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Brake Fluid

Community Veteran
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Registered: 02-08-2007

Brake Fluid

According to the service manual  brake fluid should be changed after x thousands of miles, the actual number varies with the make of car.

This is recommended due to the fluid attracting air and becoming less efficient.

Although I have changed brake fluid on several cars I have had in the past it was only because I was doing some other work connected to the brakes and it made sense to complete that job as well, usually taking no more than 5 minutes to complete unless the bleed screw is rusted up in which case......a lot longer.

Question is have you ever changed the Brake fluid at the recommended interval ? Is it necessary to change it ?

Sure you should check the level or investigate any leaks or spongy feeling when applying the brakes but have you ever actually changed it in line with the service manual ?

16 REPLIES
Community Veteran
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Registered: 30-07-2007

Re: Brake Fluid

Brake fluid is hygroscopic. I believe the recommendation is to replace it every 2 years. It doesn't really depend on mileage.

However, garages can check the water content to see if it really needs changing, problem is it's easier (and more lucrative) for them to just say it's needs changing. Both my company car and my wifes car go to the same local garage for servicing and when hers went for it's 2 year service, rather than just replace (since she only does about 1000miles/year ), they were willing to test the fluid for water content. On my company car, they just replace it at 2 years....

 

nanotm
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Re: Brake Fluid

in the past I used to put my car in the garage for the biannual service and fluids change, I'd have the water, brakes, breakfluid, wipers, oil, and filters changed every time, it was at that point a standard service offered for about £150, and since I was doing on average a thousand miles a week it made sense to me to be proactive and not rely on chance..... of course that was many years ago and I understand prices have moved on since I lost my licence/

 

 

 

just because your paranoid doesn't mean they aren't out to get you
Community Veteran
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Registered: 01-08-2007

Re: Brake Fluid

Got to be honest we've rarely had ours done at all. Actually it's only been done once on the reanult thats been sorn since 2010 and thats because the steel brake pipes had rusted through and then disintegrated when i removed the rear subframe.

Personally i think steel brake lines are a stupid idea and should also be a service item. I had to strip out the entire lot for the rear and re-do them as some of you may remember me seeking advice about. It was a bit of a faff but got there eventually.

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PowerLee
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Re: Brake Fluid

As already mentioned, brake fluid is hygroscopic.

 

As well as the risk of the absorbed water boiling during sustained heavy braking there is also the potential problem of braking system internal metal components suffering from corrosion damage.

 

ABS / ESP hydraulic modulators are expensive to replace precision hydraulic components, brake fluid saturated with water inside the hydraulic modulator could cause all sorts of expensive damage.

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Re: Brake Fluid

When my Focus was serviced in 2014 by a main agent I was advised...Brake Fluid Level OK - Water Content 3% which was above the manufacturer's recommended level.

They advised a drain, flush and replacement which I agreed too...£35

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RichardB
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Re: Brake Fluid


PowerLee wrote:

As already mentioned, brake fluid is hygroscopic.

ESP hydraulic modulators are expensive to replace precision hydraulic components, brake fluid saturated with water inside the hydraulic modulator could cause all sorts of expensive damage.


 

I completely  agree.

Whilst drum brake cylinders are cheap and disc brake calipers are moderately expensive to replace, ABS modules are eyewateringly expensive to replace.

Not changing the brake fluid for £30 to £40 every few years is a false economy.

Minivanman
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Re: Brake Fluid

Never aware of this and have only ever just topped up. Has it ever been and issue and something to attend to? Well it will be now Thumbs Up

All views expressed are my own but you can express them too if you want to be right about everything like I am.
Pete11
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Re: Brake Fluid

I have mine changed every year regardless of the mileage. Condensation, hard braking (at times), build up of little air bubbles etc. all can cause a problem. So every year it's down to the garage and the brake fluid gets changed along with the service.

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bjallenby
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Re: Brake Fluid

There's a subreddit where mechanics post pictures of vehicles that have come into their shop for work. One guy had a vehicle come in for a head gasket. The customer was religious in changing ALL fluids in the vehicle every 5k miles. They cracked the head off the engine and it was as clean inside (if not better) than it was the day it left the factory. It was a "holy [-Censored-]" moment when I saw the pictures. I wish I could find the damn thread.

Not the car I'm talking about, but here is a Ford Courier (89-91) with 500,000 km. https://i.imgur.com/WLGqxV2.jpg

Maintenance will get your car to the moon and back.

nanotm
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Re: Brake Fluid

@bjallenby

 

indeed we had a truck when I was in the mob that had been serviced every month and given a major overhaul every year that dated back to the 50's with its original engine still fitted back in the late 90's, that thing had been round the clock on the odometer half a dozen times and the only way to get rid of it was donation to a military museum,  I doubt its been used since it left our depot but there was nothing wrong with it when it did, then again vehicles aren't built to last anymore and no amount of care will keep a modern vehicle on the road much over a decade without serious overhauls not to mention a full reskin /

just because your paranoid doesn't mean they aren't out to get you
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Re: Brake Fluid

Th primary reason for the built-to-break mentality these days is because of the people who kept something going seemingly forever, the manufacturers saw this as a money-loss system, so, they design in ways to make things fail prematurely, therefore making the end-user either stump up for expensive repairs and parts, or, buy a whole new one instead, this way the manufacturers keep profiting on failures they have created...

Community Veteran
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Re: Brake Fluid

Do you need to change the fluid if you have air brakes?

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bjallenby
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Re: Brake Fluid


twocvbloke wrote:

 this way the manufacturers keep profiting on failures they have created...


https://en.wikipedia.org/wiki/Planned_obsolescence

nanotm
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Re: Brake Fluid


twocvbloke wrote:

Th primary reason for the built-to-break mentality these days is because of the people who kept something going seemingly forever, the manufacturers saw this as a money-loss system, so, they design in ways to make things fail prematurely, therefore making the end-user either stump up for expensive repairs and parts, or, buy a whole new one instead, this way the manufacturers keep profiting on failures they have created...


and when this proved to be a failure they had the EU pass legislation that forces regular replacement, oh they still put in the planned failures but there less likely to actually fail as required and cause them more problems with early failures they have to fix themselves, so now they build out of things like fibreglass that delaminate over time no matter how well you look after it, and once that starts its a wreck job, but of course there's always the regular expensive things that go wrong like the catalytic converter (or more often than not the cheap sensor that you cant replace on its own...) 

never mind that there trying to get rid of the second hand car market it wont be long now before folks have to buy their recyclable vehicle from the factory every 5 years only for the old one to end up rotting in a pit instead of being recycled ...

 

 

just because your paranoid doesn't mean they aren't out to get you