It's probably a WW11 variant when bananas were unknown but Spam was an everyday food. The meaning of being naive is agreed on.

Most of my family were in the mercantile navy out of Leith, not the Clyde.

Preventative maintenance sounds better to me than being diddled out of £50.

Brake failures are not easy to forget.

 

37 minutes ago, Scot5 said:

 

Yep heard it all b4.

 

As I replied earlier that 'spongy' feeling doesn't exist according to certain garages - one minute you're brakes are 100% effective, next you're going to plough in to a brick wall apparently. I'd sugest these are garages who either dont know how brakes work or are simply frightening you in to parting with money. Or both.

 

The three years thing I get but you you haven't explained why after 30 odd years, they've changed from two years to three?  (Before 30 odd years, I can't recall anyone mentioning ever mentioning brake fluid change - all of a sudden this two year rule was introduced. If I remember rightly, the two year rule co-incided with longer service intervals (used to be every 5k or 6k). Being a sceptic, I'd suggest it had more to do with generating revenue to compensate for the longer service intervals but have no proof whatsoever.

 

I know people change it every two years, there's nothing wrong with that whatsoever, but I've yet to hear anyone who's brakes have failed due to water ingrees. The point is does it need changing? Have you ever checked the water content in the brake fluid you've thrown away after 2yr?  Who's to say the fluid in your car isn't as good as the day it was installed.

 

As per above, will be very interesting to see how many 3yr old cars (other manufacturers say every 2yr from new) or 4 or 5 or 6 year old cars fail their MOT because of water ingress. As far as I'm aware it's the first time anyones studied it because thus far it's all theory and gut feeling.

 

Oil isn't tested before being changed - do you apply the same logic to that?

 

Another point - anyone who tows frequently will be asking more of their brakes, and the risk of overheating is higher.

 

FWIW, I value the lives of my family and I higher than the £50 or so to change brake fluid every couple of years...

 

Also, I doubt many cars that have had brake failure have the fluid tested after the event, so 'proving' that it was water ingress may be somewhat challenging. Especially if the car ended up under a truck or in flames 

Edited 6 August, 20187 yr by pist0nbr0ke

If you have ever had no brakes, other than the handbrake, coming down Hardknott Pass due to water boiling in the brake fluid you would not query changing standard brake fluid every 2 years. There was no indication of any problem prior and when I stopped and let everything cool down the brakes were fine again. The brake fluid was changed the following day. I really do not like having to change my underpants after a drive. 

1 hour ago, CWARD said:

 

Not changing brake fluid allows it to absorb more moisture over time. The more it absorbs the softer the pedal becomes decreasing braking performance which is more noticeable than lowering the boiling point of the fluid as most drivers won’t get their  brakes that hot anyway. 

 

I don't think brakes go spongy due to water (when in liquid form) as water is not compressible. It will only go spongy if there is air in the system or water vapour forms when water content boils. 

 

Another potential problem not mentioned is that water freezes at a relatively mild 0C. High water content in winter could, I suppose, cause havoc with the braking system especially the high tech ABS etc when ice crystals form.

Edited 6 August, 20187 yr by xman

You asked for an example of brake fluid causing brake failure. My brother had a Mitsubishi Shogun Sport and couldn’t remove the calipers to change the rear discs. After much persuasion we were able to retract the pistons enough, but not enough to go over the new discs, nor would they pump out much either. I had him bring it to mine were I could work on it better and ordered new brake pistons and seals as we could see rust on the outside off the piston. Removing the calipers to refurb them I tried to blow the piston out using compressed air which has never failed but this time it did. I ended up using a vice, clamps and air to wrestle the pistons out. When the pistons were finally removed they had rust on both sides of the seal with only a small area clean of rust from were the seal was. There had been no fluid leakage through the seal so the rust on the piston that had been behind it must have been caused by the moisture in the fluid as it is a sealed system. The piston rust had prevented the rear brakes from working. 

