Category Archives: Technical

Items of a technical nature relating to mechanical, electrical or bodywork issues

Ask The Mechanic – Gas use

There were no questions for The Mechanic
this issue, but with the weather tuning cold
and some members continuing to use their
campervan through the seasons, that means
heating. There are gas heaters on the market
and these are becoming more affordable. Gas
is also used for cooking in many campervans,
so it’s time to talk gas safety!

Types of Gas
Let’s start by looking at the different types of gas
available in the UK and beyond.
All European countries have their
own gas bottle suppliers and each
of these have their own regulators
and adaptors. Campingaz is
available all through Europe in
small bottles which is great for
quick trips or for solo travellers. We (Editors) use
campingaz 907 bottles as they’re fairly readily
available in the UK and abroad and they fit nicely
in the cupboard under our storage trunk!
LPG (or Liquid Petroleum Gas) is the most
common kind used in campervans and motor
homes and it comes in two types; Propane
and Butane. Without going into the differences
between them in chemical structure, here are the
main differences:
Propane
‹ Usually used in vehicles where multiple
appliances will be running off it.
‹ Ideal for cold climates as it operates down
to -40°C!
‹ It’s much lighter and less dense than Butane.
Butane
‹ Operates more efficiently than Propane.
‹ It’s denser than propane, so a bottle of the
same size will hold more gas.
‹ Butane can’t be used at temperatures below
0°C (It cools down to a liquid state).
Different appliances may need one or the other of
the main LPGs to operate effectively, so it’s always
worth checking that before you buy.
Gas Safety Rules
‹ The standard that applies to campervans is
BS EN 1949: 2001 + A1:2013. If you ever want
more information, it is worth looking that up.
‹ There isn’t the same level of regulations
for fitting gas and gas appliances to motor
homes and campervans as there is to houses,
but would still recommend that anyone
installing an appliance is registered.
‹ If you’re installing gas appliances into
your campervan, the British Standard isn’t
mandatory, unless you’re going to be hiring
that vehicle out.
‹ If you are going to be hiring, ensuring that
everything is compliant with the law is down
to you, just as it would be if you owned a
house or flat that you were renting out.
‹ You’re allowed to undertake work yourself
if you’re not a registered gas engineer, as
long as you’re competent. (The definition
of competence is vague, but you’ve got
to ask yourself whether you’d be happy
to undertake the work and have the
responsibility on your shoulders).
‹ There’s a lot that could potentially go wrong,
and the stakes are certainly
high, so it may well
be worth getting a
registered engineer
to fit it.
‹ Registered gas engineers can charge
anywhere between £30 and £100 an hour,
but it’s worth looking around in your area if
and when you need one.

Top Tips for Gas Safety
‹ Ensure the gas is turned off before you travel.
‹ If you’re using your vehicle for work purposes
and carrying compressed gas, you must show
a sticker to alert people.
‹ If you’re not using your vehicle for work, but
still carry compressed gas, it is advised to have
a warning sticker displayed whilst carrying
the gas.
‹ Unless your campervan or motor home has
a rotating rooftop device, you’re limited to
carrying two 10 litre bottles of gas in the UK.
‹ All flammable gasses must be carried upright
at all times.
‹ Make sure you’ve got a Carbon Monoxide
alarm. They might not be stylish, but they’re
potentially lifesaving.
‹ Note that LPG gasses are heavier than air, so
will form a ‘puddle’ on the ground in the event
of a leak.
‹ Floor vents must be kept clear.
‹ If parked up in snow/mud/etc then ensure
that the vents aren’t blocked.
‹ Changing the bottle is the most dangerous
time, always make sure that you know how to
remove and fit the regulator and keep
well away from naked flames when
changing the bottle.
‹ Don’t use a naked flame to look for a leak
(sounds obvious!) and check for pipe leaks by
using water and washing up liquid solution,
bubbles will appear at a leak.
‹ Make sure you have a fire blanket and/or fire
extinguisher, as well as a fire alarm.
‹ If you’ve got an older VW it is recommended
to carry an extinguisher any way, in case of a
dreaded engine fire. Can you really have too
many extinguishers in an old VW?
The rules and tips for gas safety aren’t
complicated and if you keep to them, the use of
gas in your campervan is perfectly safe and an
excellent resource.

Ask The Mechanic – Windscreen wiper condition

This issue, The Mechanic takes a look at
an often overlooked but important issue,
windscreen wiper condition.


