I took the car for the IVA test on the 1st October 2009,
and to my horror it failed. I was hoping for a
pass after the effort that had gone into the car, but as
others have said, at least i know what must now be done
to get it through.
Below are the results sheets from the test so that all
can see and hopefully learn for my errors. The
links above show the build stages, so this page shows
what I did to hopefully solve the fails.
Starting from the first point,
control/Mechanical components. Brake Master Cylinder
retaining bolts not fitted with a locking device.
I had not used Ny-lock nuts when fastening the master
brake cylinder, a simple and silly mistake.
There must not be
a feel of sponginess indicating air in the system!
Well I must have bled the system about 4 or 5 times so
if there is air in the system it was not for leaving
the pipes. I had a think and read of the Sierra
manual, one possibility was weeping of the master
cylinder seals. So I decided the only safe course of
action was a new master cylinder, the seals are no
longer available on their own.
When I removed the old MC I did notice a very small
amount of brake fluid around the push rod section, so
perhaps not a bad idea to go for new.
I also thought about the pipe layout and particularly
the brake light switch. This is elevated
above the master cylinder and perhaps air was getting
trapped in that section of pipe. So a new switch
mounting has been made allowing the fitting of a bleed
nipple, so that air could now be purged from that
section as well as the wheel slave cylinders.
The braking ratio
of the axles, for all values of brake force must be
less then the frictional force ratio etc.
Basically means that under braking when weight is
transferred from the back axle to the front axle, the
brake must be less that then friction on the
tyres. The back wheels must not lock up before
the front wheels under all loads.
Below is the results of the brake tests.
I was given a clue! Lose a bit from the rear
brakes or get a bit more on the front. One section
above that shows the brake efficiency at 53.78% front
and 45.78% on the rear, means they are too close so that
when weight transfer happens the rear would lock before
the front and could lead to a spin.
One way to sort the problem would have been to use an
adjustable regulator to the rear brakes. This is
no longer allowed for IVA even if it is then locked when
done. So another way has been sought.
It took a lot to figure the weight transfer, or weight
distribution ratio as mentioned above, but the Internet
came to the rescue and after some searching for answers,
I was able to write a spreadsheet, enter the data from
weights and braking forces and for it to work out the
end results as above.
The next step is to solve the problem and after talking
with a rep from Brake Engineering I have decided to
reduce the rear slave cylinder size.
The standard Sierra cylinder has a bore of 22.22mm, but
there are other cylinders that match the external
dimensions but have bore sizes of 20.64 mm 19.05 mm and
17.46 mm. So the spread sheet was changed to allow
me to work out the brake forces that would act on the
back wheels, all else staying the same. This
allowed me to make theoretical changes and watch the
predicted brake distribution and weight distribution
The spreadsheet is here for anyone to try: - braketest.xls
I have chosen to fit the 19.05 mm rear cylinders, which
I hope will give me an approx 60/40 split on the
front/rear brakes. This is work in progress.
Side repeater body
and N/S and O/S Int. These must also
follow if above 3.2 mm from the bodywork have the 2.5 mm
rule. These have now been covered by rubber hose
to solve this issue, this is glued into position over
foam on the body of the repeaters. The repeaters
them selves give me another problem elsewhere!
More to follow!
19th October 2009
Picture of the new brake switch adapter that should
allow air to be bled from the system.
Strength For outboard seats the height of the top of the
head restraint above the R point must be at least 700
mm. Now this equates to 753 mm from the
seat area on a line parallel to the seat back! The
problem arises in that my seats are designed to fold
down flat and the headrest will go very low to achieve
this. The fix is to sleeve the head restraint
bars, so that the head rest will not go fully down into
the seat. It means the head rest may have to be
removed to fold the seat down, but so be it.
All ‘hard’ parts
contactable with a 100mm sphere, which form an
external surface or protrude 5mm or more from the
external surface must have a radius of curvature of at
least 2.5mm. Headlight Mounts/Rear reflectors and
This 100 mm sphere that represents a knee coming into
impact with the car, can come in from any angle, no
longer from just a forward direction, otherwise the
headlight mounts would be covered by the front indicator
The bar that holds the headlights has been
redesigned. It is also wider to give more spacing
between the front indicators as I am still loathe to
mount them from the nose cone. A small amount of
lathe work is still to be done in making two end caps,
but that job is all but complete.
The two rear reflectors, the 60 mm red disks on the back
of the rear arches are 6.2 mm thick and the rounded edge
does not conform to 2.5 mm radius. It was
suggested that I glue a large O ring on each of them,
but I am looking to make two aluminium bezels. My
reasoning is that any trim fitted to solve an issue will
not be falling off after IVA.
The interior mirror has an edge of 1 mm plastic and the
edge facing the driver needs to have a 2.5 mm radius, so
I will either fit some form of edge trim or get another
convex mirror that will pass.
indicators are positioned more than 400 mm inboard
widest part. & Angles of visibility on side
repeaters not met.
I could have kicked myself over this! The rear
wings are the widest part of the car and these are the
second pair of wings the moulds for the first set were
wrong. These new wings are an inch wider then
original, so they add approx 50 mm to the width of the
car. The indicators were over the 400 mm distance
per side by 15 mm but would have been fine for the
original wings. This has now been sorted by the
new headlight bracket.
The side repeaters need to be seen from an angle of 5
degrees to 60 degrees rearward of the vehicle along a
line formed by the extreme outer edge. This outer
edge is made by the rear arches, and so the only
way for the side repeaters to meet the requirements is
for them to be mounted on the outside edge of the rear
does that make the car wider still? This
is still under review and I need to ask again of the
inspection team for an answer.
