EV cars brake fluid

[Pica-Pica]

E-bmw said:

vw_99 said:

Sorry my theory.
If EVs are not using brakes as much n fluid stays "still" also no clutch to help move it around either.

Whether the fluid is stationary or moving does not change its properties or the amount of water it absorbs.

This. It doesn’t matter whether EV or ICE, the service period will be time-based.

[stevieturbo]

vw_99 said:

But if the fluids getting moved through tha system not just sat in tank would that not help reduce the amount of moisture it absorbs?

Not argueing just wounderning.

It doesn't really move much at all, ever anyway.

And the lid/system to some degree is closed to atmosphere, so doesn't have a lot of exposure to atmos. It's not totally sealed, but it also doesn't have huge gaping holes either

[vw_99]

Other point i was asking earlier. Or trying too maybe.
Why has brake fluid not moved on like oils where they can last longer before a change. I know some cars need oil changed before sechdule.

But why has brake fluid not been "evolved" to not take in water

[stevieturbo]

vw_99 said:

Other point i was asking earlier. Or trying too maybe.
Why has brake fluid not moved on like oils where they can last longer before a change. I know some cars need oil changed before sechdule.

But why has brake fluid not been "evolved" to not take in water

Oil still needs changed regularly.

Oil needs changed far more often than brake fluid.

And regardless of when brake fluid should be changed, most garages never do it anyway...so brake fluid lasts longer than lots of things.

There really is no problem at all with current brake fluids.

It's a bit like, why have cars not evolved not to corrode ? Yet they still do

[b0rk]

Maybe in the future electromechanical braking systems will supplant hydraulics. It’s one of those bits of tech that has been nearly ready for a long time..

[GreenV8S]

vw_99 said:

But why has brake fluid not been "evolved" to not take in water

Silicon based brake fluid doesn't take in water. That's a disadvantage. Water enters the system through hoses, seals and the vent in the reservoir. Glycol based fluid absorbs the water and so it needs to be replaced periodically. When you replace the fluid, the old fluid takes all the contaminants with it. Silicon based fluid doesn't absorb the water. That means it lasts much longer than the glycol based fluid. It also means it's much harder to remove the water and contamination, because it is not disolved in the fluid and may not be carried out with it.

[hidetheelephants]

darreni said:

Ev’s also rend to be heavier so more demanding on brakes.
We had an e power qashqai for the last month & the brakes front & rear are huge as I suppose they would need to be when repeatedly stopping 2 tons.

Have you ever driven an EV? Unless driven like it's stolen very little brake use, mostly when coming to a halt. Another nonsense thread filled with EV FUD.

[stevieturbo]

hidetheelephants said:

Have you ever driven an EV? Unless driven like it's stolen very little brake use, mostly when coming to a halt. Another nonsense thread filled with EV FUD.

Manufacturers need to fit suitable brakes, they cannot hope or assume everyone will drive like Miss Daisy everywhere. They are big, they are very heavy, they absolutely should have good brakes

Let's face it, many modern cars have huge brakes compared to cars of yesteryear

[thebraketester]

stevieturbo said:

hidetheelephants said:

Have you ever driven an EV? Unless driven like it's stolen very little brake use, mostly when coming to a halt. Another nonsense thread filled with EV FUD.

Manufacturers need to fit suitable brakes, they cannot hope or assume everyone will drive like Miss Daisy everywhere. They are big, they are very heavy, they absolutely should have good brakes

Let's face it, many modern cars have huge brakes compared to cars of yesteryear

More nonsense.

[TwinKam]

vw_99 said:

Other point i was asking earlier. Or trying too maybe.
Why has brake fluid not moved on like oils where they can last longer before a change. I know some cars need oil changed before sechdule.

But why has brake fluid not been "evolved" to not take in water

Because it has been deliberately evolved to take in water. Yes, you read that right.
You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.

[stevieturbo]

thebraketester said:

More nonsense.

you do indeed spout it

[Evanivitch]

stevieturbo said:

Manufacturers need to fit suitable brakes, they cannot hope or assume everyone will drive like Miss Daisy everywhere. They are big, they are very heavy, they absolutely should have good brakes

Let's face it, many modern cars have huge brakes compared to cars of yesteryear

There's not a car today that is fitted with friction brakes that will not over-brake the tyre grip in an emergency stop.

Larger brakes on performance cars are for thermal management, they are far in excess of what is required on the road.

