Featured Are Brake Bleeds necessary?

Brake fluid is hygroscopic. That is a fancy term meaning it means it picks up moisture over time. The moisture can do damage to the expensive brake system parts as well as boil over in heavy brake use (think coming down a mountain without using B mode).

In other cars I've owned, I have seen 2 year brake fluid change intervals. In race cars, some sanctioning bodies require a brake system flush and fluid change before every race.

Don't recall what Toyota recommends.

When you drain and change the fluid, you bleed the brakes to get any air bubbles out of the system. Air compresses, the fluid doesn't. When you press the brake pedal, you want the fluid to squeeze the calipers applying the pads to the rotors. Not compress air.

 

Only when changing the fluid or otherwise having the sealed system(s) open to the air.

Or are you really asking if it is necessary to change out the old fluid ??

 

no, you don't need any services until 100,000 miles. just tires, oil, filters, inspections, lubrication until then.

 

there is no recommended bleed at 40k. where are you getting your maintenance information?

besides, we don't bleed them these days, we use leeches.

 

Details are important.

There is no such thing as a recommended "bleed"......at any time or mileage.

If you ask the right question you might get better answers.

 

OK so then you got the right answer here......from several different people......that a "brake bleed" is NEVER necessary as a routine maintenance procedure. It is only done in response to a brake problem or during other brake service where the fluid is replaced.

P.S. Whoever told you that a "bleed" was necessary routine maintenance is......mis-informed.
Or maybe is pulling your leg.

 

I would bleed the brakes every 90k miles or every 3-4 years as a preventative maintenance.

 

Brake fluid changes ARE necessary. More often in wet environments, less often in dry. "Bleeding" is only necessary if you get air or some other gas in the system, but is also -how- the fluid is changed. But you meant fluid changes.

If you don't believe this, then explain why rear calipers will "freeze" (corrode to no operation). They rust internally from the water absorbed by the brake fluid.
Yup. The system is "sealed".
Nope. You can't really seal it completely. The pistons move over the seal, which can often be soaking wet. -Some- water will always get in. It is adsorbed by the brake fluid (by design) and the concentration of water/brake fluid gravitates to the "lowest" part of the system, which is the rear caliper opposite side of the cars master cylinder. Which just happens to also be the one that usually "freezes" first. The water also lowers the boiling point of the brake fluid.

Probably not a big deal in a Prius, but a REALLY big deal in a larger vehicle or a race car. The fluid boils, and that vapour will compress, greatly reducing the pressure the calipers can apply to the disk.

Failing brakes will make for a really bad day!

 

really? please tell us more, i've never heard of doing this, thanks!

 

You must have @Mendel Leisk on ignore then.

 

am i confusing 'brake bleed' with 'brake fluid replacement'? i always thought bleeding was just a follow up whenever air is introduced to the system.

 

The only time I bleed the brakes is when doing brake work (replacing brake lines, etc). Pre-emptive brake fluid swapping is something a lot of people do, but I use the visual method. If the fluid is honey colored in the reservoir, it's time to swap fluids, which involves bleeding.

But I am definitely not a seasoned vet and up on all the lingo either.

 

agreed, it may be a failure to communicate. if it means fluid replacement, i would follow the o/m, and for those who like to practice more prentitive maintenance, follow mendel or nutz.
as for 40k, time might be a better indicator.

 

IMO Absolutely.
A bleed, the removal of air.
If you ever raced motorcycles, one may notice the air (softness) that can occur over a race (in addition to fluid heat/ fade.) You can get a bubble, a burp, if you bleed between races, improving brake feel.
,
A flush is another issue.
Here you are replacing the old "water infused" fluid with fresh fluid.
Every two years is the standard....ignoring individual manufacturers service guides.
Also note the importance of cold and hot oil boiling points of the replacement fluid.

Now a days, bleeds/ flushes have become more difficult because of ABS et al systems.
Many vehicles require a scanner or computer hooked up to the car to correctly do a brake fluid service.

However, many of the motoring public ignores brake fluid maintenance with no ill effects, complaints or even comments about braking performance.

Good luck in your decision.

 

prius brakes get so little use, i wouldn't compare them to motorcycle racing.
but if non use is detrimental to the system, that is a different story.
i sure wish we could define this discussion better.

 

We have 153 k miles on our 2010 Prius II and when I lubed the Caliper pins at 142 k miles, the pads were almost at 9 mm all around. I agree if you drive ahead and pay attention while driving, the brake system gets very little use.

So I have not swapped out the brake fluid, but maybe at the next Bay Area meetup that might be something to consider.

 

This is another instance where Toyota USA and Toyota Canada have different stances. TC Warranty and Maintenance Booklets (in pdf format) are a little harder to cadge (compared to the US manuals through Toyota Techinfo); the last I bothered to get is 2014. Note: the maintenance schedule section covers every Toyota vehicle, not just Prius.

Also, contrary to the US interval-by-interval format, the schedule is presented in graph form, which is only about 10,000% more empowering and easy to follow. Here's the bit about brake fluid replacement. I'll attach a pdf of the whole page too:



I've got a vague recollection they've shortened the interval even more, in later years, not sure. Also, just for a counterpoint: Honda Canada has been saying change the brake fluid tri-yearly, regardless of mileage. For decades, that I can recall.

I managed to do the brake fluid replacement last fall on our 2010 (dealership had done it before, in conjunction with the brake master cylinder recall, in 2013). @NutzAboutBolts video, the Repair Manual, a few very rudimentary tools*, and my wife pushing the brake pedal, we had no problems.

* Kirkland Mayo jar with hole drilled in the lid, vinyl tube with rubber coupler for bleed bolt, and a syringe with tube extension and thin spigot at the end.