Re: [Chrysler300] DOT Choice

[George McKovich <george@xxxxxxxxxxxx>]

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]



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