Windscreen
wipers are an
invaluable part
of any vehicle,
providing
the driver
with a clear,
unobstructed
view of the
road when it
is needed most. Whether it is rain, sleet, snow or
leaves covering your windscreen, the wiper blades
will quickly and efficiently clear the obstruction,
meaning you can continue your journey in safety.
However, of all the parts of a car which are subject
to wear and tear, windscreen wipers are perhaps
the most fragile. Manufactured from thin rubber,
they are designed to operate smoothly on the
windscreen without damaging the surface of
the glass, yet despite their fragility they are often
required on a daily basis, possibly for long periods
of time during wet weather. In winter they
become frozen to the glass and in summer they
are used to help to clean the windscreen, while
being subjected to high temperatures. It is hardly
surprising then, that windscreen wipers do not
last indefinitely and require regular replacement.
Often the need to replace wipers is overlooked,
although regular servicing and MOT testing
should identify if they are becoming worn.
However, rather than relying on these tests to
assess the condition of the blades, car owners
should be aware of the common signs that the
windscreen wipers are failing, especially with
autumn upon us. So what are they?
Streaking: blades that are in good condition
should clear the rainwater from the windscreen
effortlessly, in one complete action.
This means there should be no streaks of water
where the blade has failed to make contact with
the glass.
Unusual noises: windscreen wipers should
operate with minimal noise or ideally should
be silent. Sounds such as squeaks, screeches
or scrapes could indicate that the blades have
become worn.
Irregular movement: wiper blades which are in
good condition will move smoothly across the
windscreen. As they become worn over time,
you may notice that the blades judder
on operation which is an indication that
replacement may be necessary.
Ragged or distorted blades: visually inspecting
the condition of the windscreen wipers should
be a weekly task for all vehicle owners. By
lifting the arms of the wipers away from the
windscreen, you can quickly assess the condition
of the rubber. Ragged, jagged or distorted edges,
where the blade makes contact with the glass,
should prompt you to replace them immediately.
Worn blades may not only hinder your vision, but
can also damage your windscreen, which will in
turn not only cost you dearly in a replacement
screen, but also hinder your vision even more,
making it dangerous to drive with the vehicle in
such a condition.
Replacement blades can be picked up very
cheaply for all types of van, so there is no excuse
not to check yours and change if required, but
remember… “Buy Nice or Buy Twice”.

Ask The Mechanic – T4 CLUTCH PEDAL SUPPORT BRACKET

The Mechanic features some technical
talk every issue and welcomes member
submissions.
This issue, The Mechanic takes a look at a very
common problem for the T4 Transporter and
how to fix or prevent it from occurring.

A common
problem that
T4’s and their
owners’ suffer
from is the clutch
pedal mounting
bracket cracking.
This in turn then
causes the clutch
master cylinder
to become loose
and move. This may not be a huge problem
in the beginning, but it will eventually break
away completely, leaving you without a
working clutch in your T4 van. As well as the
damaged pedal, it can also damage the master
cylinder beyond repair and/or crack the pipe
work, covering your foot well and footwear in
corrosive brake/clutch fluid.


There is a quick
and affordable
repair/prevention
method by fitting
an additional
angled bracket
that strengthens
the existing pedal bracket. The kits are readily
available online and can be found with a quick
search. The kits contain an angled bracket, three
M8 bolts (one longer than the other two), an M8
nyloc nut and four washers (one larger than the
other three).
Fitting Guide
1 Start off under the bonnet and locate your
brake servo unit. It is the big round unit below
the brake master cylinder and brake fluid
reservoir.
2 Remove the M8 bolt (13mm head) from
the lower right side of your brake servo and
replace it with the longest of the three M8
bolts supplied in the kit, along with the largest
M8 washer.
3 Now move inside the car and into the driver’s
foot well. Locate your clutch master cylinder,
located between the clutch and brake pedals
and remove the two M8 mounting bolts
(13mm heads).
4 Place the new clutch pedal support bracket
into position, ensuring that it goes over the
protruding bulkhead bolt you first fitted. Now
loosely fit the bracket to the clutch master
cylinder using the two remaining M8 bolts
and small M8 washers supplied in the kit with
your support bracket.
5 Now fit the other small M8 washer and M8
nyloc nut to the longer bulkhead bolt you
fitted earlier and tighten.
6 Now tighten the two clutch master cylinder
bolts you fitted loosely earlier.
7 Job complete. Enjoy a strong clutch pedal
and relax knowing that this failure has been
repaired or prevented

Ask The Mechanic – Fitting a hot start relay

If you have an air-cooled van and experience
the dreaded “click” when trying to start your van,
it could be that the original wiring and ignition
switch now has a higher resistance than it did
back in the 70’s and cannot cope with the current
required to turn the engine over using the starter
motor.
One way to counteract this is to fit a relay that
takes the current load and the ignition switch
activates the relay.
A relay sourced for this application can be
purchased from Just Kampers; JK part number
J12928.
Parts required
‹ Suitable cable for wiring the relay – suggest
Halfords 12v 17A cable sold in 4m reels
‹ Several crimp connectors
‹ The relay itself – JK part number J12928
Method
It is advisable to always disconnect the vehicle’s
battery before carrying out any work on the
electrical system.

