Opinions on cam belt replacement and brake fluid

Stubod

..must admit our last car was 17 years old when we sold it and don't recall ever having the fluid changed!? Accept 17 years is probably taking it to the extreme but we never had a problem with the brakes / MOT. (I think most recommend 2 yearly which I think is a bit OTT?). I think at 5 years it's probably a good idea to get it done.

Our last car also had manufacturers recommended timing belt change at 60k miles but they did not put any time limit on it. As we did not do many miles it got it done at about 10 years with 30k on the clock.  

AdrianC

Stubod said:

..must admit our last car was 17 years old when we sold it and don't recall ever having the fluid changed!?

Did you ever have any brake calipers or wheel cylinders or flexi hoses or rusty pipes changed on it...?

photome

Thanks for comments guys. Will et the cambelt done. most likely the brake fluid as well , but I dont normally agree with Fred but how does water get in a sealed system, and in days gone by 70s and 80s and 90s I dont recall changing fluid on cars that I had for a few years and back then I used to do most things myself
ps Seat give a 5 year warranty on the cambelt if they do it

frost500

Water gets every where, it is the ultimate solvent. The brake system is not totally sealed to aerospace standards, if it was cars would cost 10x more. Hence a recommended change interval of 2 years. The moisture gets in a joins, calipers, caps etc. Brake fluid is hard, you can't compress it. Moisture can be compressed, that's why it bubbles. Hope this makes sense. Neglecting a brake fluid change can kill somebody, and it won't be the driver, it will be a kid crossing the road. GET IT DONE Please, regardless of the experience of chancers.

fred246

The manufacturers basically like to say that their experience of motorsport helps them to improve their cars. So things learned on the track can be applied to passenger cars. So race drivers drive with their brakes at 300 degrees so Joe Public does too. Theoretically Joe Public could if he was daft enough. And some drivers ARE daft enough. I am not one of those.

AdrianC

photome said:

most likely the brake fluid as well , but I dont normally agree with Fred but how does water get in a sealed system

It isn't sealed. If it was sealed, the fluid level in the reservoir couldn't drop as the friction material wears.

and in days gone by 70s and 80s and 90s I dont recall changing fluid on cars that I had for a few years and back then I used to do most things myself

The fluid has changed since then - for the better...
Back then, you'd have been using DOT3, which has a much lower boiling point, so boils much more readily once wet.
Drum brakes don't get as hot as discs, though, simply because there's more thermal mass - and also because cars weren't as heavy back then.

If you did much beyond basic oil-changing-only, then I would bet that you replaced brake pipes or cylinders... Why? Because the cylinders were leaking because they were pitted and rusty internally...?

AdrianC

frost500 said:

Brake fluid is hard, you can compress it. Water can be compressed, that's why it bubbles. Hope this makes sense.

Nope, it doesn't.

Basic physics - liquids are not compressible. Gases are.
Water boils at 100deg. "Dry" DOT4 brake fluid boils at 230degC.
The more water in the brake fluid, the lower the boiling point. Steam is compressible.

THAT's why when you "cook" your brakes, the pedal needs pumping up - because you're compressing the steam, just the same as you're compressing air when the brakes need bleeding. When the fluid cools again, that steam condenses and is absorbed back into the fluid.

HansOndabush

I have never changed brake fluid for the sake of it in decades of motoring and having some very old cars. Never had a problem. The newer synthetic fluids are better than when I started driving too. I don't think there is any reason to change brake fluid though if you are changing pads, then its a good idea to bleed the fluid out of the caliper nipple while you compress the piston; that will change the fluid in the caliper.

HansOndabush

Homer_home said:

If your brake fluid is old and has water in , when the brake fluid gets hot it will bind your brakes and eventually they will lock on , until they cool down then they will release 

You can tell when your fluid needs changing as on a hot day your brakes will be a lot sharper and require less pedal travel to brake 

Complete nonsense; not even worth a proper reply.

fred246

There is no definition of what brake fluid change really means. I have seen people say. "Remove brake fluid from reservoir with syringe. Pour in clean fluid". It's a sort of brake fluid change. I can't imagine a garage spending hours making sure every molecule is changed. No-one will have a clue if they have done anything anyway. Just big money making exercise for garage.