Brake Fluid Change

Well, after 3 years and over 36K miles, it's getting to be time for the car's first significant "maintenance" item: brake fluid replacement. Brake fluid is hygroscopic, so in the past it was a good idea to flush out the old and put in the new, bleeding each slave cylinder in the process. There was usually some gunk that had collected there that got flushed out in the process.

There are a number of techniques for doing this:

1. Simply open up the bleeder valve on each wheel in turn and pump the brake pedal until the fresh fluid starts coming out.
2. Do the same, but use a pressure pump to force fluid through the system rather than the brake pedal
3. Apply a vacuum at the brake bleeder to suck the fluid out
4. Simply open up all the bleeder valves (attach appropriate tubes to them) and let fresh fluid drool through the system.
5. Last year on my new used Sparrow, the only way I was finally able to bleed and then restore pressure to that vehicle's convoluted brake system was to pump fluid UP from the slave cylinders (after first flushing out they system).

One of the problems with pumping the brake pedal is that when it travels past its normal travel point the rubber in the master cylinder can now get roughed-up on an unused part of the cylinder - thus wearing it down prematurely.

Anyway, I was wondering what the latest thinking is on this rather mundane topic?

Also, what is considered the latest and greatest brake fluid to use, recognizing that our i-MiEV will probably never ever experience high brake temperatures because of our regen?

Where you live Joe, I think it would be plenty safe to go to 10 years and 100K miles before needing to replace brake fluid! :lol:

Have either of your cars got caught out in the rain yet??

Your method #4 should make an easy job of it - Leave the cap off the master and keep trickling new fluid in there so it never runs dry

Don

Still haven't changed the brake fluid in my three i-MiEVs... I recently came across a few discussions regarding the necessity of flushing the brake fluid, with manufacturer's recommendations being all over the map, and with Nissan Leaf's being particularly onerous (artificially short interval simply to get the cars into their service department?).

Here's one (recognizing it's self-serving by the manufacturer) -
http://www.brakebleeder.com/solutions/brake-fluid-testing/resources/new-test-stops-age-old-myth/

Recall the old bugaboo that depressing the pedal fully while flushing the system was actually really bad for the seals as they would now scrape over an area that normally had no use at all. Thus, care in system flushing and perhaps gravity feeding with minimal pumping is indicated.

Anyone have any experience with this or similar testing products?
http://www.brakebleeder.com/product-category/brake-fluid-testing/

Yes, when I took the car in for my last unsuccessful attempt to get a set of cv joints replaced on warranty due to vibration issues, I offered to pay for the brake fluid replacement (called for at 60k miles) and the mechanic said not to worry about it.. (service writer had the day off, he'd never say such a thing).. I don't think it's just a case of lazy mechanic, though he didn't even do a moisture test. Of course those moisture testers are controversial in their own right...

http://www.brake-eng.com/News/The-Dangers-of-Conductivity-Type-Brake-Fluid-Testers/

Does our brake fluid need the maintenance that ICE vehicles do? With the i-MiEV's regen, the brakes rarely get warm let alone hot, plus the fluid in the reservoir doesn't flow into the lines unless there's a leak.

I don't recall my Dad ever messing with the brake fluid in the Cavalier, and we owned that for 10 years (as far as I know, it's still on the road. It was traded in for a C-Max).

(Jay, I notice my CV joints rumble a bit under heavy acceleration, especially with some weight in the back. I still don't understand why they rumble, though. The axles are almost level.)

Thanks PV1, it's the fact that our brake fluid never heats up to drive out the water that concerned me, as the fluid absorbs humidity with each daily temperature cycle, not to mention my local wet climate.
I'll start a new thread on the CV rumble. We may be onto something.