  1. Mount the relay in a safe place as close to the
    starter motor as possible.
  2. Take the existing wire from terminal 50 on
    the solenoid and extend it to reach the relay
    position.
  3. Connect this extension from terminal 50 on
    the solenoid to terminal 86 on the relay.
  4. Now connect terminal 85 on the relay to a
    good earth on the vehicle body/chassis.
  5. Connect terminal 87 of the relay to the live
    terminal of the vehicle’s battery.
  6. Now connect terminal 30 on the relay back
    to terminal 50 on the starter solenoid.

Whilst every attempt is made to ensure that
these instructions are as accurate and clear as
possible, the author or club itself cannot be
held responsible for misinterpretation of these
instructions or for any subsequent accident or
damage caused through mis-fitted parts.

Ask The Mechanic – Aircooled engine cooling

The summer is here and that hopefully means that
we are experiencing warmer air temperatures.
With warmer air temperatures, comes warmer
engines. Those using aircooled engines will find it
even harder to keep the engine cool during the
summer months and we have all seen the odd VW
at the side of the motorway! Don’t let that be you
(not through overheating anyway!)


Although it may seem like a small detail, to ensure
cooler engine temperatures, it is absolutely vital
that the tinware and engine compartment rubber
seals are all present and intact. This ensures that
there is cool air above the engine and hot air
below it. These are known as the cool and warm
zones. If tinware parts are missing, or the seals
around the front and back of the engine are torn
or broken, hot air will be drawn from the cylinder
heads and exhaust back into the cool zone around
the top of the engine and then sucked in by the
cooling fan and re-circulated over the cylinders
and heads, causing the engine temperature to
rise, potentially to a critical level. This can cause all
kinds of problems over time, some of which may
not be immediately obvious, from hot starting
troubles, to cracked cylinder heads, up to and
including a seized engine.
If you’ve just bought a car/bus, it is well worth
checking the condition of the tinware and seals
and also making sure that there are no foreign
bodies stuck in the cooling fan (remember to do
this with the engine turned off!)
If you are fitting a reconditioned or new engine,
don’t just rely on refitting the parts that were on
the old engine, as they may not be correct either.
The thermostat is another vital piece in the cooling
system. There is a set of flaps inside the fan shroud,
that actually block cooling air when the engine
is cold, in order to warm up the engine more
quickly. These are opened by the thermostat,
located between the cylinder barrels and if this
part is defective your engine will very quickly
overheat. Check the function of the thermostat
and flaps and if required, replace. The alternative
is to completely remove the thermostat and
flaps, which while it certainly simplifies matters,
is not ideal. It means that your engine may never
reach the correct operating temperature in cold
weather conditions.
The last few points to consider are your ignition
timing, air leaks and fuelling. Poor ignition timing
can cause your engine to run too hot, it’s unlikely
to be visible if it’s wrong but you should hear
it. Fuel mixture is equally important, so ensure
the carburettor jetting is correct for the size of
the engine, fuel starvation will raise the engine
temperature internally. Your fuel system could be
setup perfectly, but if your engine is sucking air in
elsewhere through a split hose or a broken gasket,
then the whole fuel/air mixture is compromised
and the chances of running lean and therefore
hot, are increased too. Spraying the intake system
with Wd40 whilst running will help to detect this,
an air leak will suck the spray in, using it as fuel and
changing the engine note at the same time.
I hope there are some helpful tips for members to
help stay cool this summer.

Ask The Mechanic – Checking spark plugs

An article from Chairman Malcolm Marchbank

Spring has sprung and those classics will be
starting to come out of hibernation. After months
in the garage with the occasional start up to
keep it ticking over, your engine can suffer. I have
personally experienced this after months of an
engine sitting during restoration work and being
moved from one side of a workshop to another.
Once the work was complete, trying to drive
away from the workshop, my T2 Bay Campervan
wouldn’t accelerate down the road. Reason –
fouled spark plugs.