Hence why VW have revived the drum brake and more Will follow.

[Megaflow]

Mr E said:

Rough101 said:

Just flush every 2 years like ICE cars.

How many people do you think actually do that?

Not many, because as Max Torque used to point out when this debate has come up in the past, the climate in this country means that moisture build up in brake fluid is very minimal to non existent. That is back up by the number of years I have been testing my brake fluid for and never got a reading above 1%.

[Evanivitch]

TwinKam said:

Because it has been deliberately evolved to take in water. Yes, you read that right.
You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.

If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?

[GreenV8S]

Evanivitch said:

If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?

As well as having water disolved into it, brake fluid is also absorbing particulates and being denatured by heat in the calipers. If you ever cook your brakes the fluid in the calipers will be nasty stuff while the fluid in the reservoir still looks new.

[stevieturbo]

Evanivitch said:

If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?

A reservoir change is about as much use as a politician

[Super Sonic]

thebraketester said:

More nonsense.

Not gonna tell you why though, just gonna make an assertion with zero evidence to back it up.

[TwinKam]

Evanivitch said:

TwinKam said:

Because it has been deliberately evolved to take in water. Yes, you read that right.
You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.

If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?

Because the reservoir fluid doesn't actually do anything, it's just spare fluid, it doesn't get used until it leaves the reservoir, by which time you can only remove it by drawing it out at the far (nipple) ends.
Do yourself a favour and do a full change, starting by sucking as much as you can from the reservoir, refilling with fresh, then bleeding say 100 to 150ml from each corner in turn into a see-through container. Hold it up to the light each time. Now go round again and look at the four samples again. You'll be pleased that litre is out.
NB. Use a look-up to ensure that you use the correct type fluid, most modern cars use a lower viscosity type because of ESP, I've found few people that are aware of this.

[Pica-Pica]

TwinKam said:

Evanivitch said:

TwinKam said:

Because it has been deliberately evolved to take in water. Yes, you read that right.
You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.

If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?

Because the reservoir fluid doesn't actually do anything, it's just spare fluid, it doesn't get used until it leaves the reservoir, by which time you can only remove it by drawing it out at the far (nipple) ends.
Do yourself a favour and do a full change, starting by sucking as much as you can from the reservoir, refilling with fresh, then bleeding say 100 to 150ml from each corner in turn into a see-through container. Hold it up to the light each time. Now go round again and look at the four samples again. You'll be pleased that litre is out.
NB. Use a look-up to ensure that you use the correct type fluid, most modern cars use a lower viscosity type because of ESP, I've found few people that are aware of this.

A litre? More like 500ml.

[Evanivitch]

TwinKam said:

Evanivitch said:

TwinKam said:

Because it has been deliberately evolved to take in water. Yes, you read that right.
You do not want little puddles of water sitting in all the low points in the lines, developing internal rust spots. You want any moisture to be 100% homogenised (absorbed) into the brake fluid so that, as others have said, it will all be removed along with the fluid when it is flushed. Inasmuch, brake fluid should be considered a 'consumable'; it deteriorates by design during its useful life of two to three years because it changes from being pure brake fluid into a fluid that contains moisture and rubber seal debris etc.
With my brake fluid tester, which is in daily use, I can clearly see from its 'traffic lights' the water content/contamination rising progressively from 0% in Y0 when the fluid was changed, through Y1, Y2, and generally is maxed out (showing a red light) by Y3. No difference on Hybrids or EVs.

If this is entirely true that it is fully homogenised, why ever do a full fluid change? Why not partial reservoir changes annually or more often?

Because the reservoir fluid doesn't actually do anything, it's just spare fluid, it doesn't get used until it leaves the reservoir, by which time you can only remove it by drawing it out at the far (nipple) ends.
Do yourself a favour and do a full change, starting by sucking as much as you can from the reservoir, refilling with fresh, then bleeding say 100 to 150ml from each corner in turn into a see-through container. Hold it up to the light each time. Now go round again and look at the four samples again. You'll be pleased that litre is out.
NB. Use a look-up to ensure that you use the correct type fluid, most modern cars use a lower viscosity type because of ESP, I've found few people that are aware of this.

So when you're using your brake fluid tester, where are you taking the sample from? All four corners? I thought it was typically just done at the reservoir.

I'm just talking daily drivers, I wouldn't suggest cutting corners on performance or track vehicles.