[Rbrown]

I appreciate there are a few people on here who will never have a car for 3 years....

My car due brake fluid service at end of Feb. Is it just in my head, or do you feel your brakes being less "biter" than they were?

Sure I will see if there is a difference after the service......

[ukbeemerboy]

Originally Posted by Rbrown

I appreciate there are a few people on here who will never have a car for 3 years....

My car due brake fluid service at end of Feb. Is it just in my head, or do you feel your brakes being less "biter" than they were?

Sure I will see if there is a difference after the service......

The brake fluid is due 3 years from build, not registration so this needs to be remembered.

Having the brake fluid changed should have no effect on the feel of the brakes themselves.

[Rich76]

Originally Posted by ukbeemerboy

The brake fluid is due 3 years from build, not registration so this needs to be remembered.

Having the brake fluid changed should have no effect on the feel of the brakes themselves.

Not really true, as brake fluid is hydroscopic over time it will absorb moisture.
Make of car doesn’t really have an effect on it but most manufactures recommend a change at between 2 and 3 years and then every two years after.
Most manufacturers recommend that anything above 3% water content you want to be changing the fluid

Most people won’t notice the drop in quality of the fluid but it does drop off, the peddle will start to feel different as the water compress at a different rate to the fluid , but as this is over a period of time most people don’t notice it

[RoShambolt]

Isn't it to do with the fluid being hygroscopic and absorbing water over time, I guess having a brake fluid with no water in and therefore a higher boiling point would perform better under harder braking situations. I doubt you would notice much difference in most situations. Still better to get it done though.

[RoShambolt]

Originally Posted by Rich76

Not really true, as brake fluid is hydroscopic over time it will absorb moisture.
Make of car doesn’t really have an effect on it but most manufactures recommend a change at between 2 and 3 years and then every two years after.
Most manufacturers recommend that anything above 3% water content you want to be changing the fluid

Most people won’t notice the drop in quality of the fluid but it does drop off, the peddle will start to feel different as the water compress at a different rate to the fluid , but as this is over a period of time most people don’t notice it

Hydroscopic is to do with viewing items under water. Hygroscopic is to do with the ability of a substance to absorb water.

I'm not being a dick as I've only just found this out myself as I always thought it was hydroscopic too when talking about water in brake fluid.

[ukbeemerboy]

Originally Posted by Rich76

Not really true, as brake fluid is hydroscopic over time it will absorb moisture.
Make of car doesn’t really have an effect on it but most manufactures recommend a change at between 2 and 3 years and then every two years after.
Most manufacturers recommend that anything above 3% water content you want to be changing the fluid

Most people won’t notice the drop in quality of the fluid but it does drop off, the peddle will start to feel different as the water compress at a different rate to the fluid , but as this is over a period of time most people don’t notice it

If the OP’s brakes feel that much different after a brake fluid change then he either has an under lying issue, or the fluid hasn’t been changed for years. We know that’s not the case as the car is 3 years old as he states.

[Stainy]

Originally Posted by Rich76

Most people won’t notice the drop in quality of the fluid but it does drop off, the peddle will start to feel different as the water compress at a different rate to the fluid , but as this is over a period of time most people don’t notice it

/Pedant mode on...water doesn't compress - but it'll boil earlier than brake fluid and the steam does

[BBri89]

The only reason it should feel different (in normal driving) after a fluid change is if there is/was air in the system, either before or after the fluid change.

Old wet fluid shouldn't feel any different to new fresh dry fluid. Not under normal street driving.


Brake pads/discs on the other hand can make the pedal feel different.


They say to change brake fluid every 2 years (after the first change) but the fluid usually is still ok at that point, within acceptable % of water absorption.

[The0pportunist]

I did a brake fluid service a couple months ago at the dealer.

Absolutely no difference in the way brakes felt post service.

[Ennoch]

It shouldn't make any difference IMO until the fluid gets significantly older. The biggest damage to fluid, again IMO, comes from heat rather than age. And unless you're road rallying or doing trackdays modern car brakes simply don't get hot enough to boil fluid. Those who do experience 'fade' tend to find the pedal stays the same but the slowing effect lessens and that's a result of the brake pad friction material overheating rather than the fluid going. If you feel your pedal going long after repeated big stops then that'll be your fluid 'boiling' and the moisture in it becoming gas, which then compresses and gives you the long pedal. I'd replace it reasonably regularly but if it wasn't for trying to keep 'FSH' I wouldn't be doing it every two years on a stock car that isn't ragged. Even bike brakes which get relatively hotter much more regularly and have less fluid capacity still don't need bleeding that regularly for performance.

[Craig-SM]

I do my own brakes including fluid. Biggest difference comes from cleaning the calliper of all the built up dirt that prevents the pads and slides from moving as they should and wasting energy. This combined with new pads and discs properly bedding in makes them feel like new.
Having said that I change the brake fluid every 2 years on the cars and yearly on the bike. The fluid that comes out is always darker than what goes in. Not sure if this is from heat or the seals. An hours work and £10 worth of fluid it's no hardship.

[Techno 9000]

Originally Posted by Stainy

/Pedant mode on...water doesn't compress - but it'll boil earlier than brake fluid and the steam does

When I was 19 I had an experience of 'fluid fade'.
Driving down a very long hill (circa 3/4 mile) 30 limit in a town, nothing ahead of me, (foolishly) keeping my speed down all the way with the brakes. Traffic lights ahead at Red, that turned to Green as I approached, off the brakes, turned a bend in the road that levelled out and, at the next set of (Red) lights a couple of hundred yards further on, hit the brake pedal to find it went to the floor... Cue much pumping of the pedal to re-pressurise the system.

Haven't done that again in the next 30+ years I can tell you...

Under pressure the water doesn't boil easily, its when you come off the pedal that the water can be raised to boiling point, and the amount of 'slack' that needs taking up needs many presses of the pedal. If you're pushing on, you won't necessarily have the luxury of that time.

Agree that, in 'normal driving' / light use you don't feel any difference under foot.

[jackstrath]

I’m surprised no one has mentioned nipples yet

[Rbrown]

Originally Posted by jackstrath

I’m surprised no one has mentioned nipples yet

Very true - the jokes took longer than I thought.

Was expecting something like this....

"During lockdown I have developed a drink problem and I am now drinking brake fluid....but I know I can stop whenever I want......."

[330Stevie]

I boiled the brake fluid on one of my Alfa’s at a track day years back- then it feels different!!!!
Otherwise I’ve never really notice significant differences with stock fluid changes although I’m sure there maybe a small placebo effect to make us feel better when handing over money to get it done!
If there is a significant difference then I’d agree perhaps the fluid change has corrected something more than the fluid itself.....