I have also had a spark plug with a closed gap
(don’t even ask how that happened, but it
involved losing part of the carburettor through
the engine… lucky it didn’t do any other damage!)
The condition of your spark plugs can make a
massive difference to the running of your engine,
so it’s worth checking them every so often,
especially after a period of time unused.
Hopefully the following information will help to
make you a spark plug expert.
Before starting work on checking your plugs, it is
helpful to have the right tools to hand; accessing
the rear two spark plugs at cylinders 1 and 3
can be a real fiddle, especially on later twin-port
engines where access is further compromised
by the inlet manifolds. A short 21mm socket and
universal joint may give you a bit more flexibility.
When checking the plugs, it can help to remove
each lead and plug individually so that you don’t
get them mixed up. This will cause an incorrect
firing order and your engine will not run.
When removing the ignition lead from the plug,
be sure to pull it off by the connector, not the lead
itself, as you’ll run the risk of pulling the lead off
the connector (trust me!)
If you notice any damage to a connector or if a
lead is a lose fit, it is best to go out and buy a new
HT lead set.
Make sure you have the socket on the plug
properly when you’re undoing them and it’s also
best to do all this while the engine is cold to avoid
burning yourself!
Once the plug is out, take a good look. Is it brown,
grey, sooty or oily? If the engine is running right,
it should be light brown or grey. If it is sooty but
dry, your engine is running rich and not burning
all the fuel. If the insulator is white and flaky then
your engine is running too lean. Either way, you’ll
need to tune your carb to adjust the fuel/air
mixture.
If the plug is wet and oily, there are a couple of
possibilities. The first is that you’re not getting
a spark, in which case you may have noticed
a misfire. If this is the case, check the HT lead
connection at the plug and also where it pushes
into the top of the distributor cap.
A worse scenario is that your engine has worn
piston rings and/or valve guides, which means a
rebuild is on the cards. If there is serious carbon
build up on the plug, or what looks like molten
bits of metal, chances are your ignition timing is
out.
Whatever their condition, while the plugs are out
of the engine they will benefit from a good clean
up using a brass wire brush. While you are at it,
check the spark plug gaps using a feeler gauge.
For most air cooled engines the gap should be
0.024” or 0.6mm, however check your workshop
manual because the gap will be different on
some engines. If the gap is correct, the gauge
should slip in and out without much resistance.
If it is too loose, you can adjust it with a gentle
squeeze in a vice to close it slightly, or if the gap is
too tight, carefully prise open the contact with a
flat bladed screwdriver.
Spark plugs should be checked every 3000 miles
and replaced every 10,000 miles as part of your
service routine. If you suspect a poor running
engine there is no harm fitting new ones sooner,
they are relatively cheap for a set.
When refitting, always start screwing the plug
back in by hand, only using the socket for the
final tightening, otherwise you risk forcing a cross
thread. If you feel any resistance early on, unscrew
and carefully try again

