my van now drives as quietly as practicably possible.

Musings on the Merc 410D suspension and springs

The Classic Hymer 6 and 700s are on the Merc 410D commercial chassis. It's a good solid platform. But in commercial use - either van or flatbed, it would be lightly loaded when empty of goods, fully loaded (up to 4.6 tons!) when full. Most of the time it would be between the two. But in a motorhome configuration, the caravan body is load, so it comes out of the factory well over half fully loaded, and by the time it is full of people and all their gear it is usually over 4 tons. As a result, in my opinion, the duty cycle of the springs, and in particular the rear springs, is higher than in general commercial use. So they wear out quicker. I have had 2 S700s over 18 years, and my last van I hammered all over the place, clocking up 350,000k on some tough tough roads in Morocco etc. I broke rear leaf springs on 2 occasions, and for most of it's later life suffered from saggy bottom. So it is my opinion now, that after 25ish years it is no surprise than on many vans, depending on use of course, end up with worn springs. So there is a fair case to be made that new springs are a decent investment - certainly on the rear. I think that a 25 yr old van on original springs and shocks is now a completely different driving experience compared with when it left the factory. The problem is that we tend to drive our vans sedately - we don't push them hard, so we don't really notice. I believe that new shocks and springs would transform any old 410 based van dramatically.

It also pays to inspect your springs carefully - you may have a broken leaf, or the U bolt retainers can be broken, plus the springs front and back are mounted to the hangers with heavy duty rubber bushes, which wear out over the years. All these things are easy fixes. I had a new single leaf custom made and fitted in Turkey a few years ago. It took 2 hours and cost £75! I replaced the bushes on my old van and was amazed at the difference.

As for air suspension - Well when I got my second van 3 years ago, I decided to go to town on it, no expense spared. Top of my list was air suspension. It's hard to find the bits nowadays - there are very few left in stock anywhere. It's not the bags, it's the metalwork that goes with them - it's quite a complex fitting on the rear axle of the 410. In the end I ended up having VB air suspension fitted by Conrad Anderson in Birmingham. They told me that I was lucky to find a set still in stock in Holland. It wasn't cheap! Overall I have been pleased with them. But I can't help but think it would have been cheaper to just have had new springs fitted. And shocks. Many vans are still on original shocks - and they are also getting hard to find.

All these experiences, and those of others over the years have led me to conclude that I would rather spend money on new springs (and maybe shocks) than on air suspension. But that is my personal opinion.

As an interesting side story ... last year I bought a 670 in Germany and imported it over here. On the drive back I was amazed at the difference compared with my 700. It handled like a saloon car! On closer inspection I found that it had been fitted with Koni shocks, and the tyres were 205R14 as opposed to the usual 185R14s. The springs looked good - it was quite a low mileage van, obviously well looked after. To me, this was proof that these vans can handle well in old age, if you are willing to put in the effort.

Contacts - As well as Conrad Anderson (they are not cheap!) I have heard that the guy at Marcle Leisure is an authority on air suspension. Also Goldschmitt the German company, but I know nothing about them. For springs, new Merc springs are out of the question - they cost telephone numbers! Midland Road Springs, Jones Springs and Rossendale Springs all have a good reputation. There is also a company in Cheshire that does coil spring assisters for motorhomes, but I can't see the point in assisting tired leaf springs with coils.

Tyre pressures are also important. You need the rears pumped up to the max - 65psi. Personally I run my fronts at 50psi, which is below the recommended.

Fwd: Cam lock window stay repair

Look what I've been repairing today!

Took me a while to work out why 2 of my window stays were sliding free and not locking. I had to take a working one apart to see that there is a piece of 5mm o/d steel rod that acts as a cam lock roller, and that this was missing - how, I'll never know!

I replaced it with a bit of 5mm threaded bar that I hacksawed off a bolt. If anything it grips better now because of the thread.

It's a fiddly job, but once you get it apart it is pretty easy. All you need is a philips screwdriver.

Much better than a Mifi for mobile internet ....

For all the internet junkies out there I can highly recommend this bit of kit.

I have been using mifi units from Huawei (with external antenna) for several years, but have found that for full-timing they don't like being plugged in 24/7. The battery gets very hot and expands - I replaced batteries twice - and they don't work without a battery in place. In the end I was worried I was sat on a fire risk. My last mifi battery expanded to the point of popping off its cover.

So I started to research something a bit more robust and came up with this Teltonika RUT240 for £135. Proper piece of commercial kit as used in trucks and buses. Works directly off 9 to 36v DC and has external sockets for both wifi and 3G/4G. It is specced to work in temperatures up to 45 degrees, which is great, because I have it installed inside the wardrobe and it gets hot in there in summer. In this heatwave it is just warm to the touch.

