Óleo para travões. Para vocês qual o melhor D.O.T.4?

[dasthunder]

Boas gostaria de arranjar um bom óleo de travões DOT4. Qual o que me aconselham que possa evitar ao máximo a fadiga em travagens?
Onde posso arranjar esse óleo (zona de Lisboa)?

Obrigado

[Illusion]

Por exemplo

CASTROL REACT PERFORMANCE DOT 4 500Ml - TEXOLEO.com

http://www.opieoils.co.uk/pdfs/castr...ance-dot-4.pdf

[ChumLee]

Ferodo e AP Racing também são bons óleos

[nathaniel]

que óleo é indicado para aqui?

[CL]

Muito estranha essa indicação... porque o DOT 5 é um fluido muito especial à base de silicone, que não é miscível nem pode ser utilizado directamente (sem limpezas e trocas de vedantes, etc.) em sistemas que funcionaram anteriormente com os DOT 4 ou 5.1.

O DOT 3 é uma classificação já muito antiga e francamente de pior qualidade que o DOT 4 que se encontra facilmente à venda em qualquer lado.

Já viste se o manual do carro diz mais alguma coisa sobre o fluido de travões?

Quanto a marcas, todas as mais conhecidas são boas... Castrol, Ferodo, AP, etc.

[MadDragon]

DOT 5 não podes usar, como disse o CL, é à base de silicone.
Podes usar o DOT 3, o 4 e o 5.1.

Para não haverem confusões, eu optaria pelo DOT 4.
O DOT 3 e 4 são semelhantes.
A unica diferença está na temperatura de fervura e provavelmente na higropicidade.

[adenilson707]

Marcas de fluido de freio, que eu conheço, de boa qualidade é Varga/TRW, Bosch e Motul.

Parte logo para o DOT 5.1

[nto]

Marcas de fluido de freio, que eu conheço, de boa qualidade é Varga/TRW, Bosch e Motul.

Parte logo para o DOT 5.1

Não precisa de ír directamente para o DOT 5.1

No tópico dos óleos, já foi referido que até há DOT com melhores características que os DOT 5.1, ou seja, os SUPER DOT 4.

Basicamente e em regra, subindo sempre em qualidade é:

- DOT 4

- DOT 5.1

- SUPER DOT 4




Já agora:

Brake fluid... Bit of a mystery topic

To help dispel some myths and for some good solid general info on the mysterious world ofbrake fluids I decided to contact Millers Oils up in West Yorkshire.

Their Technical Director, Martyn Mann was on hand to give us some useful info… below isMartyn's article on brake fluids.
There is a degree of confusion regarding the specification of brake fluid and this article setsout to clarify the situation.

The Department of Transportation (DOT) classifies brake fluids to defined specifications.

These specifications relate to their boiling points and chemical composition, both of whichare important. All currently available brake fluids are covered by one of the followingspecifications; DOT3, DOT4, DOT5 and DOT5.1.

The laws of thermo-dynamics dictate that the energy from motion is turned into heat throughfriction. A braking system only works efficiently if the fluid remains incompressible. If thebrake fluid boils, it turns to gas, which is compressible and the braking system becomes“spongy” or in extreme cases fails completely.

A brake system is not perfectly sealed and moisture can get into the system and beabsorbed by the fluid. The effect is to reduce the boiling point of the fluid, which reduces theefficiency of the braking system, as described above.

The DOT specifies two reference tests for brake fluids.

* Dry boiling point - the boiling point of fresh fluid* Wet boiling point –the boiling point once the fluid has absorbed moisture(representing brake fluid after time spent in a real situation).

There are two main types of brake fluids:

* DOT 3, DOT 4, Super DOT4* and DOT 5.1 which are based on poly glycolcompounds.
* DOT 5, which are based on Silicone.

Note the two types of fluid are not compatible and must not be mixed ina braking system.

SILICONE BRAKE FLUID (DOT 5)

Silicone based DOT 5 was originally introduced to give higher temperature performance overglycol DOT 4. Silicone fluid also has other advantages, it does not damage paintwork and itdoes not absorb water.

However, silicone fluid is a poor lubricant and does not lubricate ABS pumps as well as PAGfluids. It is also more compressible than PAG fluids, which can result in a sluggish or spongy pedal. It therefore requires special design considerations in braking systems. Further,because it does not absorb water, any water remains as globules, which can pool in lowspots in the system and cause corrosion. This water can vaporise when heated under heavybraking giving a disastrous effect on braking efficiency.

DOT5 fluids are not recommended for motor sport applications.

