what about the corrosion in master cylinders? where does it come from? it's always on the "wet" side, not the sealed/dust boot side.
i prefer to replace brake fluid at every brake job.
i prefer to replace brake fluid at every brake job.
brake fluid really need to be changed?
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Yeah, I have nothing except facts and logic on my side. I do notice that most of you that fail to recognize the importance of rebuilding the calipers come from warmer climates. We all know that heat is rubber's worst enemy. On the other hand, we know cold can hurt rubber's sealing ability, ''Houston, we have a major malfunction''. I am wondering if ice and snow packed into the wheel well can drive salt, moisture, and grit past a cold stiffened boot. Once there, as the piston continues its mostly outward movement, it corrodes the piston.
The brake shop I worked in insisted on rebuilding all the wheel cylinders and calipers with any relining job. We did mostly trucks, but not all of them had hydraulic brakes. Of course we sold a lot of stuff over the counter and rebuilt parts carried in. That was where I saw most of the real horrors. Often a day or 2 after selling a set of pads, the guy would be back with a caliper or 2, either stuck or leaking. In many cases the guy would have done better to buy a rebuilt one at Auto Zone. Labor, a kit, and a piston added up to more. Broken bleed screws were common too. When I made up new brake lines, the old ones that leaked, were always heavily pitted on the outside. Never remember checking the insides.
I just can't buy flushing the brake fluid doing a caliper much good. The fluid no longer touches the piston outside the seal. It comes in at the bottom, and goes out at the top. I wonder if it can carry the flakes of rust and other stuff up and out. Does it flush out the narrow annular space between the piston and the caliper bore? It may reduce pitting of the caliper bore, but that isn't a big problem. I never remember discarding an iron caliper casting. Sometimes we gave up an an aluminum one because we couldn't heat it enough to free the bleed screw without melting it.
I do have to admit my experience has not included Bosch ABS. I notice it is mostly manufacturers using it that are recommending changing brake fluid. Perhaps its design is overly sensitive to contamination.
As for changing my brake fluid when I change the other fluids, my owners' manual doesn't recommend changing anything except the oil before 150K or 5 years for the coolant. It is interesting the Germans have so much confidence in the factory fills for the Getrag transmission, and so little for the Bosch ABS.
The brake shop I worked in insisted on rebuilding all the wheel cylinders and calipers with any relining job. We did mostly trucks, but not all of them had hydraulic brakes. Of course we sold a lot of stuff over the counter and rebuilt parts carried in. That was where I saw most of the real horrors. Often a day or 2 after selling a set of pads, the guy would be back with a caliper or 2, either stuck or leaking. In many cases the guy would have done better to buy a rebuilt one at Auto Zone. Labor, a kit, and a piston added up to more. Broken bleed screws were common too. When I made up new brake lines, the old ones that leaked, were always heavily pitted on the outside. Never remember checking the insides.
I just can't buy flushing the brake fluid doing a caliper much good. The fluid no longer touches the piston outside the seal. It comes in at the bottom, and goes out at the top. I wonder if it can carry the flakes of rust and other stuff up and out. Does it flush out the narrow annular space between the piston and the caliper bore? It may reduce pitting of the caliper bore, but that isn't a big problem. I never remember discarding an iron caliper casting. Sometimes we gave up an an aluminum one because we couldn't heat it enough to free the bleed screw without melting it.
I do have to admit my experience has not included Bosch ABS. I notice it is mostly manufacturers using it that are recommending changing brake fluid. Perhaps its design is overly sensitive to contamination.
As for changing my brake fluid when I change the other fluids, my owners' manual doesn't recommend changing anything except the oil before 150K or 5 years for the coolant. It is interesting the Germans have so much confidence in the factory fills for the Getrag transmission, and so little for the Bosch ABS.
Is it the Germans saying that or GM?
GM recommends has a lifetime factory fill on my ZF Corvette tranmission, ZF recommends changing the fluid.
Kestas
Staff member
In the number of brake fluid threads we've had this past year, it appears that all members but one agree on the value of regular brake fluid flushes.
The changing your brake fluid issue is the same as the changing your differential fluid issue. Yes there are stories of people going 10 years or 200,000 miles without ever changing the fluid and have no problems.
So let’s just look at this whole thing like a business would maintain a fleet. Cost vs. risk. You do maintenance to reduce the risk of component failure and down time and ultimately subsequent cost. Your maintenance costs have to be less than the repair down time costs. Otherwise it’s more cost effective to leave it alone until it requires fixing.
Not changing any fluid system just increases the risk of corrosion over time and accelerating the subsequent down time.
Brake fluid, as many other system fluids, has an additive package to neutralize the effects of contaminants that induce corrosion. These additives are neutralized during the process and eventually get depleted. Several recent studies indicate that for DOT 3 brake fluid the package is 90% depleted in roughly 3 years.
So, just as engine oil, transmission fluid, differential fluid and power steering fluid have sacrificial additives that have to be replaced and the depletion rate for these different systems vary you have to change them before they are depleted and accelerated corrosion begins.
So! If you think about it and you take a rather selfish hard core business attitude. If you are only going to keep a vehicle for 4-5 years why bother to change fluids such as brake, differential, power steering. However, if you plan to keep your vehicle for a decade plus you would change the fluids to reduce your risk of component failure and higher costs.
Then again if you are a sentimentalist… If you love your baby (vehicle) you’ll take care of it because you love your baby
.
So let’s just look at this whole thing like a business would maintain a fleet. Cost vs. risk. You do maintenance to reduce the risk of component failure and down time and ultimately subsequent cost. Your maintenance costs have to be less than the repair down time costs. Otherwise it’s more cost effective to leave it alone until it requires fixing.
