When to change brake fluid?

reeac

I own a 1958 MGA which I restored and put back on the road in 1983. After about 15 years I started getting problems with brake wheel cylinders seizing and had quite a few years of such problems until one day someone asked me how often I changed the brake fluid. I then realised that I'd never changed it since the restoration. I ended up getting a garage to change all the hydraulics and everything's been fine since then ....due for a fluid change about now. I get the fluid changed on my other cars (which I've owned for 12 and 16 years) every 4 years. In short I think that you can get away without fluid changes for maybe 5 or 6 years but any more is false economy.

Nodding_Donkey

fred246 wrote: »

I have read the trade literature. Scare your customers - juicy profits.

LMAO

Juicy profits in a £30 brake fluid change?

thescouselander

Iceweasel wrote: »

Can you guarantee that?

Ever been to Switzerland or Austria on holiday?

Have you seen what real hills are like?

How many years do you think brake fluid lasts?

I bet you would say that you've never had a problem with not changing brake fluid.

Think about it.

Everyone doesn't potter about at low speed.

Giving advice not to change brake fluid could lead to a nasty accident.

I reckon fred has a point. It would be quite feasible to change the brake fluid "on condition" rather than to a fixed schedule since brake fluid is easily checked. Many garages will charge £50 to change the brake fluid - it's a quick job and the materials cost hardly anything so it's a nice little earner as far as the garage is concerned.

daveyjp

Chances are brake fluid is now more general hydraulic fluid and used for more than just brakes.

£30 every couple of years to prevent more expensive problems doesn’t sound excessive to me.

AdrianC

fred246 wrote: »

I doubt many garages would truly flush out all your brake pipes.

It's a lot easier if you just admit you don't know how brake fluid is changed, y'know.

daveyjp wrote: »

Chances are brake fluid is now more general hydraulic fluid and used for more than just brakes.

Such as...?

The only other hydraulics on a car used to be the power steering - which used a different fluid, and were on a separate circuit. But that's now almost universally electric.

marty2be2000

AdrianC wrote: »

Such as...?

The hydraulic clutch in my Volvo, shares the same fluid. Symptoms of slave cylinder issues include brake fluid loss.

On my Audi the recommended change interval on the brake fluid is every 2 years regardless of mileage. It's due again in 2018 and will be changed, I'd rather have piece of mind that the pedal and brakes are connected correctly given my Audi weighs almost 2 tons.

daveyjp

AdrianC wrote: »

It's a lot easier if you just admit you don't know how brake fluid is changed, y'know.


Such as...?

The only other hydraulics on a car used to be the power steering - which used a different fluid, and were on a separate circuit. But that's now almost universally electric.

Clutches.

From my handbook:

“The reservoir is used for both brake and clutch systems and has chambers for both systems”

AdrianC

OK, yes - clutches. Sometimes shared reservoir, sometimes not. I wouldn't call that "general hydraulic", though... But that's because I tend to think of hydraulics being wider in terms of Citroens (which decoupled the brakes from the hydraulics to a normal DOT system back in 2001 with the C5)

Richard53

fred246 wrote: »

If it isn't changed you won't have any problems.

Tripe. Replace won't with may not, and we might agree.

• On a long descent, brake temperatures can get up to 400C and above.
• Water boils at 100C.
• If there is any water in your brake fluid (which, by its nature, absorbs water over time), it will turn into steam in that situation.
• Water is not compressible, but steam is.
• Pedal goes to floor, no brakes.

It's happened to me, and it isn't much fun. I now change my brake fluid every 3-4 years. 2 years is probably excessive, but ignoring it is foolish, and advising others to ignore it is potentially harmful.

AdrianC

<nods>
<quick google>
Dry boiling temperature of new DOT4 fluid is 230degC. Wet boiling temp can come down as low as 155degC.

I've had old, wet fluid boil on me. It's not much fun, especially when you consider the circumstances where it's most likely to boil - descending a Portuguese mountain in 30degC+, in this case.

And that's before we consider the corrosion risk.