G4VHD

http://www.bimmerdiy.com/dir/

There is a degree of confusion regarding the specification of brake fluid and this article sets out 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 which are important. All currently available brake fluids are covered by one of the following specifications; DOT3, DOT4, DOT5 and DOT5.1. The laws of thermo-dynamics dictate that the energy from motion is turned into heat through friction. A braking system only works efficiently if the fluid remains incompressible. If the brake 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 be absorbed by the fluid. The effect is to reduce the boiling point of the fluid, which reduces the efficiency 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 glycol compounds. * DOT 5, which are based on Silicone. Note the two types of fluid are not compatible and must not be mixed in a braking system. SILICONE BRAKE FLUID (DOT 5) Silicone based DOT 5 was originally introduced to give higher temperature performance over glycol DOT 4. Silicone fluid also has other advantages, it does not damage paintwork and it does not absorb water. However, silicone fluid is a poor lubricant and does not lubricate ABS pumps as well as PAG fluids. 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 low spots in the system and cause corrosion. This water can vaporise when heated under heavy braking 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 the specification 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 has a similar spec to DOT4 for the boiling point (>260) but is a lot lower viscosity @-40C typically 900 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 DOT level. 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 boiling point. Normal Dot4 is >260C whilst Super DOT 4 is more like >310C

Please ignore Andy and my imaturaty :D

Oh but I did....so funny, I was hoping I'd at least have time to save me 2's and 1's to make £20 :lol:

:lol:

arrgh how do I unlock it lol....andy..not funny, but clever lol

Ill give £20 to the last person to post on this thread :lol:

Manure

I got a feeling were going to get on quite well :rolleyes:

bacteria burgers lol

Yeah Santa Pod, Andys sorting it out, 3L M sport wold be nice to have there

Welcome along mate, Shame about you knowing Andy :rolleyes: bad luck Cant wait to see the pics....you going to be at the show?

Hound... :rolleyes:

To be honest I must agree. As I drive through one of the busiest parts of any motorway in the UK each day I see some proper T###s The worst...undertaking, in the hard shoulder, doing around 90!!!!! To be honest I was hoping he wraped him self round a lamp post on the slip road.

He'd da man.... :lol:

This man is my hero, loads more where this came from

Check this crazy dude out

Yeah pics, the neighbors think im mad, I take before, during and after pics on everything i do, car or not... Im a freak I know :blink:

Not a service, but brought parking brake cables today, will be doing them Saturday as im fed up of it now holding on the drive. So that will be a little bit of satisfaction. Ill do pics too

Request sent....

Foot

Haha funny as

Lol its a mistake.... If your interested get in there quick mate

Nice on, glad its all sorted mucka