What a marvellous help, many thanks I will investigate further.
One further question however - how do I flush the system?
Hi,
Forgive me for possible overkill..but I have found it always best to give a complete explanation than a short and sweet one.
Automobile hydraulics (clutch and brake) use special fluids. The different types are designated as DOT 3, DOT 4, DOT 5 and DOT 5.1. DOT 5 is silicone based and the rest are borate ester based. (The higher the number the higher the boiling point.) DOT 5 is NOT compatible with the others and switching to and from DOT 5 can cause grave problems. Avoid DOT 5 like the plague. However, once used, you must continue to do so. You cannot safely switch back without changing every bit of rubber in the system.
All brake fluids are designed to resist the absorption of water. That ability fades over time. Brake fluids (in clutch or brakes)should be changed once every 2-3 years depending on how damp your climate is.
Lorne
Hi Lorne, I apologise for this being my first post and don't want to appear to be coming on here waving a big stick at anyone.
I browsed through the rest of this topic briefly and found that no one picked up on a point you made about brake fluid being designed to resist water but this information is inaccurate.
All brake fluids discounting the silicone Dot 5 are Hydroscopic and absorb moisture from the atmosphere, When this happens, the moisture in the system can heat up and evaporate as we are continually using the brakes/clutch. The only thing left in the system to replace the evaporated moisture is air, as air is compressible, it renders the system inefficient and tell tail signs at the pedal indicate this. With a brake pedal, it becomes spongy, (with a servo assisted system, the spongy effect is only noticeable if the vacuum is exhausted) with a clutch, it effects smooth gear changing. Hydroscopic fluids also contaminate the system as moisture increases and begins to corrode the internal parts of the system. This is the reason we change the fluid in our systems periodically.
http://en.wikipedia.org/wiki/Brake_fluidPaul
