Brake Fluid Test in Health Check

hi with a electronic tester. brake fluid absorbs water so i would get it changed as you may fine the brakes fluid boils under heavy braking

doh you may find the brake fluid boils under braking mileage is not important age is

Is the probabilty of total brake failure due to the fluid boiling unimportant to you then?

Try going down Porlock Hill in Somerset with a fully laden car on a hot day with water in the brake fluid - and you will see and feel the importance of changing the brake it every two years.

Yes, after having experienced total brake failure on Porlock, with my wife and kids in the car some 30 years ago, I have the fluid changed at every other service since regardless of the cost or what the fluid test and mechanic says.

It's worth sticking to the maker's schedule for such things if you intend keeping the car. Apart from any safety issue, callipers etc have a longer service life if the fluid is changed regularly.

Do you know how old the fluid in use was then?

At one time, it was never changed at a routine service.

Only if the gorillas at the garage don't pump it out with the brake pedal. I'm sure the master cylinder failure on my last car was directly caused by a brake fluid change.

Tim

If the master cylinder has corrosion, then yes, using the pedal full stroke can and does finish off the master cylinder, I have seen it several times. However, it meant two things: one : the fluid had not been changed often enough, and two: the cylinder needed replacement anyway, even though it worked fine for normal use before the fluid change. Nowadays, most garages would be likely to use a powered version of the gunson easy bleed, so the pedal does not get pumped.

Vehicle was only 5 or 6 years old and fluids changed regularly by main dealer. All I know is that before the last fluid change, the brakes were fine. Afterwards, the pedal started sinking to the floor under sustained pressure.

Maybe the master cylinder was already corroded but it had been maintained as per manufacturer's recommendations.

Tim

Maybe, but often such items as fluid change are not actually done, even if they are charged for.

Quite. I had an oil change not done at a BMW main dealer once. And it was mainly just an oil service. ;-)

I also had the brakes fade on Porlock Hill. Not an experience I would like to repeat.

Thanks for all the informed opinion, and for pointing out the severity of Porlock Hill. I negotiated Porlock in the sidecar of a Sumbeam S7 in 1957. It's not on my bucket list. ;-)

The consensus seems to be that it ought to be done every two years, even though there is no suggestion of spongyness in the pedal, which is when it was normally deemed necessary in the Good Old Days, if (bleeding didn't cure it).

I have the car on a service contract, paid monthly, so I also see it as a little extra income for the dealer, in the same way that retail outlets try to sell us insurance cover on TVs and white goods.

In the old days the fluid was a different spec.(dot3) Modern fluid (dot4) has a better spec when fresh, but degrades with regard to boiling point more rapidly than the old stuff did, and therefore needs changing more regularly. The 30 odd quid for fluid change every two years is pretty good insurance against failure or problems with brake components at a later date.

I see.

The 30 odd quid for fluid change every two years is

Point taken.

replace brake fluid every year for the sake of £30 pounds its just not worth the hassle, bend your car because of brake failure and its down to lack of maintenance some insurance companies will not pay out My new van , oil change every 2 years fuel , air and oil every 4 not a chance new filters all round fresh oil every 12 months or 30 K

I Change my fluids myself , i just don't trust dealerships. refurbing one in brum, fasted service you ever did see in the front of the workshop out the back free valet parked up for collection, might get oil topped up if lucky wiped filters down with a rag.

Very sadly, it's probably the case more often than most realise.

In my case, I dipped the oil after looking to see if a leak had been fixed. Which I'd been charged for. It hadn't. Nor had they even cleaned up the parts.

The oil level was just above minimum. In the level garage car park. Difficult to tell if it was new oil or not - it never got dirty anyway. The oil filter housing on the top of the engine looked like it hadn't been touched.

Service manager said it was impossible. Their equipment dispensed the correct amount of oil for each model, so it had to be right. And said I obviously didn't know how to check the level. Talk about a red rag to a bull. ;-)

I had a clutch master fail while changing the fluid once.

Stripping it down showed that the inside of the bore was absolutely f***ed - corroded to the point that the return spring inside was a nasty little lump which just collapsed when I poked it.

The most likely scenario is that your dealer told you they'd changed the fluid, but hadn't.

Sounds about right, its an easy £45.00 a bit like the engine flush not needed on modern cars with modern oils.