Re: [Chrysler300] DOT Choice

[George McKovich <george@xxxxxxxxxxxx>]

And it takes paint off really good!


Sent from my iPhone 4


On Oct 14, 2010, at 8:30 PM, Edward Mills Antique Tractors <millserAT@xxxxxxxxxxxxx> wrote:

> OK - I did NOT work for the government - but I did race cars in the 70's and 80's. 
> 
> The points made against DOT5 are valid. 
> 
> I'll stay with DOT3 or DOT4. Only difference between 3 and 4 is somewhat higher boiling point.
> 
> Best, Ed
> 
> 
> On 10/14/2010 9:25 PM, George McKovich wrote:
>> 
>> All I had to hear was "I worked for the government" to convince me to stay with dot5.
>> 
>> George
>> 
>> Sent from my iPhone 4
>> 
>> On Oct 14, 2010, at 8:07 PM, Herb <zephyr9900@xxxxxxxxxxx> wrote:
>> 
>> > With all the talk about brakes and fluids, All I can say is your looking for
>> > trouble with DOT 5. Once you change over you cant go back unless you
>> > replace EVERY rubber part in your brake system. Dot 4 does every thing DOT
>> > 5 does except contaminate the system with silicone, unless you live on the
>> > north or south pole, or are running a dedicated race car, DON'T DO IT. 
>> > Extreme and I mean Extreme heat or cold conditions are all that I can
>> > justify the use of DOT 5. I worked for the government and converted
>> > hundreds of vehicles over to DOT 5, that experience is the reason I wont do
>> > it to my cars. We kept consistently busy fixing DOT 5 related brake
>> > problems. The only reason they do change to DOT 5 is any vehicle can
>> > potentially go to any place in the world at any time, or that is the logic
>> > in the manual. I know, I know DOT 5 wont absorb moisture, that is correct
>> > but were does the moisture go??? O ya water is heaver than DOT 5, down to
>> > the bottom of the wheel cylinders and calipers to stay, and that is why they
>> > start leaking from the corrosion on the sealing serfaces. If you completely
>> > purge or bleed your brake system every 30,000 or 35,000 like your supposed
>> > to, you will never have corrosion problems with DOT 3 or 4 because the
>> > moisture that is absorbed by the DOT 3 is gone when you do a system bleed.. 
>> > Problem is no one ever purges the system, out of sight out of mind until you
>> > have brake problems, Same with Transmissions, no one changes fluid & filter
>> > or thinks about it till a problem arises and by then it's tooooo late. O,Ya
>> > when you bleed DOT 5 were does the moisture go? OOps, it is still at the
>> > bottom of the wheel cylinders and calipers because it is not absorbed and is
>> > heaver than DOT 5!! That said this is not an overnight problem with any
>> > brake fluid, most of our cars are forty five years old or older and the
>> > brake problems are just showing up. Actually I think the moisture that is
>> > absorbed, is really a good thing if you service your system on a regular
>> > basis. That is why I invested in a power bleeder, about every five or six
>> > years I purge the systems on my cars and never have any problems other than
>> > replacing shoes or pads. Here is an article that is good information. This
>> > is just my $00.02 worth from experience, and I know everyone has a
>> > conflicting opinion, this is just mine. 
>> > 
>> > 
>> > Battle of the DOTs 
>> > DOT 3-4 Verses DOT 5. Which brake fluid should I use? 
>> > "With regards to the DOT 3-4 verses DOT 5 brake fluid controversy, here is
>> > an article sent to me by Mr. Steve Wall. It is one of the most professional
>> > treatments I have seen on the subject". 
>> > [I had to condense this article from 6 pages to 1 due to space limitations. 
>> > Brake Fluid Facts 
>> > By Steve Wall 
>> > As a former materials engineering supervisor at a major automotive brake
>> > system supplier, I feel both qualified and obligated to inject some material
>> > science facts into the murky debate about DOT 5 verses DOT 3-4 brake fluids.
>> > The important technical issues governing the use of a particular
>> > specification brake fluid are as follows: 
>> > 1. Fluid compatibility with the brake system rubber, plastic and metal
>> > components. 
>> > 2. Water absorption and corrosion. 
>> > 3. Fluid boiling point and other physical characteristics. 
>> > 4. Brake system contamination and sludging. 
>> > Additionally, some technical comments will be made about the new brake fluid
>> > formulations appearing on the scene. 
>> > First of all, it's important to understand the chemical nature of brake
>> > fluid. DOT 3 brake fluids are mixtures of glycols and glycol ethers. DOT 4
>> > contains borate esters in addition to what is contained in DOT 3. These
>> > brake fluids are somewhat similar to automotive anti-freeze (ethylene
>> > glycol) and are not, as Dr. Curve implies, a petroleum fluid. DOT 5 is
>> > silicone chemistry. 
>> > Fluid Compatibility 
>> > Brake system materials must be compatible with the system fluid.
>> > Compatibility is determined by chemistry, and no amount of advertising,
>> > wishful thinking or rationalizing can change the science of chemical
>> > compatibility. Both DOT 3-4 and DOT 5 fluids are compatible with most brake
>> > system materials except in the case some silicone rubber external components
>> > such as caliper piston boots, which are attacked by silicon fluids and
>> > greases. 
>> > Water absorption and corrosion 