Changing the brake fluid after renewing the pistons and seals showed it was very dirty but at the reservoir it looked fairly clean. 

 

Changing brake fluid isn’t going to make a dealership rich when they can fleece you in other much more profitable ways. If that’s all you can do to argue against having the brake fluid changed then take your business to an independent or learn how to do it yourself. 

23 minutes ago, xman said:

 

I don't think brakes go spongy due to water (when in liquid form) as water is not compressible. It will only go spongy if there is air in the system or water vapour forms when water content boils. 

 

Exactly that reason

 

Ice forming in the brake system shouldn’t be an issue as the brake fluid will lower the freezing point but also lower the point of the water content too. 

I know with air braking systems, ice can be an issue and alcohol is a see to dry the air and air tanks are drained when not in use to prevent ice formation. 

One thing that is astonishing with brake fluid is the amount of gas contained within it. If you have ever replaced Dot 5.1 on a mountain bike, one procedure describes degassing the fluid to prevent sponginess by drawing up a syringe, sealing it off and drawing back further on the plunger whilst tapping it to get the bubbles to the top, about 5% gas comes out!!!

8 hours ago, Scot5 said:

 

I don't doubt that for a second and it's good advice. But the question is, does Miso soup stop the car?  As per my answer above - my issue is that people are changing things without testing.

 

After two years from new, a garage recommended a brake fluid change. I refused on the basis I was happy with my brakes. I said that if I detected they weren't working effectively I'd have them looked at / fluid changed. The reply I got was startling. They told me I wouldn't experience any degregation - my brakes would work 100% one second but experience total failure the next due to water content.  So I asked them to test the current water content of my brakes.  " Oh we don't do that sir, we just replace the fluid as routine ".

 

 

 I know of one death because of internal brake system rusting and it's one too many.

 

Testing the master cylinder for water content isn't enough as it only tells you about the latest fluid put into the system and not what is further downstream.

 

The safest dual circuit system I've encountered was on a Volvo where each front caliper was fed by both circuits and had two pistons and bleed nipples each. Good job as that is what the Miso soup came from! This pre-dated ABS but the dual circuit failure detector was in a bad way with internal rust and had to be replaced - that was a job an a half as I ended up replacing lots of brake pipes to do this. I thought the master cylinder resevoir was black - until the system was filled with clean brake fluid and it became a light straw colour. 

 

For me - every two years without fail.

 

 

 

 

Dear all

Thank you for your very thought provoking comments.  I will definitely have mine changed at the first three year mark.

 

Thanks

Stewart

I too, agree regular changes are a necessity. That said, you are more likely to throw away decent fluid then contaminated fluid if you change every vehicle, every two years. There will always be someone who has contamination and is driving on the edge, whilst others are swapping perfectly acceptable fluid for fresher but not really better fluid just to be sure and THAT is the big point... Being sure! Don't change it, you risk being one of the unlucky ones and who wants their brakes to fail, whilst travelling at speed, their car full of loved ones?

 

I do believe dealers/garages are aware of the scare tactics and may even go some way to over emphasise this, to make bookings but it will most likely be worth doing the change at least now and then. One person here stated they never change theirs but then suggested if they purchased a used car, they would do it without hesitation. This could be a total red herring. Why would you assume the last owner never did the job? It may have been done prior to sale as a way of ensuring the brakes felt powerful and stopped the car nicely and without fuss. A great selling point! If you don't trust the sellers maintenance, why buy the old shocker he/she is selling? 

 

All this and more, is just opinion and POV.

If you think you are being ripped off and the brakes feel great, change it every three years instead. If you think the car needs an anchor thrown out the back window every time you need to come to a halt, get it done now and then every two years, regardless or get shot of the pile of carp!

 

Its the same argument here as changing the a/c gas but not changing the gas makes the journey unpleasant if it fails, whereby failed brakes and you will feel nice and comfy in that satin lined, pine box.