Curiozitate legata de lichidul de frana!!

salut...cine poate sa ma lamureasca si pe mine: care e diferenta intre lichidul de frana DOT3 si cel DOT4

dot 4 este recomandat si la vectra mea si eu nu am abs.
nici eu nu stiu diferentele intre ele, dar daca tot m-ai facut curios, uite ce am gasit
D.O.T ratings

All brake fluids are DOT rated. Your owners handbook for your car or motorbike probably tells you to use DOT3 or DOT4 from a sealed container. The DOT ratings are a set of minimum standards the fluid must adhere to in order to get the rating, and thus work in your braking system. The following table shows the various properties of DOT ratings. Remember that the values here are the minimum values. Most manufacturers make sure their product far exceeds minimum ratings.

Boiling Point DOT 3 DOT 4 DOT 5 (silicone-based) DOT 5.1 (non-silicone based)
Dry 401°F 446°F 500°F 500°F
Wet 284°F 311°F 365°F 365°F


The "dry" and "wet" boiling points in the table above are for brake fluid which is fresh from the bottle (dry) and which has a 10% water content (wet). A DOT study in 2000 discovered that on average, the brake fluid in a vehicle absorbs about 2% water every 12 months.
The two types of brake fluids shown in the table are DOT3/DOT4/DOT5.1 which are glycol (Polyalkylene Glycol Ether) based, and DOT5 which is silicone based. DOT3 and DOT4 fluids are interchangeable* - the only real difference is their boiling point. Theoretically you could interchange DOT4 and DOT5.1 fluids too but I wouldn't recommend it. DOT3/4/5.1 and DOT5 fluids cannot be mixed or interchanged under any circumstances. They mix like oil and water (ie. they don't) and the silicon based fluids can destroy the seals in brake systems which rely on the moisturiser additives that are present in DOT3/4/5.1 fluids.
Other things you ought to know about silicone based fluids:
- they are resistant to absorbing water, which is why their wet boiling points are so high. Problem is that any water content eventually pools in the low spots of the brake system and causes rust.
- they don't strip paint.
- they are not compatible with most ABS system because they doesn't lubricate the ABS pump like a glycol based fluid.
- putting this fluid in systems which have had DOT3/4 fluid in will cause the seals in the caliper and master cylinders to malfunction. Which means they need replacing. Which is expensive.

Oh, and don't ask me why DOT5.1 is glycol and DOT5 is silicon based. It doesn't make and sense to me either.

* There has been some discussion as to the use of DOT4 fluid in Toyotas that recommend DOT3 fluid - apparently something in the Toyota braking system doesn't play well with DOT4 fluid, particularly the master brake cylinder seals. The discussion about this can be found in the archives at the UK Pruis yahoo group.

sursa: http://www.carbibles.com/brake_bible.html

el a avut timp poate.
dar de exemplu eu nu stiam.si poate nici altii.

Bre, mie mi-a placut al doilea post care contine raspunsul dupa 3 ani!



Ultima modificare facuta de biela-manivela la Mar 23 Sep, 2008 9:01 am

S-a documentat omul bine inainte sa raspunda, care e problema?
Oare chiar se mareste procentul de apa din lichidul de frana?

Desigur ca se mareste procentul de apa din lichid pe masura ce trece timpul. Din acest motiv si nu numai se modifica caracteristicile tehnice ale substantei si nu mai are aceiasi eficacitate franarea.
Cred ca numai daca se adauga apa in amestec deja vorbim de alt punct de firbere si puterea masinilor noastre nu mai poate fi stapanita.....