>> > The big bugaboo with DOT 3-4 fluids always cited by silicone fluid advocates
>> > is water absorption. DOT 3-4 glycol based fluids, just like ethylene glycol
>> > antifreezes, are readily miscible with water. Long term brake system water
>> > content tends to reach a maximum of about 3%, which is readily handled by
>> > the corrosion inhibitors in the brake fluid formulation. Since the
>> > inhibitors are gradually depleted as they do their job, glycol brake fluid,
>> > just like anti-freeze, needs to be changed periodically. Follow BMW's
>> > recommendations. DOT 5 fluids, not being water miscible, must rely on the
>> > silicone (with some corrosion inhibitors) as a barrier film to control
>> > corrosion. Water is not absorbed by silicone as in the case of DOT 3-4
>> > fluids, and will remain as a separate globule sinking to the lowest point in
>> > the brake system, since it is more dense. 
>> > Fluid boiling point 
>> > DOT 4 glycol based fluid has a higher boiling point (446F) than DOT 3 (401F)
>> > and both fluids will exhibit a reduced boiling point as water content
>> > increases. DOT 5 in its pure state offers a higher boiling point (500F)
>> > however if water got into the system, and a big globule found its way into a
>> > caliper, the water would start to boil at 212F causing a vapor lock
>> > condition [possible brake failure -Ed.]. By contrast, DOT 3 fluid with 3%
>> > water content would still exhibit a boiling point of 300F. Silicone fluids
>> > also exhibit a 3 times greater propensity to dissolve air and other gasses
>> > which can lead to a "spongy pedal" and reduced braking at high altitudes. 
>> > DOT 3 and DOT 4 fluids are mutually compatible, the major disadvantage of
>> > such a mix being a lowered boiling point. In an emergency, it'll do.
>> > Silicone fluid will not mix, but will float on top. From a lubricity
>> > standpoint, neither fluids are outstanding, though silicones will exhibit a
>> > more stable viscosity index in extreme temperatures, which is why the US
>> > Army likes silicone fluids. Since few of us ride at temperatures very much
>> > below freezing, let alone at 40 below zero, silicone's low temperature
>> > advantage won't be apparent. Neither fluids will reduce stopping distances. 
>> > With the advent of ABS systems, the limitations of existing brake fluids
>> > have been recognized and the brake fluid manufacturers have been working on
>> > formulations with enhanced properties. However, the chosen direction has not
>> > been silicone. The only major user of silicone is the US Army. It has
>> > recently asked the SAE about a procedure for converting from silicon back to
>> > DOT 3-4. If they ever decide to switch, silicone brake fluid will go the way
>> > of leaded gas. 
>> > Brake system contamination 
>> > The single most common brake system failure caused by a contaminant is
>> > swelling of the rubber components (piston seals etc.) due to the
>> > introduction of petroleum based products (motor oil, power steering fluid,
>> > mineral oil etc.) A small amount is enough to do major damage. Flushing with
>> > mineral spirits is enough to cause a complete system failure in a short time
>> > I suspect this is what has happened when some BMW owners changed to DOT 5
>> > (and then assumed that silicone caused the problem). Flushing with alcohol
>> > also causes problems. BMW brake systems should be flushed only with DOT 3 or
>> > 4. 
>> > If silicone is introduced into an older brake system, the silicone will
>> > latch unto the sludge generated by gradual component deterioration and
>> > create a gelatin like goop which will attract more crud and eventually plug
>> > up metering orifices or cause pistons to stick. If you have already changed
>> > to DOT 5, don't compound your initial mistake and change back. Silicone is
>> > very tenacious stuff and you will never get it all out of your system. Just
>> > change the fluid regularly. For those who race using silicone fluid, I
>> > recommend that you crack the bleed screws before each racing session to
>> > insure that there is no water in the calipers. 
>> > New developments 
>> > Since DOT 4 fluids were developed, it was recognized that borate ester based
>> > fluids offered the potential for boiling points beyond the 446F requirement,
>> > thus came the Super DOT 4 fluids - some covered by the DOT 5.1 designation -
>> > which exhibit a minimum dry boiling point of 500F (same as silicone, but
>> > different chemistry). 
>> > Additionally, a new fluid type based on silicon ester chemistry (not the
>> > same as silicon) has been developed that exhibits a minimum dry boiling
>> > point of 590F. It is miscible with DOT 3-4 fluids but has yet to see
>> > commercial usage. 
>> > 
>> > 
>> > 
>> >                
>> > Herb 
>> > 
>> > 1956 Plymouth Belvedere 361 4-Sale 
>> > 1959 Coronet 326 Poly 
>> > 1961 Belvedere Custom Suburban 318 Poly 
>> > 1962 Dodge Dart 225 Slant Six 4-Sale 
>> > 1963 Fury 2D/HT 6.1L 
>> > 1963 Sport Fury Convertible 361 
>> > 1970 Chrysler 300 Hurst 440 
>> > 1999 Durango SLT 5.9L 
>> > 2008 SRT-8 Magnum 6.1L 
>> > St. Louis, MO.
>> > 
>> > [Non-text portions of this message have been removed]
>> > 
>> > 
>> 
>> [Non-text portions of this message have been removed]
>> 
>> 
> 


[Non-text portions of this message have been removed]



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