It came with 3 antennas as standard - big high gain ones. I did an experiment and compared 4G signal strength from my roof antenna and the supplied ones, with the unit on the table in the van, but near a window. The signal strengths were almost (but not quite) the same, but miles better than the built in antenna of the little mifi units (or even phones). This leads me to believe that standalone performance would be acceptable to all but purists, and save the hassle of installing an external antenna, while performing much better than a mifi alone. I can imagine it would perform very well on the front dashboard of any Hymer, or against a window.

The interface is very clean, but not fancy. There are a lot of features included that you will never use. I just ran the setup wizard and it worked straight away. A nice feature is that you can control it by SMS from anywhere. I have set it up to send me an SMS when data use hits a certain level. It has all the anoraky things you could possibly want if you are so technically inclined - VPNs and security etc ...

It has a proper SIM slot which enables changing SIM cards easily and on the fly without having to get inside it.

All in all I am very pleased, and I am expecting years of good service without worrying about cooking exploding batteries.

Why I don't check my tyre pressures myself ...

The twin rears on 660/670/700 vans are basically truck wheels and tyres. After 20 years of ownership, I learned the hard way, and I gave up checking my tyre pressures myself years ago . And as for punctures, which are rare, I just limp on 3 rear tyres to safety (front blowouts are different, you should only limp the absolute minimum on the rim - you will ruin the tyre), and then call out breakdown and let them take care of it. I have never successfully managed to undo the rear nuts by hand - they are torqued up with airguns by the fitters and almost impossible to remove with a hand lever/wrench. The other problem is that the supplied bottle Mercedes jack is barely adequate, and is only really usable in absolutely perfect conditions. Most 410D based Hymers are fully loaded at the back - just look at that rear overhang! - and after 25 years the rear springs are tired, making it almost impossible to jack up the rear. So why bother ... that's what breakdown is for. A trolley jack makes short work of it, but who wants to carry one of those?

As for checking the pressures - It is a complete pain in the bum to remove the trims if you have them, and then find an air hose with the right angle nozzle. 90% of all service area air pumps, especially those horrible coin operated ones, are useless - they won't get anywhere near 65psi. And in inexperienced hands you can let out more air than you put in - again I learned the hard way!

Every 3 months or so I just stop by ATS Commercial and ask them to check all my pressures. I always offer to pay, and they never accept. What I have found is that the pressures stay constant for ages and ages, and I have never had a slow puncture. I just drove 5000km over 5 months down Italy and Sardinia, and when I finally called into a garage because I caught a (very rare) puncture in the front, when they checked the rears they were spot on.

I also have the habit of regularly just bending down behind the van, so I can see how the twin tyres sit on the road, every time I fill up, especially on a long journey. You soon get used to the profile, and then you can easily tell if a tyre is going flat.

Of course this is just my personal preference - I am getting on a bit, so anything for an easy life! There is no reason why you can't carry a decent 12v compressor and the correct nozzle, or even a better jack. But new owners should take note - maintaining the pressures and changing tyres on the rear twin wheel Merc Hymers isn't as easy as on a normal family car.

Charging your devices - why not to buy Chinese inverters.

I often get asked about inverters for charging mobile devices - what is the best way? 12v adapters or use an inverter and just plug in the original charger.

If the device is a usb device - phones etc, then fitting 12v USB points is quite easy, they look pretty swish when compared with festoons of wires from cigar plug adapters. Many Hymers have small 12v sockets that look like small cigar sockets, but in fact are quality Hella 12v sockets, and if these are conveniently placed you can use these with USB adapters.

But for anything else that isn't USB, and comes with a black 240v charging block, then it's usually easier to use a small inverter.

Inverters are fine when in use, but they do have the disadvantage that they consume a small amount of power, when switched on doing nothing. You can minimise this by buying a top quality one such as a small Victron. Their entry level 180w model consumes 2.6w under no load, but still on and ready. This is equivalent to 0.2ah which means that leaving it on overnight for say 10 hours, will consume 2ah of your battery, which isn't that bad.

But some of the big Chinese inverters are shocking in this respect - they don't even quote a zero load figure - you have to measure it. I have seen big inverters chewing away through an amp or more, just when switched on doing nothing. On a cloudy day of wildcamping this would be a serious amount of usable power, lost for no good reason.

You simply don't need a 1000w inverter in a van, unless you actually intend to use it - ie a mixer, toaster or hairdryer - and in this case you have to back it up with battery and cabling capable of delivering 100amps! Small inverters are much more efficient, and the Victron is the most efficient for the money. Their 180w model will power a laptop, games consoles and as many phones and pads as you want.

I do keep banging on about Victron inverters, but they are the best for the money. Here is the datasheet.

https://www.victronenergy.com/upload/documents/Datasheet-Phoenix-Inverter-180VA-1200VA-EN.pdf