But the calipers won't be new and zinc plated any more. Neither will the ends of the pistons where they bear against the back of the pad. Plus, for those that use those horrible stainless guides pressed into the iron caliper, for the pad ears, there is likely to be corrosion under then, making them a tighter fit. I agree that some folk really slather the stuff on excessively, but a tiny smear can, I think, be beneficial.
Changing pads - advice
- Thread starter dishman
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But the calipers won't be new and zinc plated any more. Neither will the ends of the pistons where they bear against the back of the pad. Plus, for those that use those horrible stainless guides pressed into the iron caliper, for the pad ears, there is likely to be corrosion under then, making them a tighter fit. I agree that some folk really slather the stuff on excessively, but a tiny smear can, I think, be beneficial.
You're talking about older hoses. Modern ones have had a waterproof lining for quite a few years now.
No, I think even today's are permeable. When do you think this change took place?
It started in the 80's when flexible brake lines started to be made from fibre reinforced EPDM but i couldn't tell you exactly when they became standard fit.
Its a bit like car exhausts. I couldn't tell you exactly when the started making them from a higher grade of steel that didn't corrode in the same way, but when did you last change an exhaust for corrosion on a modern car?
I've always thought that a yearly change of brake fluid - to minimise the effects of water absorbsion - was a bit of a garage con.
John
John
Yearly is way too much. Bi-annually is probably still too much, but manufacturers will always err on the safe side when there is money to be madeI've always thought that a yearly change of brake fluid - to minimise the effects of water absorbsion - was a bit of a garage con.
John
My father in law just had to spend quite a bit of money on the brakes of his 1978 Rolls Royce silver shadow. He'd last changed the brake fluid in 1997. However, apart from failed high pressure pumps the rest of the system just needed a good flush and will hopefully be good for another 25 years
The biggest issue with water absorption is that it lowers the boiling point of the brake fluid, and brake fluid that has absorbed water becomes denser and makes it's way to the lowest points of the system which is typically the callipers. The callipers are the points of the hydraulic braking system where the most heat is generated, so boiling brake fluid is more of an issue than corrosion in modern brakes.
I understand your comment on water lowering the boiling point of brake fluid of course - but that now should be minimal if flexy hoses are now impervious to water absorbtion.
Dead right about car exhausts of course! Maybe that's due to the materials being coated or helped by unleaded fuels - I really don't know.
Pity they don't do the same with the clamps and hangers though!
John
Dead right about car exhausts of course! Maybe that's due to the materials being coated or helped by unleaded fuels - I really don't know.
Pity they don't do the same with the clamps and hangers though!
John
Exhaust longevity is as much to do with lower suplphur fuel as anything else. It creates less sulphuric acid.
I've always thought that a yearly change of brake fluid - to minimise the effects of water absorbsion - was a bit of a garage con.
John
It's every 2 years in my EV. (And the manufacturer is desperate to find something to service - a pollen filter is the only other thing he can sell me)!
Yearly is way too much. Bi-annually is probably still too much, but manufacturers will always err on the safe side when there is money to be made
My father in law just had to spend quite a bit of money on the brakes of his 1978 Rolls Royce silver shadow. He'd last changed the brake fluid in 1997. However, apart from failed high pressure pumps the rest of the system just needed a good flush and will hopefully be good for another 25 years
The biggest issue with water absorption is that it lowers the boiling point of the brake fluid, and brake fluid that has absorbed water becomes denser and makes it's way to the lowest points of the system which is typically the callipers. The callipers are the points of the hydraulic braking system where the most heat is generated, so boiling brake fluid is more of an issue than corrosion in modern brakes.
Doesn't the Shadow use the Citroen system with mineral oil in it?
I think the first EPDM-lined brake hoses were tried in the 1950s? Certainly they were common by the 1960s. Without doubt they absorb less water than rubber, but they do still absorb water!
Same on my hybrid but I have a pre-paid 4 year service plan so no skin off my schnozz.It's every 2 years in my EV. (And the manufacturer is desperate to find something to service - a pollen filter is the only other thing he can sell me)!
My car has had 2 year brake fluid changes with the main dealer.
But when I recently moved to an independent mechanic and told him it was due, he scoffed at it. Told me it can go much longer and was just over cautious manufacturers and main dealers making ££.
One thing i have noticed however where the reverse seems to be true, is that a lot of manufactures claim 10 year coolant life on their latest formulations.
However if you buy that formula/spec in shops, they only ever quote 5 years. Seems the parts suppliers are more cautious on that front.
But when I recently moved to an independent mechanic and told him it was due, he scoffed at it. Told me it can go much longer and was just over cautious manufacturers and main dealers making ££.
One thing i have noticed however where the reverse seems to be true, is that a lot of manufactures claim 10 year coolant life on their latest formulations.
However if you buy that formula/spec in shops, they only ever quote 5 years. Seems the parts suppliers are more cautious on that front.