POLY GLYCOL BRAKE FLUIDS (DOT 3, 4 AND 5.1)

Glycol based DOT 4 fluid is the current mainstream brake fluid, and you will see that thespecification is considerably better than DOT 3 which it replaces.

DOT 5.1 has higher specification still and is for fast road and occasional track day use. It hasa similar spec to DOT4 for the
boiling point (>260) but is a lot lower viscosity @-40C typically900 centistokes (compared to 1500 - 1800 centistokes for DOT 4 and super DOT 4).

Listed in the table below, are the minimum dry/wet boiling point specifications for each DOTlevel.

BOILING POINT:

DOT 3 - 205°C (dry) / 140°C (wet)
DOT 4 - 230°C (dry) / 155°C (wet)
DOT 5 (silicone) - 260°C (dry) / 185°C (wet)
DOT 5.1 (PAG) - 260°C (dry) / 185°C (wet)
Super Dot4 * - 300°C (dry) / 195°C (wet)(racing brake fluid)

* Super DOT4: The main difference between DOT 4 and Super DOT 4 is the dry boilingpoint. Normal Dot4 is >260C whilst Super DOT 4 is more like >310C

With thanks to Martyn Mann - Technical Director Millers Oils.

in: http://www.opieoils.co.uk/pdfs/tech-...-Explained.pdf

in: http://forum.autohoje.com/boxes/335-...post1066921938

[nto]

Para ficar com outra ideia:






in: http://www.exx.se/techinfo/brake_fluid/index.html

in: http://forum.autohoje.com/boxes/335-...post1066921948

[nto]

Ainda:

What do you think is most important when choosing a brake fluid?


Most drivers today are concerned about the boiling temperature of their brake fluid, and not too concerned if it meets DOT specifications or not.
This is ok for drivers who only use their cars at the race circuit. Ordinary drivers who frequently drive their cars on ordinary streets should be more concerned if their fluid meets DOT specification. Brake fluid that do not meet DOT specification can speed up the deterioration of brake components over a extended period time. It can also lead to the malfunctioning of ABS during cold weather. Most people do not know much about brake fluid, and it can be hard to find relevant information to learn more about it.
Please read the following section, 'Understanding Brake Fluids' is an easy to understand guide explaining brake fluid.


What is DOT specification?


DOT is the abbreviation for the 'Department of Transportation', which is an American government transportation department. The DOT set standards such as FMVSS (Federal Motor Vehicle Safety Standard) very similar to the JIS in Japan or DIN in Germany. The following table shows the DOT brake fluid specifications:

DOT 3	Glycol	over 205℃	over 140℃	over 1.5cst	under 1500cst	7.0-11.5
DOT 4	Glycol	over 230℃	over 155℃	over1.5cst	under 1800cst	7.0-11.5
DOT 5.1	Glycol	over 260℃	over 180℃	over 1.5cst	under 900cst	7.0-11.5
DOT 5	Silicon	over 260℃	over 180℃	over 1.5cst	under 900cst	7.0-11.5

• □ Dry Boiling Temp. : Boiling point when the fluid is brand new, no moisture absorption.
• □ Wet Boiling Temp. : Boiling point with fluid that has 3.7% water by volume. After 1-2 years of fluid use.
• □ Viscosity : a measure to represent the brake fluid flow property. Higher the value, the more difficult for the fluid to flow. If the value is high when the air temperature is low, 　the fluid can have a negative effect on ABS performance.
• □ pH value : value to show acidity / basicity of a solution. If the pH value is lower than 7.0 (strong acidity), the fluid can accelerate corrosion of other brake components

What is boiling point temperature?


The temperature at which the fluid boils. Water boils at 100℃、where as brake fluid with high boiling point will boil around 300℃, and low boiling point brake fluid will boil around 140℃.


Why is a low boiling point temperature not acceptable?


When driving aggressively on windy mountain roads or race circuits, brake pad can reach over 300℃. This high heat gets passed onto the brake fluid through the calipers, which can raise the fluid temperature over 200℃. If the brake fluid is repeatedly heated past it's boiling point, some of the fluid vaporizes and creates bubbles within the brake lines. This is a very dangerous situation since this can lead what is commonly know as vapour lock, or simply the brakes not working. This occurs since the vapour is compressed instead of the fluid so the brake pads do not move.


What is percent water by volume?


The most common ingredient of brake fluid is glycol-ether. This fluid is hygroscopic which mean it absorbs moisture from the atmosphere. The 'percent by volume' is a measure of the water content in the brake fluid.


The higher the DOT number, the higher the brake fluid performance ?


This is not exactly correct. The DOT numbers categorizes the fluids by various uses.