Ask The Mechanic – 171 – E10 fuels

The mechanic has noticed a recent uplift
in questions and concerns surrounding the
upcoming introduction of E10 fuels. The
following is information provided by the
Federation of British Historic Vehicles Clubs
that we hope members will find useful.
Federation of British Historic Vehicles
Clubs – Introduction of E10 petrol
After an extensive consultation process, the
Department for Transport has announced that they
will legislate to introduce E10 petrol as the standard
95-octane petrol grade by 1 September 2021. They
will also require the higher-octane 97+ ‘Super’ grades
to remain E5 to provide protection for owners of
older vehicles. This product will be designated as the
‘Protection’ grade.
The introduction of the 95-octane E10 grade and the
maintenance of the Super E5 protection grade will be
reviewed by the Government after 5 years to ensure
they remain appropriate to the needs of the market:
In relation to the E5 protection grade, such a review
will examine market developments over the period.
HM Government have sought to reassure FBHVC
members and historic vehicle owners that, without
a suitable alternative becoming available, it is highly
likely the Super E5 protection grade would continue
to be available.
Filling stations that stock 2 grades of petrol and
supply at least one million litres of fuel in total each
year will need to ensure one product is the Super E5
protection grade. While not all filling stations meet
these criteria, almost all towns across the UK will have
a filling station that supplies the ‘Super’ grade and
currently one major retailer, a national supermarket
group, has committed to offer the product. The main
exception to this is in certain parts of the Highlands,
north and west coast of Scotland, which will be
covered by an exemption process and allowed to
continue to market the 95-octane E5 grade.
The Federation therefore recommends that all
vehicles produced before 2000 and some vehicles
from the early 2000s that are considered noncompatible with E10 – should use the Super E5
Protection grade where the Ethanol content is limited
to a maximum of 5%. To check compatibility of
vehicles produced since 2000, we recommend using
the new online E10 compatibility checker: https://
www.gov.uk/check-vehicle-e10-petrol .
It should be noted that some Super E5 Protection
grade products do not contain Ethanol as the E5
designation is for fuels containing up to 5% Ethanol.
Similarly E10 petrol can contain between 5.5%
and 10% ethanol by volume. Product availability
varies by manufacturer and geographical location
and enthusiasts should check the situation in their
location.
Latest News:
The federation’s fuels specialist Nigel Elliott has
received some new questions with regards to
ethanol and the use of E10 in historic vehicles and his
thoughts are as follows:
There are three key areas of concern with Ethanol
compatibility with historic and classic vehicle fuel
systems:
‹ Corrosion of metal components
‹ Elastomer compatibility – swelling, shrinking and
cracking of elastomers (seals and flexible pipes)
and other unsuitable gasket materials
‹ Air/fuel ratio enleanment
Corrosion of metal component
Ethanol has increased acidity, conductivity and
inorganic chloride content when compared to
conventional petrol which can cause corrosion
and tarnishing of metal components under certain
conditions. These characteristics are controlled in the
ethanol used to blend E5 and E10 European and UK
petrol by the ethanol fuel specification BS EN15376 in
order to help limit corrosion.
Corrosion inhibitor additives can be very effective
in controlling ethanol derived corrosion and are
recommended to be added to ethanol in the
BS EN15376 standard. It is not clear if corrosion
inhibitors are universally added to ethanol for E5
and E10 blending so as an additional precaution it is
recommended that aftermarket corrosion inhibitor
additives are added to E5 and E10 petrol.
These aftermarket ethanol corrosion inhibitor
additives often called ethanol compatibility
additives are usually combined with a metallic
valve recession additive (VSR) and sometimes an
octane booster and have been found to provide
good protection against metal corrosion in
historic and classic vehicle fuel systems.
Elastomer compatibility
As the ethanol molecule is smaller and more polar
than conventional petrol components, there is
a lower energy barrier for ethanol to diffuse into
elastomer materials. When exposed to petrol/ethanol
blends these materials will swell and soften, resulting
in a weakening of the elastomer structure. On drying
out they can shrink and crack resulting in fuel leaks.
Some aftermarket ethanol compatibility additives
claim complete protection for operating historic and
classic vehicles on E10 petrol. The FBHVC is not aware
of, or has tested any additives that claim complete
fuel system protection with respect to elastomer and
gasket materials for use with E10 petrol. The FBHVC
therefore recommends that elastomer and gasket
materials are replaced with ethanol compatible
materials before operation on E10 petrol.
Air/fuel ratio enleanment
Ethanol contains approximately 35% oxygen by
weight and will therefore result in fuel mixture
enleanment when blended into petrol. Petrol
containing 10% ethanol for example, would
result in a mixture-leaning effect equivalent to
approximately 2.6%, which may be felt as a power
loss, driveability issues (hesitations, flat spots, stalling),
but also could contribute to slightly hotter running.
Adjusting mixture strength (enrichment) to counter
this problem is advised to maintain performance,
driveability and protect the engine from overheating
and knock at high loads.
Modern 3-way catalyst equipped vehicles do not
require mixture adjustment to operate on E10 petrol
because they are equipped with oxygen (lambda)
sensors that detect lean operation and the engine
management system automatically corrects the fuel
mixture for optimum catalyst and vehicle operation.
Operating classic and historic
vehicles on E10 petrol
If you should decide to make the necessary vehicle
fuel system modifications together with the addition
of an aftermarket additive to operate your classic or
historic vehicle on E10 petrol. The FBHVC strongly
recommends that you regularly check the condition
of the vehicle fuel system for elastomer and gasket
material deterioration and metallic components such
as fuel tanks, fuel lines and carburettors for corrosion.
Some plastic components such as carburettor floats
and fuel filter housings may be become discoloured
over time. Plastic carburettor float buoyancy can also
be affected by ethanol and carburettors should be
checked to ensure that float levels are not adversely
affected causing flooding and fuel leaks.
Ethanol is a good solvent and can remove historic
fuel system deposits from fuel tanks and lines and
it is advisable to check fuel filters regularly after the
switch to E10 petrol as they may become blocked
or restricted. If your vehicle is to be laid up for an
extended period of time, it is recommended that the
E10 petrol be replaced with ethanol free petrol which
is available from some fuel suppliers. Do not leave
fuel systems dry, as this can result corrosion and the
shrinking and cracking of elastomers and gaskets as
they dry out

Spares by Ian Crawford

Many people will be away and wish they had something with them – here is a list from club member Ian Crawford on spares he packs in his 1971 Bay window that he bought at 1 year old in 1972. I am not sure about corks – leftover wine is not something I really understand!

Parts
• Accelerator Cable
• Aluminium Tube
(To Fit Inside Fuel Hose
If Leaking)
• Battery Earth Strap
• Brake and Clutch Fluid
• Brake Pedal Return
Spring
• Spare Bulbs
• Cable Ties (Various
Lengths)
• Carburettor Return
Spring
• Clutch Cable
• Coil
• Condenser For
Distributor (Make Sure
You Have The Correct
“Bung”!)
• CV Axle Boot Cap
and Grease
• Distilled Water
• Distributor Cap and
Rotor Arm x2
• Distributor Contact
Points
• Dynamo Brushes
• Engine Oil (5 litres)
• Fan Belt x2
• Fuel Hose and Clips
• Various Fuses
• Handbrake Cable
• Rocker Cover Gaskets
x2
• Spark Plug Set
• Starting Relay and
Fuse
• Tyre Valve Cores
• Voltage Regulator
• Walking Boot Laces

