Caswell Road
Brackmills Indust Est.
Northampton
Northants,
England
United Kingdom
NN4 7PW
Tel: +44 (0)1604 701111
Fax: +44 (0)1604 701120
Email: enquiries@miswa.com
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BRAKE FLUID TESTING REQUIREMENTS
At Miswa we are proud of the quality of our products. Our confidence is built on a bedrock of testing which we carry out in our own laboratory, and for your information we have included below a glossary of some of the tests we employ. We feel it is important, when comparing competing products, that one is comparing like with like.
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POLYGARD DOT3 and DOT4 Brake and Clutch Fluid Testing
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All Polygard Brake Fluids conform to all internationally recognised standards.
Indeed, to ensure the extra quality of POLYGARD brake fluid, extra QC tests are performed over and above those stipulated by the international standards. These tests, including specific gravity, water content, appearance and refractive index, are an added measure to guarantee the very best product performance.
| EQUILIBRIUM REFLUX BOILING POINT
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This shows the brake fluid, when first produced, has a boiling point significantly above the operating temperature in the braking system and ensures an acceptable in service lifetime.
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WET EQUILIBRIUM REFLUX BOILING POINT
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During the first 2 years of service the
brake fluid will pick up about 3.5% of
water which will cause the boiling point
to fall. To ensure no loss of brake
performance is experienced this is
simulated in the wet boiling point test.
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VISCOSITY AT -40 DEG C
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Ambient temperatures as low as -40 deg
C may be met in some countries. At these
temperatures the brake fluid becomes
much more viscous. This could interfere
with the working of the hydraulics and
cause the brakes to fail. This test
measures the viscosity and ensures the
fluid will perform satisfactorily in even
the harshest climate.
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VISCOSITY AT 100 DEG C
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Under normal operating conditions the
brake fluid will reach temperatures
around 100 deg C and the viscosity will
drop significantly. If the fluid is too thin
leakage in the hydraulic system could
occur leading to ineffective brakes. This
test ensures the brake fluid viscosity at
high temperature will allow satisfactory
operation of the braking system.
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PH TEST
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This standard chemical test provides a
measure of the balance of the inhibitors
added to protect against corrosion of the
metal components of the braking system.
It also ensures the brake fluid is correctly
formulated to neutralise the harmful
effects of any acidic degradation product
formed during product service.
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HIGH TEMPERATURE STABILITY
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Brake fluids operate at high temperatures
for long periods of time. If not correctly
formulated with anti oxidants severe
degradation can occur leading to loss of
boiling point and the formation of
corrosive by products. This test measures
the resistance of the brake fluid to this.
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CHEMICAL STABILITY
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In service brake fluids from different
manufacturers may become mixed. This
test simulates this using a reference fluid
of defined composition which is mixed in
equal volumes with the brake fluid. The
stability of the mix at high temperature is
then measured. The test ensures the
product is chemically compatible with
other fluids over extended periods of
time at high temperature.
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CORROSION
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This test exposes the 7 metals commonly
used in braking systems to a sample of
wet brake fluid at 100 deg C for 120
hours. Weight losses are measured and
the appearance of the metal coupons
examined upon completion of the test.
The results indicate the degree of
corrosion protection the fluid will afford.
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EVAPORATION
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Brake fluids operate at high temperatures
for extended periods of time. If the fluid is
not correctly formulated excessive
evaporation could occur resulting in too
low a fluid level to allow satisfactory
operation of the braking system. Measuring
the rate of evaporation by this test ensures
product will perform satisfactorily.
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EFFECT ON ELASTOMERS
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Elastomers are used to produce the seals
and hoses in the brake system. To ensure
satisfactory long term performance it is
essential the brake fluid is compatible with
these. Samples of the elastomers are placed
in the fluid at elevated temperature for a
specified period of time. Any changes in
the dimensions or hardness must fall within
defined limits.
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SPECIFIC GRAVITY
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This is an additional test to those listed in
the international specifications but is
useful as an indication of product
consistency. It is also necessary for
calculation of fill volumes from weight
checks.
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WATER CONTENT
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As the water content of the brake fluid
increases the reflux boiling point
decreases. Therefore it is necessary
during production to minimise any water
pick up. This test can be used to measure
the brake fluid water content at each stage
of manufacturing prior to packing.
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FLUIDITY AT LOW TEMPERATURES
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An additional test to the -40 deg C
viscosity. This is conducted at -50 and
-40 deg C
and determines whether or not the fluid
remains liquid. It gives an extra degree of
safety where arctic conditions may be
encountered.
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WATER TOLERANCE
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This test determines the brake fluids
behaviour at -40 and 60 deg C after
water pick up. It ensures the fluid remains
liquid and the water content does not lead
to precipitation of additives which could
lead to blockages in the hydraulic lines.
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COMPATIBILITY
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An additional check on the compatibility
of the brake fluid with other products.
Equal volume mixes with a reference
fluid are stored at -40 and 60 deg C. At
the end of the 24 hour test the samples
should still be clear and show no sign
of precipitate.
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OXIDATION RESISTANCE
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Brake fluids must show high resistance
to oxidation during their service life as
the by products of this process are
corrosive and may lead to solid build
up in the brake pipes. This test subjects
the fluid to extreme conditions and
measures corrosion on aluminium and
cast iron and any tendency to gum
formation which could lead to sticking
of moving parts in the brake system.
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STROKING TEST
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This is an accelerated aging test which
simulates the braking process and
repeats it 85,000 times under varying
temperature conditions. At the end of
the test the rig is examined for fluid
loss and damage to the components. If
test parameters are met the fluid will
perform satisfactorily over its service
life providing usage recommendations
are followed.
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