Cars with small to medium sized engines

Cars with larger sized engine and/or for use with sports driving

Cars with larger sized engine and/or for use with sports driving Cars with larger sized engine and/or for use with sports driving (Cold climate regions)

Main ingredient is Silicon, Special application cars (Hummer, Harley-Davidson)

Major difference
DOT3 vs DOT4 - Boiling point temperature

DOT4 vs DOT5.1 - Boiling point temperature & viscosity at low temperatures


DOT 5.1 has strict viscosity standards at lower temperature in addition to having a high boiling point temperature. Therefore, in cold climate areas, the DOT 5.1 brake fluid is very commonly used on most cars. The most widely distributed brake fluid is the DOT 4, which has a dry boiling point temperature around 270℃ and a wet boiling point temperature around 170℃.The boiling point temperatures of DOT4 is very similar to those of DOT5.1. The major difference is the viscosity at low temperatures.

Today, cars are commonly equipped with ABS, and DOT5.1 fluid is used since the viscosity of it helps the ABS work consistently even in cold climates.


Which DOT specification is best for race circuit use?


Most racing brake fluids are developed for circuit-use only. The boiling point temperatures easily exceeds DOT5.1 specification but the viscosity and pH levels do not pass DOT5.1 specification. This is why racing brake fluid do not pass DOT 5.1 specification.


Why do most of racing fluid not exceed DOT specification?


The answer is simple. The technical difficulties to develop such a product will significantly increase cost. To develop a brake fluid with DOT4 spec viscosity, pH level higher than 7.0, and dry boiling point temperature above 320℃ can be very difficult, which would significantly increase production cost.


Is it safe to use racing brake fluid for street-use?


The use of racing brake fluid that exceeds DOT specification is safe for street-use. The use of racing brake fluid that do not meet DOT specification can speed up the deterioration of brake components over a extended period time. It can also lead to the malfunctioning of ABS during cold weather.


Which DOT spec should be used for circuit trials?


There are no problems with using racing brake fluid, if you are going to change fluids from circuit-use to street-use. For drivers who do not want to change brake fluids between the two uses, we recommend the use of racing brake fluid that meet DOT specification, DOT5.1 or super DOT4 brake fluid.


How frequently should brake fluid be replaced?


For everyday drivers, who use brake fluid that exceed DOT4 specification, fluid replacement once 2 years is acceptable. For people who use DOT3 fluid, fluid replacement every year is recommended. For people who drive aggressively on winding roads, fluid replacement every six month to a year is recommended. For people who drive their cars on the race circuit, replacement before each event is recommended.


What is Super DOT4?


Meet DOT5.1 boiling temp. specification but, low temp. viscosity characteristics is DOT4.


Is soft viscosity at low temp. such as DOT5.1 makes soft pedal touch feel at circuit ?


No, low temp. viscosity may soft but, will not soften pedal touch at circuit. The fluid temp. during circuit run become over 150℃ and viscosity characteristics at the temp.
range has no major difference from other grades. Also, there is no major interrelationship between fluid's adhesive (viscosity) and pedal touch.
The pedal touch depend on the moisture absorbed and lower the moisture volume more solid touch and higher the moisture volume softer (sponge like) touch.


Is it safe to mix old and new fluid ? Or, is mix of different grade fluid ?


Basically, not recommended.
If either fluid as glycol base and both passed DOT approved, no major functional problem. However, in performance-wise not become a average of 2 but, lower side kept.
Therefore, refrain from mixture of fluid but, replacement of whole volume is recommended.


What could be the volume required for replacement ?


For passenger cars, it generally requires 800ml ~ 1L for full volume replacement. (Trucks / Lorries are not in this category)
For partial replacement on Caliper portion alone, it is possible by 300~400ml

in: Brake Literature^Understanding Brake FluidsbDIXCEL

in: http://forum.autohoje.com/boxes/335-...post1066921958

[adenilson707]

Não precisa de ír directamente para o DOT 5.1

No tópico dos óleos, já foi referido que até há DOT com melhores características que os DOT 5.1, ou seja, os SUPER DOT 4.

Basicamente e em regra, subindo sempre em qualidade é:

- DOT 4

- DOT 5.1

- SUPER DOT 4




Já agora:





in: http://forum.autohoje.com/boxes/335-...post1066921938

Aqui NUNCA vi vender Super DOT 4.

O máximo só DOT 5.1

O meu é DOT 4 e vou partir pra ignorância.

Já está comprado um litro de fluido de freio DOT 5.1
Só vou levar numa oficina e trocar. Sorte que eles fazem a substituição via máquina, e não bombeando o pedal do freio.

[draper]

... pensava que o tópico dos óleos também era para óleo de travões...