Tools
• Allen Keys
• Battery Diagnostic
Tester
• Feeler Gauges
• Hacksaw Blades
• Insulation Tape
• Magnetic Dish Holder
• Magnifying Glass (My
Eyes Are Dimming!)
• Multi Meter and
Spare Battery
• Plastic Wire Cutters
• Pill Pot Containing
Matches, Lighter,
Flints, Water
Purification Tablets,
Sweeteners, Sewing
Kit, Safety Pins and
Buttons.
• Shorting Links
• Stanley Knife
• Tyre Pressure Gauge
• Vaseline
• Wine Corks
• Other Various Tools
Ian has provided a pretty extensive list here,
very cautious!
We would also recommend a timing gun if space
allows, a foot pump, warning triangle, decent jack,
various sockets and spanners and maybe even a fuel
pump! (We even carried a spare carburettor once!)
Thanks to Ian for his submission, hopefully this will
help members when putting a kit together.

Ask The Mechanic – 169 – Solar Panel Charge Controllers

For this instalment of The mechanic, we welcome a submission from the club’s chairman;
Malcolm Marchbank.
SR PWM MPPT – A question of control


If you have or thinking of getting a PV (photo voltaic)
solar panel, then these terms may concern you.
There have been several articles about the use of
solar panels to provide power in vans when there
is no hook up available. The panel(s) will almost
certainly be used to charge a battery for use when
there is insufficient power available from the sun. The
maximum power available from any panel is in a very
clear set of circumstances, the sun needs to have an
energy at the panel of 1000 watts per square meter,
the sun’s rays must strike the panel perpendicularly,
the air temperature should be 23 deg C. So, if you set
up your panel at noon on a cloud free midsummer’s
day carefully angled so the sun strikes it at 90 deg and
there is a gentle breeze, a 100w rated panel will give
100w of electrical power. In any other circumstances
the power will be substantially less. So, in reality it
is better to estimate the average power to be 30 to
60w from a 100w panel.
The next thing is how to make the most of the power
we do get. If you examine the “rating plate” fitted to
almost all solar panels you will see some numbers.
Ok you see 100w max power but look at the “ipmax”
this is the current at maximum power, ”vpmax” this is
the voltage at maximum power. A typical example
of a 100w panel ip max =5.55a vp max =18v 185.55 =100w. So we need a control unit to regulate the power sent to the leisure battery. Small panels less than about 30cm square sold as “trickle chargers” to maintain a battery while laying on the dashboard have so little power they are self regulating (SR) as the current is so small as never to damage the vehicle battery. Those for phone or device charging rely on the internal battery controller in the device to regulate the power and prevent overcharging of the internal battery. This leaves the choice of the two types of actual control unit PWM (pulse width modulation) or MPPT (maximum power point tracking). At first the generally available controllers were all PWM and cost from £8 up to around £35. These work by monitoring the battery voltage and sending pulses of power to provide an average voltage to the battery. Initially when the battery is low, the power pulses are very wide, but as the battery voltage rises then the pulse width is reduced. It is important then for the controller to “know” when the battery is at full charge so the pulses can be reduced. Different (lead acid) batteries fall into at least 3 types; Flooded, AGM and GEL. Each has a different charging requirement. So, any controller needs to be set to the correct type. Cheaper controllers may have no settings at all or be described as “automatic detection” and are probably best avoided! When you look at the typical full power voltage and current from a solar panel you will notice the voltage is too high as the maximum needed for the battery is 14v so the best this controller can do is to give 145.5=77w. The rest of the power is wasted due to
the effective internal panel resistance.


So around 25% of the power we do get is just
wasted, to overcome this a MPPT controller can be
used. This is often a combination of PWM control (for
trickle charging when full power is not needed) and
an inverter which is controlled by a microprocessor.
This changes the 18v 5.55a into 14v 7a, this is an
example as the controller constantly measures both
panel output (change in sun intensity) and battery
condition (low, charging, full) and adjusts the inverter
to maximise the power to the battery. This results in
an efficiency of better than 95%.
SOLAR PANEL CHARGE CONTROLLERS
Transporter Talk Issue 169 | 23
I have tested this and can confirm that just changing
the controller increased the current from 5a to 7a
. If as I have, you have more than one solar panel
(I use 3) and they are all slightly different outputs,
the MPPT sorts out the balance even when one is in
shade and 2 are in sun.
The MPPT controller is as you would expect, more
complex and expensive up to around £70. This may
mean that some suppliers may claim to be MPPT
when they are not. I was fooled by this but claimed
back from the seller as the description was clearly
false. I have some photographs of the various types;
PWM 10 amp, fake MPPT (plenty of usb points on it!)
and a real MPPT 10 amp unit. So check that you get
the correct item!
I have 2 panels on the roof of my Westy and when
raised the angle is quite close to optimum. I also have
one on the front luggage rack so I can get power
even as the sun passes over. I have this arrangement
to support not only lights and water pump, but the
compressor fridge that is of course run 24/7. I would

