How often does the brake fluid need changing?

Joe_Horner

Excellent description of the colours, GB!

Although, wonder how many readers are now going to get their collars felt on suspicion of drunk-in-charge as they lean under their bonnets with a bottle of vermouth in one hand and a fine malt in t'other

As for brake fluid, absolutely agree. Change on condition to avoid a very slight risk of boiling (potentially nasty) and a much bigger risk of rust (potentially expensive).

Apart from the colour, you can get electrical testers for about £15 but they're not 100% reliable (they can fail new fluid from a sealed bottle sometimes) or, if your wife is understanding, get a BBQ thermometer (about a fiver), pull some from the reservoir, and boil it up on the stove to measure the boiling point directly. Not as accurate as a proper lab test, but close enough if you're worried about such things.

For DOT4 anything below about 175 degrees is getting to change time.

Richard53

oscarward wrote: »

e.g. Peugeot 407 coupe was told it needed the ABS/Brake limiter etc gubbins activating by computer to ensure complete change.

This is getting more common. The vehicle needs to be plugged into the diagnostic computer so that various valves etc can be opened before the system can be bled through. Whether it is a technical necessity or just a way of making the poor bloody motorist visit the dealership more often is not clear.

BMW bikes are like this now, one of the reasons I got rid of mine. I like to change the fluid every two years as a matter of course. On a bike, it's a £10, 20-minute job - IF the system is kept simple. I now avoid ABS on motorcycles as far as possible, for this reason.

By the way, if anyone is messing about with brake fluid, don't forget that the modern stuff is highly flammable.

Joe_Horner

Richard53 wrote: »

By the way, if anyone is messing about with brake fluid, don't forget that the modern stuff is highly flammable.

Good point - it's easy to forget the things that are second nature. It's not advisable to use a gas hob (or smoke during) boiling tests :beer:

neil_999

I have owned 32 cars now - I've changed brake fluid once, BUT only because it was green (so I suspected it was 22yrs old) and it still didn't affect performance. 2 years just seems farcical to me. I know about water contamination but in 2 years?

I will put my neck on it here and would say once ever 100,000 miles would be more than fine...let the bashings commence!!

reeac

neil_999 wrote: »

I have owned 32 cars now - I've changed brake fluid once, BUT only because it was green (so I suspected it was 22yrs old) and it still didn't affect performance. 2 years just seems farcical to me. I know about water contamination but in 2 years?

I will put my neck on it here and would say once ever 100,000 miles would be more than fine...let the bashings commence!!

With that many cars it sounds as if you change the whole car rather than the brake fluid. Just the latter would be cheaper.

mrsmortenharket

Thank you all

Have decided not to get the brake fluid & air con done.

Lisa

Joe_Horner

mrsmortenharket wrote: »

Thank you all

Have decided not to get the brake fluid & air con done.

Lisa

Didn't like to say before because it was your decision and after a while you get tired of the shouts of "but it's SAFETY, won't somebody think of the children?" when certain parts of cars are discussed.

But, honestly, from an MSE perspective that's probably the right decision. The only time (in over 27 years of home maintenance) that I've ever changed brake fluid is when I've been replacing something that means bleeding the system through anyway.

Despite that, I haven't suffered brake failure and crashed yet

Paperbird

A firm pedal and no brakes is due to brake fade, it's rare with disc brakes but common on older cars with drum brakes and nothing to do with the fluid.
When the brake fluid boils the pedal will go to the floor. This has happened to me and I now change the fluid every 5 years.
Air con only needs regassing when you notice it's not as cold as it used to be.
Coolant on most cars lasts 5 years and needs changing not because it no longer protects from freezing but because it looses it's anti corrosion properties.

facade

Paperbird wrote: »

Coolant on most cars lasts 5 years and needs changing not because it no longer protects from freezing but because it looses it's anti corrosion properties.

5 years is for OAT- Organic Acid Technology, usually red.

The ethylene glycol (blue/green) only lasts 2 years.

The Evans waterless coolants last for life, there will be a sticker near the radiator warning not to add water.

Joe_Horner

Paperbird wrote: »

When the brake fluid boils the pedal will go to the floor. This has happened to me and I now change the fluid every 5 years.

Even with contaminated fluid, unless you drive very heavily on the brakes (like, track day style), boiling is generally caused by a partially seized wheel cylinder or caliper allowing heat to build up continually even when you're not using the brakes.

DOT 4 fluid has a "wet" boiling point of 155 degrees C, which is a very hot braking system for normal road use!