Rear Fog Lights
RS3, RS4 & RS6
are all due to the wiring loom as supplied, compliant
for the SVA, but not IVA. The fog lights could be
switched on from the side light position and not just
the headlights. The RS10 & RS11 relate to the tell tale
light. It had one but the wrong light, the switch
would light up, but you could only notice it in the dark
so not good enough. This has been partly fixed by
an earth return from the headlight position of the
indicator stalks, this will feed a relay through
the fog light switch to only switch the rear light on
correctly. I have ordered a tell tale light that
has the correct symbol and can be seen under daylight
ball joints not fitted with lock nuts.
OK, so other builders of the Roadster will know there
are no ball joints on the rear suspension, but it means
the rear camber adjusters. These are 20 mm
threaded bars that fit into the top wishbone, they can
not rotate and become loose, but fitting lock nuts will
stop any wear happening to the threads. A valid point, I
have now got the lock nuts and will fit when the rear
axle come off to fit the new brake cylinders.
RS7 wiring under
dash / Protect battery terminals / wiring passing
through un-grommeted holes at headlight
Wiring under dash now sorted, more insulation tape
around wires as in a normal car loom and a few more tie
raps used. The un-grommeted holes I have sorted with the
new headlight mount. Still to find battery
terminal covers or a complete cover for the battery.
Fitted the new brake switch adapter today, also the
switch, relay and lamp for the fog light. Took a
trip down to a few breakers yards to get some battery
terminal covers and also swapped the offside rear brake
cylinder for the smaller size and fitted the lock nut to
the top wishbone. If the weather holds tomorrow I
will do the near side.
Here is a picture of the modufied headlight bracket
showing how I solved the sharp edge problem, still to
make the end cap and come up with a tidier way to hold
the cable to the indicator, it could run internal I
The silver nut at the bottom will have a 12 mm nut cover
Finished the rear brake cylinders and lock-nuts on the
wishbones. Filled and bled the brake lines, the
Easybleed make life easy when doing it on your
own. Car is still on the trailer so no chance to
try the brakes yet.
Made the aluminium bezels for the rear reflectors, not
sure if I will use them! They look fine, but have
seen some nice chrome finished reflectors from SVC, so
if I get chance to see a few I may pick them up.
Managed to scrounge some rubber sheet for the battery
top so that is now covered
OK so a little while since last update, but I have been
Now I hope to have all the points covered, but only time
and retest will tell me if it is enough. The
secondary side repeaters have been fitted to the wings,
small lamps in the outer edge.
Not sure if you will notice it or not in the next
The headrests have the tubing fitted and glued to stop
them retracting in too far. The battery cover with
terminal covers. Then there is the rubber piece
over the internal body of the normal side
repeaters. The wires have also been rapped and tie
rapped to the frame.
The centre mirror was edged with grommet strip and then
a cable cover glued over the top to finish.
Another close up of the headlight bracket, now with it's
end plug. Lastly the locknut on the rear camber
I did buy some different rear reflectors, but to be
honest prefer my own. Will take the car to a
garage Saturday to test the brakes, it will not be a
comprehensive test as with the IVA, but hope to get
figures from it all the same.
The brake tests on standard MOT rollers gave indications
of back breaks locking at around 100 Kg and front around
130 Kg, unfortunately no way of indicating balance and
the point at which they lock up is dependent on the
weight of the axle. So having a re-think on this
and trying to figure a way of measuring brake pedal
To that end I came up with this!
A clutch slave cylinder from a Honda motorbike and a
pressure gauge. Due to the cylinder size, 2 bar
indicated is approx 23 Kg pressure on the pedal.
This needs to be a higher figure so an addition of a
spring should help. The idea is to strap the
cylinder to the base of the foot and read the pedal
pressure on the gauge. It does not need to be
accurate just repeatable so the same effort can be
applied at various stages to test both axles.
Changed my idea for the new side repeaters. At an
auto jumble I spotted another variety of small
amber lamp holders, and bulbs for them arrived in the
post today. They are a lot brighter and give a
better viewing angle as you can see from this simple 12
volt battery test.
I should have them fitted tomorrow night. These
have removable lenses so makes it a lot easier when you
need to fit replacement bulbs. Silicone sealant will be
used on the inside of the wing and the smaller size will
give more clearance from the tyre.
Completed fitting the lamps over the weekend, once again
I bled the brakes to ensure no air came out of the
system, there was none but needed to be sure. I
managed to book my IVA retest for the 23rd.
So now it is just a matter of waiting, and keeping my
Thought I would post a picture of the lights fitted,
would like comments as to suitability if possible.
So here we have the new light fitted, not as sleek
The second view is looking under the wing, you can see
one of the clips that holds the plastic tube with the
wire s running internally and the end of the lamp holder
covered in silicone, plenty of clearance from the tyre.
When I last took the car out on the trailer, the tarp I
used caused a lot of scratches on the rear arches and
bonnet. So I treated the car to a small car
cover, it is not tailor fitted but a standard
small car size costing about £19. I will used
elasticated straps under the car to pull it tight so
should provide better protection?
The car has
passed retest. All the time now seems to be worth
it and I can look forward to getting the registration
number, taxing the car to finally drive it on the
road. Bit out of season, but hope to get some good
Just a couple of pictures to close the pages off, two of
the car at the centre, wet!
Next the main one, a copy of a copy of the IVA test
certificate with a few bits blanked out. The main
one is now with DVLA.