not want to run out of ice for our G&T’s after all!
Malcolm

Ask The Mechanic – 168 – Replacing the brake master cylinder

For this installment of The mechanic, we welcome a submission from Jonathan Bruton. You may recall his submission for issue TT166 concerning brake overhaul, this is the second chapter of that story.
Not long after I had put my tools away and given
myself a smug pat on the back for having successfully
installed new callipers and discs on the front wheels
of Mortimer Henderson (TT Issue 166), my ’73 Bay, I
happened to see a Facebook post from Nick Gillott
to the effect that the master cylinder also needed
replacing at regular intervals. The master cylinder, as
its name suggests, pushes brake fluid through the
lines to the slave cylinders at the wheels when you
hit the brake pedal, operating the brakes through
hydraulic pressure.
Anyway, I tried to ignore this unwelcome piece of
advice but could no longer do so when it became
obvious that the pedal was getting spongier by the
journey; when I finally got around to checking the
level of the reservoir, it had gone down quite sharply,
and I could see brake fluid dripping out of the hole
in the front pan beneath the pedal assemblies. So,
action was clearly needed.


Once the pan was removed, the first thing to do
was to locate the cylinder, which I had never looked
for or seen. As you would expect, it is bolted to the
frame beneath the brake pedal assembly, and the
brake pedal rod fits into it through a rubber boot,
which itself fits through a hole in the frame and is
designed to keep out dirt and debris. Two brake lines
lead away from it – one to a T-piece which then feeds
the front wheel brake assemblies, and the other to a
pressure equaliser bolted to the offside edge of the
frame, which feeds the rear brakes.
The main fluid reservoir crouches on it piggyback style and is attached via two nozzles that run
through rubber grommets. Finally, the brake light
switch screws in at the back (on my replacement
cylinder, there were two holes for the switch, and
a video I watched for the same job on an early Bay
showed two brake light switches, for reasons I’m not
clear about).


At first glance it was immediately apparent that all
was indeed not well. The boot was in shreds, and the
assembly was clearly leaking, presumably because
dirt had penetrated the seal. But replacing it looked
pretty straight forward, and I naively anticipated that
it’d be done in a single afternoon! It really needed
to be as well, because we only have one parking
space, which has the charger for our main car, a fully
electric Nissan Leaf, which we can’t use if it’s blocked
by a hulking great immobilised van! This has been a
point of friction between me and my long-suffering
partner in the past, but I blithely assured her that
there would be minimal disruption.
In this optimistic spirit, I ordered the replacement
part from JK and offered it up to make sure it was the
same as the one on the van, which it was. So now it
was a matter of whipping off the two 13 mm nuts
holding it on, unplugging the brake light switch and
undoing the two brake pipes, emptying the fluid
reservoir in the process. Yeah, right!
For some reason best known to themselves, VW had
opted for nuts and bolts rather than studs to hold
the cylinder on. Which would inevitably mean that
the whole bolt would just start rotating. Which both
of them did. With one of them, I could get a wrench
on the bolt head and get the nut off no problem.
The other one, however, was conveniently located
in a recess, making it impossible to access with a
wrench, so there was no way to hold the bolt still. In
the end I had to resort to a mechanical nut splitter to
remove the offending nut. With a bit of persuasion
by hammer, I was then able to loosen the cylinder
and start moving it backwards.
The next issue was with the two brake pipes. When
new, of course, the nut rotates freely around the
pipe. After 47 years of exposure to God knows what,
however, muck and corrosion do their worst, and
the nut sticks fast to the pipe. Once I’d been forced
to buy a new 11 mm wrench (inevitably, the only
wrench missing from my set was the one I needed), I
ended up doing what the guy in the early Bay video
had earnestly warned me I really didn’t want to do,
which was to shear both of the nuts right off. After
a few seconds of panic, however, I realised that both
sections of pipe were relatively short and could
easily be unbolted from the other end: at the abovementioned T-junction and the pressure equaliser.


