The 30k service calls for a brake fluid flush. I had my dealer do it while they were replacing the transmission. Anyone know why this needs to be done at 30k and 10 months? Anybody else have this done?
That's actually why hygroscopic fluid is used. If water got into the brakes system and didn't mix with the fluid, it would boil at 212F. As it is, it mixes with the brake fluid and only slightly depresses it's boiling point.Brake fluid is hygroscopic, i.e. it absorbs water. Over time, this water absorption can lower the boiling point of the fluid. As we all know, water boils at 212 degrees F, whereas pure brake fluid typically won't boil until it reaches over 400 degrees F...
Unless you're over 30,000 miles already, I think it's too early for a change. But it won't hurt to change it early.I am thinking a brake fluid flush on an Ascent should be pretty simple. Does anyone know the recommended sequence or where I can find it? Thanks!
Good info.That's actually why hygroscopic fluid is used. If water got into the brakes system and didn't mix with the fluid, it would boil at 212F. As it is, it mixes with the brake fluid and only slightly depresses it's boiling point.
Years ago I had an experience with that very thing on a motorcycle running DOT5 (silicone, not miscible with water). Lost the front brake when it heated up and the lever just went to the bar. Fortunately I had enough space to run out and use the rear brake to not crash.
I am away so I can't verify myself, but I would first look on the power steering reservoir cap. I suspect that will tell you for sure.Page 456 says never mix DOT 3 and DOT 4 brake fluids, then page 489 lists both types as compatible.
My question is which fluid comes from the factory so I can replace it with the same?
HA. Funny that I have that sitting in my Amazon cart already for my Bimmer. I'll be doing all 3 of our vehicles as soon as the weather cooperates. I'll add another to the cart!
There's no need to pump the brakes, anyone can buy their own pressurized brake bleeder for under $60. This is the one I've used for many successful brake jobs over the past decades.Brake fluid is contaminated by more than just moisture while in use. Maybe you notice older cars have what looks like dark fluid in the master cylinder. That's contaminatin from rubber seals breaking down. Personally, I think more harm us caused by home mechanics doing their own brake flush than is gained with having fresh fluid because they usually do the flush by pumping brakes and over using the stroke of the master cylinder. Moisture is probably near the cap since it's vented. Rust or corrosion is also concentrated at that area just beyond the working stroke of the cylinder's piston. Pumping the brakes to flush causes seals to wipe this portion of the master cylinder and either wear on it or tear it outright. When that happens, a rebuild of the master cylinder will be required. Either that or replacement outright. Either let a ship do it using a pressure feed of fluid to the master, where the calipers are opened and a lot of fluid is allowed to flow without pumping brakes, or leave well enough alone until signs of brake fade Indicate service is actually needed.
I just completed the replacing the brake fluid at 28,000. Nothing wrong with my brakes but 30,000 was coming up and my dealer had 25% off. "The primary reason brake fluid should be flushed periodically is because it is a hygroscopic fluid, meaning that it readily absorbs and retains moisture. Though this might seem a bit odd at first glance, that is exactly what we want the brake fluid to do. With the understanding that many of the brake system components are made from metal, we can quickly see that moisture is the enemy. Brake fluid, by absorbing any moisture that gets into the system and retaining it, helps to prevent moisture related corrosion and failure of internal brake system components. Even the highest quality brake fluid can only retain so much moisture, however, so it periodically must be flushed from the system and replaced with new fluid. "The 30k service calls for a brake fluid flush. I had my dealer do it while they were replacing the transmission. Anyone know why this needs to be done at 30k and 10 months? Anybody else have this done?