Brake fluid usage

[les0498]

Is anyone else’s Mg using a lot of brake fluid? I have topped mine up 4 times in 25,000 miles, it’s been in the garage but they say it just needed topped up. I have never had this with any other car but this is my first EV, is this normal?

 

[Ejaydee]

I would say no, because I have had two EV's (Zoe's) before getting my MG in May, and I never had to top up the brake fluid. Not had to do the MG4 either so far!

 

[omega22]

Likewise, never topped up in 18000 miles

 

[johnb80]

its normal for the fluid level to drop on any vehicle, as the pads / discs wear the pistons in the caliper need to be further out hence the fluid drop. That said, in an EV there shouldn't be much by way of brake wear if regen braking is used, it depends how much it's dropped over time. If there a leak in the brake pipes or callipers it should be evident by showing as a damp patch. The only other source of loss that's hidden is inside the brake servo (assuming the MG5 uses a servo and a vacuum pump)

 

[Lovemyev]

Is anyone else’s Mg using a lot of brake fluid? I have topped mine up 4 times in 25,000 miles, it’s been in the garage but they say it just needed topped up. I have never had this with any other car but this is my first EV, is this normal?

I would say, that unless you are riding the brake pedal or are a very heavy on your braking, then this is NOT normal at all !.
Regardless if it's an ICE or EV.
If excessive wear was the issue, then it would be clearly evident by a quick check of the amount of brake pad material that has been consumed already in the 25,000 miles covered.
As a very quick general guide, fluid can be required as the brake shoes / pads reduce in thickness due to wear.
As a result, the brake pistons now have a greater distance to travel.
This results in an extra displacement of fluid from the reservoir, therefore a small drop in the level.
If your brake pad wear is not excessive and level continues to drop, you have a leak !.
I can not see any other reason why fluid is needed.
I guess an important question maybe, just how much fluid have you been topping up the brake reservoir with ?.
Based purely on a personal basis of my type of driving style, I would NOT be expecting to top up my brake fluid at all in 25,000 miles TBH.

 

[Alb]

Unless you have significant brake wear you should be looking for a leak.

 

[Radders]

Is anyone else’s Mg using a lot of brake fluid? I have topped mine up 4 times in 25,000 miles, it’s been in the garage but they say it just needed topped up. I have never had this with any other car but this is my first EV, is this normal?

Took my mg es ev for its second year service, quoted £225. I asked why twice last years price, he replied the 'Chinese' suggest replacing the brake fluid.

why?,

the Chinese claim the fluid collects moisture from the air over time!

Hasn't it always? And won't the new fluid collect moisture?

Probably, shall we not do it then?

Ok.

Righto that'll be £106.

To be fair I know absolute zilch about cars, appears neither does the service manager

 

[Alb]

I specified the fluid change for my 2nd service and it cost £46.50+VAT.

 

[Moonraker244]

Took my mg es ev for its second year service, quoted £225. I asked why twice last years price, he replied the 'Chinese' suggest replacing the brake fluid.

why?,

the Chinese claim the fluid collects moisture from the air over time!

Hasn't it always? And won't the new fluid collect moisture?

Probably, shall we not do it then?

Ok.

Righto that'll be £106.

To be fair I know absolute zilch about cars, appears neither does the service manager

Because brake fluid attracts moisture it should be changed every 2 years. Otherwise you are inviting corrosion in the braking system and that is much more expensive to fix

 

[Radders]

Because brake fluid attracts moisture it should be changed every 2 years. Otherwise you are inviting corrosion in the braking system and that is much more expensive to fix

this is peculiar to ev's?

 

[Deep purple]

It is a biennial item in cars with ordinary brake fluid as the glycol based fluids are hygroscopic and the braking efficiency drops off with increased water content and also the components might corrode. If you want to avoid it you need to go for silicone brake fluid but this is only suitable for cars designed for it and so cant be used in most modern cars.

 

[Alb]

The principal concern comes from the fact that increasing water content lowers the temperature at which the fluid boils. This can lead to fade if the brakes get particularly hot and that's something you are more likely to find on a relatively heavy car such as an EV. One pragmatic workaround would be to test the fluid for water content during the service and make a renew or not decision based on the result.

 

[m4rmite]

Brake fluid testers can be bought cheaply.

Whether that would stop the changing of the fluid is a different matter, if it's a manufacturer requisition regardless of the reading.

 

[Radders]

I think I've already stated I know nothing about cars and evidently neither does the car dealers service manager. Again, is this peculiar to ev,s.

 

[m4rmite]

I think I've already stated I know nothing about cars and evidently neither does the car dealers service manager. Again, is this peculiar to ev,s.

It shouldn't be as ICE vehicles use DOT 3 or DOT4 - depending on model.

DOT 5 isn't used in systems with ABS

 

[SimonomiS]

The principal concern comes from the fact that increasing water content lowers the temperature at which the fluid boils. This can lead to fade if the brakes get particularly hot and that's something you are more likely to find on a relatively heavy car such as an EV. One pragmatic workaround would be to test the fluid for water content during the service and make a renew or not decision based on the result.

This is exactly what happened on my 2nd service. It was still OK so not changed

 

[Lovemyev]

This is exactly what happened on my 2nd service. It was still OK so not changed

Same here.
At the two year service it was NOT replaced, just the cabin filter and the routine health check.

 

[SimonomiS]

Same here.
At the two year service it was NOT replaced, just the cabin filter and the routine health check.

Exactly the same for me, SOH was at 100% though a few miles done since then...

 

[JimD]

I've had cars in my youth (when I did my own servicing) for donkeys years without having the brake fluid changed and didn't notice any problems. In fact all my mates who were also servicing their own cars weren't even aware of it as an issue.

I'm not saying it isn't a good idea, but I seriously doubt that there's much opportunity for water to get into the brake fluid under normal operating conditions.

 

[Lovemyev]

I think I've already stated I know nothing about cars and evidently neither does the car dealers service manager. Again, is this peculiar to ev,s.

No - It is not exclusive to EV's.
Time lines can vary with regards to brake fluid replacement.
The VAG group recommend replace at 3 years and every 2 years ongoing forward.
Brake fluid replacement on our previous Golf PHEV was about £60.00 at the main dealers.
That was about three years ago.
Honestly as others have said a much better and cost effective way, is to take a small sample of the fluid and then check for any presents of moisture contained in the fluid.
If so, THEN replace it !.
But this is a CHECK and therefore very little work content.
It's worth considering that EV's generally provide less work for the service depart over the ICE counter parts.
Therefore they are keeping very focussed on any work that can / will provide an income .
Pure guess, but I am willing to bet if you checked it with a detector, it is likely to be fine.
This being the case, then you can make the challenge - "Why are you changing the fluid ?".
Detector can be purchased really cheaply on-line.