Perhaps this kind of damage is more consequential
in an early Bay. Whatever, I then relaxed and let the
brake fluid drain out through the fractured pipe ends
into a handy receptacle below. My advice would be
to assume that these pipes are going to be toast and
simply order replacements when you order a new
cylinder; it’s no big deal.
So, having broken both pipes and removed the
retaining bolts, I took the cap off the brake light
switch and pulled the cylinder out, complete with
fluid reservoir. Now, this is attached to the secondary
reservoir in the cab by a length of plastic pipe held
in with two plastic hose clips, themselves secured by
two tiny cross-headed screws. These are a bit pesky
to reach, but I got the lower one out easily enough,
assuming I wouldn’t need to move the uppermost
one, and removed the whole assembly.
The reservoir plugs into the cylinder in two places, as
I said above, and it’s a very tight fit – which it needs
to be – so I had to use a screwdriver to exert some
leverage to get it off. No problem there. It was in
good nick, with no cracks or splits, so I could simply
reuse it. The new cylinder comes with the sealing
grommets, so you just have to use some elbow
grease to push the reservoir on. Just make sure you
get it the right way round! Once it was all in place,
I bolted the cylinder in place, having replaced both
nuts and bolts.
Annoyingly, I missed the delivery driver when he
came with the new brake pipes the following day.
That day being Friday, it meant that the van would
have to sit on the space until at least Monday. I
averted a charging-related roasting by offering to
take the Leaf up to the nearest charging station,
so harmony was restored. Monday came and
the eagerly awaited pipes with it. As they have a
diameter of 3/16 “, they’re very easy to bend without
kinking. The only issue here was that the length of
pipe that went to the pressure equaliser was only
just long enough, meaning that I had to carefully
plan the shortest possible distance.
Having removed the old pipes, it was then something
of an epic task to get the nuts to engage with the
threads at both ends – I would get one in place, only
to find that the other end simply wouldn’t oblige. In
the end, I had to loosen the cylinder body again, and,
after rather a lot of swearing, the nuts were finally in
place, and I could reattach the cylinder to the frame
and reinsert the brake pedal rod into the boot.
Surely it would now just be a simple matter of
reattaching the plastic pipe to the bottom reservoir,
refilling it with fresh fluid, and bleeding the brakes.
Ahem. Not quite.
To start with, there was the second hole for the
missing brake light switch. Not much point putting
fluid in for it simply to run out again through a
great big hole. As automotive bolt threads seem to

be narrower than their DIY counterparts, my local
hardware store was unable to provide a suitable
blank. Happily, they directed me to a garage round
the corner, and the chap there fished around until
he found a bolt with a nipple, which looked like it
came from a carburettor assembly, that had the right
thread and would do the job. Now, it would surely
all work.
With great lightness of heart, I tightened everything
up and started to refill the cab reservoir – only
to discover that the fluid was dripping out at the
bottom almost as fast as it was going in! Yes – it
was the hose. Leaking at both ends. Meaning that,
to investigate, I’d also have to undo the topmost
clamp, which was virtually impossible to reach
from underneath. Filing that away as a problem for
later, I replaced the pathetic little plastic clip at the
bottom end of the hose – where it joined the lower
reservoir – with a proper jubilee clip and tightened
it nice and snug. I then had the blindingly obvious
realisation that it would surely be possible to undo
the reservoir in the cab and lift it out to get access
to the clamp immediately below it. But I couldn’t see
how to release the reservoir. Fortunately, the Samba
came to the rescue, and I was soon undoing the two
little screws that held it in, which enabled me to lift
up the reservoir and shed light on the problem.
Sure enough, the hose at the top end was split, so I
trimmed it and replaced the plastic clip with another
metal pipe clamp. I also realised that the nozzle (I
can’t think of the proper word for the protruding part
the clamp attaches to!) and was supposed to have a
plastic sleeve around it to aid the seal, but this sleeve
was missing from both ends, so all I could do was
make sure the clamps were located on the slight
bulge in the nozzle and done up nice and tight.
And then – glory be! – the leak was finally sorted!
I filled her up and fetched my handy little Draper oneman bleeding kit, which is a bottle with a one-way
plastic hose that fits snugly over the bleed nipple
and doesn’t permit any backflow. When you’re lying
under the van, you can operate the brake pedal from
underneath and watch as the air bubbles shoot out
of the bleed nipple and disappear into the bottle,
to be replaced by a lovely golden bar of brake fluid,
which is a fine sight.
So, there it was. All done. Except that I couldn’t find
the cab fluid reservoir cap. Anywhere. I’m sure many
of you will know what it’s like not to be able to find
the tool you’ve just put down and to have to spend
ten minutes searching for it until you find it in your
pocket or somewhere. Anyway, as my frustration
and incredulity increased, I resorted to rummaging
through the recycling until I found the top of a
squash bottle which could be made to fit. Better
than nothing! Anyway, I could finally triumphantly
drive the bus off the parking space and swap it for
the Leaf, which I plugged in, thereby ensuring that
domestic harmony would continue without a ripple.
And then, there was the reservoir cap. Perched
on top of a wheelie bin, where I’d left it. Laughing
at me.
Jonathan Bruton