Not changing any fluid system just increases the risk of corrosion over time and accelerating the subsequent down time.
Brake fluid, as many other system fluids, has an additive package to neutralize the effects of contaminants that induce corrosion. These additives are neutralized during the process and eventually get depleted. Several recent studies indicate that for DOT 3 brake fluid the package is 90% depleted in roughly 3 years.
So, just as engine oil, transmission fluid, differential fluid and power steering fluid have sacrificial additives that have to be replaced and the depletion rate for these different systems vary you have to change them before they are depleted and accelerated corrosion begins.
So! If you think about it and you take a rather selfish hard core business attitude. If you are only going to keep a vehicle for 4-5 years why bother to change fluids such as brake, differential, power steering. However, if you plan to keep your vehicle for a decade plus you would change the fluids to reduce your risk of component failure and higher costs.
Then again if you are a sentimentalist… If you love your baby (vehicle) you’ll take care of it because you love your baby
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Dad's truck is still on factory diff fluid with 217k and 14yrs.quote:
Originally posted by johnnyo4:
The changing your brake fluid issue is the same as the changing your differential fluid issue. Yes there are stories of people going 10 years or 200,000 miles without ever changing the fluid and have no problems.
So let’s just look at this whole thing like a business would maintain a fleet. Cost vs. risk. You do maintenance to reduce the risk of component failure and down time and ultimately subsequent cost. Your maintenance costs have to be less than the repair down time costs. Otherwise it’s more cost effective to leave it alone until it requires fixing.
Not changing any fluid system just increases the risk of corrosion over time and accelerating the subsequent down time.
Brake fluid, as many other system fluids, has an additive package to neutralize the effects of contaminants that induce corrosion. These additives are neutralized during the process and eventually get depleted. Several recent studies indicate that for DOT 3 brake fluid the package is 90% depleted in roughly 3 years.
So, just as engine oil, transmission fluid, differential fluid and power steering fluid have sacrificial additives that have to be replaced and the depletion rate for these different systems vary you have to change them before they are depleted and accelerated corrosion begins.
So! If you think about it and you take a rather selfish hard core business attitude. If you are only going to keep a vehicle for 4-5 years why bother to change fluids such as brake, differential, power steering. However, if you plan to keep your vehicle for a decade plus you would change the fluids to reduce your risk of component failure and higher costs.
Then again if you are a sentimentalist… If you love your baby (vehicle) you’ll take care of it because you love your baby.
For some reason I thought most bikes used DOT5.
I have seen many calipers on late '60s early '70s Saabs that corroded on the fluid side of the piston seal due to moisture in the fluid. I even had to throw some away because the corrosion was so bad the chrome-plated pistons were pitted.
I might even be able to find a couple in storage for pictures if I had to (maybe if I get around to stripping the '72 in my dad's back yard)
Kestas
Staff member
Not most bikes, but Harley-Davidson specifies DOT 5 (silicone-based) for their factory fill brake fluid. They are the only vehicle manufacturer that specifies DOT 5.
Kestas,
I've wondered for yrs why HD uses DOT 5. I can only guess it's:
1. The brakes have a better chance of working after 10 yrs of neglect. (I know plenty of bikers who just WON'T bleed brakes).
2. Spilled fluid won't harm the paint.
Any guesses?
I've wondered for yrs why HD uses DOT 5. I can only guess it's:
1. The brakes have a better chance of working after 10 yrs of neglect. (I know plenty of bikers who just WON'T bleed brakes).
2. Spilled fluid won't harm the paint.
Any guesses?
Kestas
Staff member
We had a VP from Harley-Davidson speak at one of our professional meetings, presenting the V-Rod. If I remember correctly, DOT 5 is specified so it won't harm the paint. Some of the paint jobs are incredibly expensive. H-D owners are particularly anal about the appearance of their bikes!
BTW, it was one of the more interesting meetings. We invited the local H-D chapter members to the meeting. It was an interesting mix of suits and leather!
BTW, it was one of the more interesting meetings. We invited the local H-D chapter members to the meeting. It was an interesting mix of suits and leather!
I am very anal about my preventive maint. I have never changed out my brake fluid in any of my cars. My wife drives a 2001 Lexus RX300, it has 128k miles on it. I replaced the original brake pads at 89k miles. To this day, my fluid is just like new in color, and has no moisture in it with a tester. So what gives?? I would love to change it, but I feel it is ok still.
If you want to change without a good reason, go ahead. I would wait for the next pad change and at that time rebuild/replace the calipers. That will leave you with fresh fluid/lube in all of the caliper plus new rubber seals and boots. Changing fluid is a poor substitute for replacing aged, worn rubber parts.
its a 97 civic dxquote:
Originally posted by sxg6:
what year civic is this? im very skeptical.. it probably just says to check the fluid level..
Maybe it's just me...
Brakes are such a vital safety feature, and changing the fluid is so easy (and cheap if you pay to have it done), I can't believe this is even being debated
Is saving like $30 every other year (or an hour of your time) worth the risk, however small?
Brakes are such a vital safety feature, and changing the fluid is so easy (and cheap if you pay to have it done), I can't believe this is even being debated
Is saving like $30 every other year (or an hour of your time) worth the risk, however small?
Kestas
Staff member
It's not you, but everyone on the board. We're only debating this because one (maybe two) people don't agree with the rest.
Just get some speedbleeders and some ATE Typ 900. Gives you something to do when your trying an extended OCI and you have the "must change my oil now" itch.
Some cars you can even setup the bleeders without taking off the wheels.
I do mine after every track event, or half way through an autox season. (Every 6 months) Super clean brake system here!
Some cars you can even setup the bleeders without taking off the wheels.
I do mine after every track event, or half way through an autox season. (Every 6 months) Super clean brake system here!
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