From: Liberty Krueger (libertyk@bellatlantic.net)
Date: Sat Nov 09 2002 - 09:02:03 PST
Incorrect. Never mix DOT-3 and DOT-5. They are not chemicaly compatible.
When mixed they will begin to break down into a milky white residue. This
residue doesn't make and effective break fluid and won't protect against
corrosion or protect the seals. Never convert to a different type of brake
fluid without changing the seals in the system because not all seal material
is compatible with all fluids. If you use the wrong fluid it can break down
the seal material and cause them to fail. Also the master cylinder is not
vented to ambient air. The cap of the master cylinder should have a rubber
bladder that separates the fluid in the reservior from the ambient air. If
this rubber bladder is missing from the cap it should be replaced.
Protecting the paint isn't the reason the military uses DOT-5. DOT-3 fluid
begins to absorb water the moment that the seal is broken on the container
it comes in and must be used immediately to maintain it's DOT rating. Any
unused portion that is left over must be discarded after a few days because
it's DOT rating can't be assured. The military converted to DOT-5 because it
doesn't require any special handling and because it's DOT rating remains
constant over the life of the product. Unused portions can be kept
indefinitly with thier DOT ratings assured. Also vehicles that sit unused
for extended periods of time experience no degradation of the brake fluids
DOT rating when using DOT-5. With DOT-3 it's rating begins to degrade
immediately after it's installed whether the vehicle is being used or not.
>
> Fact:When you accidentally add DOT-3 to DOT-5, you still have a complete
> hydraulic system. The brakes will not fail. Most brake systems probably
end
> up with some water in them as a result of condensation (the master
cylinder
> is vented and exposed to the ambient air at all times), but the system
still
> works just fine with those two fluids. In the long run, there may be some
> corrosion. This corrosion is more of a problem with DOT-5 since water may
> collect at low points. Remember that the truck was designed for DOT-3
fluid
> and water mixes with DOT-3 but not with DOT-5 and seals etc are compatible
> with DOT-3 for sure.
>
> Question: What is the real reason for using DOT-5 in MV's?
> Personal opinion: DOT-5 was specified because it does not act as a paint
> remover when spilled.
>
> Fact:When you pour DOT-3 fluid into a reservoir with DOT-5, then the DOT-3
> sinks to the bottom, the fluids do not mix, but you still have a hydraulic
> system of non-compressible fluids.
> Assumption:There may be some problems at the extremes when the differences
> in boiling points come into play, but having water in the system would be
> more of a problem with its lower boiling point.
>
> Question: Would this statement be correct? "As long as the fluids are not
> brought to a boil (from extreme driving, mountains etc), there is no
reason
> to be concerned when there are more than one type of fluid in the
hydraulic
> (brake) system".
>
> Bjorn
>
>
>
>
>
>
>
>
>
> _________________________________________________________________
> Add photos to your messages with MSN 8. Get 2 months FREE*.
> http://join.msn.com/?page=features/featuredemail
>
>
> ===Mil-Veh is a member-supported mailing list===
> To unsubscribe, send e-mail to: <mil-veh-off@mil-veh.org>
> To switch to the DIGEST mode, send e-mail to <mil-veh-digest@mil-veh.org>
> To reach a human, contact <ack@mil-veh.org>
This archive was generated by hypermail 2.1.4 : Wed Apr 23 2003 - 13:37:50 PDT