My '02 Prius is up above 225k miles, and the time has come to flush the brake fluid, and I plan on doing this at home without any of the special tools (other than a hose w/ a one-way valve). She's been on a DOT4 diet since at least 2010. And I believe this is the first total flush. I would like to change her over to DOT5. Is this okay to do without replacing the parts? I know the various versions shouldn't be mixed, and I'm not sure if flushing the system ACTUALLY removes/displaces all of the old stuff. Should I just be happy with 5.1, or stick with 4?
You probably won't notice much difference moving to 5.1 I'm sure some here are going to tell you it's not recommended for the system I have one of these cars well a generation two with purple silicone in it and it works just fine but that's another story The dot four is actually pretty good so you can just drain and refill for the most part but if you want to flush I guess you certainly can notice that you're reservoir is still for the most part clear it's not turned black etc because that fluid and the seals don't interact like it used to so you should be in pretty good shape internally is the point
I'm not a mechanic, but as I understand it, getting any air in the ABS system requires a rather complicated procedure to bleed out.
You don't want DOT 5. It's hard to switch a car to that stuff even when the car has a simple brake system, and the Prius is just about the most sophisticated brake system on public roads. When you switch from a glycol-base to a silicone base you need to remove every trace of the outgoing fluid. Disassemble everything, blow air through it, thoroughly dry it for days type stuff. ...and that's assuming all the seals in there are still okay with a silicone-base fluid. Some may need to be replaced, and if they're shaped any weirder than an o-ring I don't know where you'd even find the item. Stick with DOT 3 or 4 glycol based fluid. The anti-boil safety margin you get from converting to DOT 5 is not something you get close to on the street anyway.
Hello, re flushing brake fluid in Gen 1 Prius with Dot3 fluid. It’s been 11 years since it was done at a Toyota dealer, and I’m wondering if I should leave well enough alone, because I see in the service manual at the end of the complicated step by step process, a special tool is required to turn the SRRR solenoid on and off. Brakes are working fine of course. How can a flush be done without this special tool, and of course I would be careful not to allow air to get into the system via the reservoir?
Do it by gravity open a bleed screw. Watch till fluid is emptying out in resvoir. As it begins to run out pour the new stuff in res. Keep letting it drip .. wen that sides dripping clean new fluid . Close and crack other side . Let it run till clean new shoes on paper towel . For the someone in car pushing pedal till it runs clean
I changed the brake fluid myself. It's simple. I did it this way. - I drained the old fluid from the reservoir and filled it up to the cap with new fluid. - I started with the rear wheels. It doesn't matter if it's left or right first. There's only one tube going to the rear, which splits to the rear wheels with a T-connector, just like in old cars. - I opened the bleeder screw on the rear caliper (you have drum brakes in the US, right?), connected the bottle with the tube. And now for the most important part. With the ignition on, I gently pressed the brake pedal harder and harder until the electric pump under the hood activated (you can hear a slight humming sound). I held the pedal in this position for about 20 seconds to thoroughly flush the system, remembering to keep an eye on the reservoir. Never press the pedal all the way to the floor, as this will trigger a low-pressure error in the brake system. (The error message popped up once, so I quickly turned the ignition off and on again, so it didn't register.) - I did the second rear wheel in the same way, but in a much shorter time, max. 10 seconds (there was fluid remaining from the T-connector to the caliper). - I did the front brakes using the traditional method (the electric pump is connected only to the rear wheels), i.e., I pumped the brake pedal, but remembering not to press the pedal all the way to the floor to avoid an error. Personally, I think that changing the fluid doesn't require following the same order as bleeding the brakes. Regarding brake fluid selection: DOT3 maintains its performance the longest (it absorbs water from the air the slowest and also has a lesser effect on lowering the fluid's boiling point). DOT4/DOT4+ is a compromise between efficiency (high fluid boiling point) and durability. [*] DOT5.1 offers high performance at the expense of durability (DOT5.1 loses its performance quickly and requires frequent replacement). DOT5 is a silicone-based fluid, not a glycol-based fluid. It doesn't mix with previously used fluids and requires thorough flushing of any old fluid from the system. In theory, it's a good fluid with very long durability, but due to its tendency to foam, it's not suitable for cars with ABS. [*] The difference between DOT4 and DOT4+ (or DOT4hl) is viscosity. DOT4+ has a lower viscosity, similar to DOT3, which allows ESP systems, etc., to function better. (This is one of the reasons why DOT3 was used in new cars for so long instead of DOT4. Only after the development of DOT4+ did manufacturers abandon DOT3.) Personally, I would choose DOT3 or 4. DOT5.1 makes no sense in a Prius.
