Question about brake fluid changes + mystery wires

507 Views 11 Replies 8 Participants Last post by DanaH, 6 d ago

Paintbucketbrush

Discussion Starter · #1 · 10 d ago (Edited)

Hi there, i have 2 questions. The first is one I haven't seen asked in this forum (though I'm sure someone better at searching could find something), the second is a question I've seen asked but get contradictory responses.

Question 1: What are these wires on the brake fluid cap (circled below), and do they need to be connected to anything?

It kind of looks like they could mate with these others wires (see photo below). I'm trying to figure out whether I accidentally separated them without noticing while unscrewing the cap:

Automotive tire Motor vehicle Tread Fender Hood

Question 2: Why can't I just do the equivalent of a drain + fill of the brake fluid in the master cylinder, without bleeding the brake lines?

Some people say you need to bleed the brakes because there's no circulation in the brake lines, so the new stuff wouldn't actually mix. Other people say water sinks to the bottom of the lines and that's what you really need to get out.

Why, if there is no circulation in the brake lines, does the fluid in the master cylinder dirty over time? If there really is no circulation than it should stay clear, no?. That doesn't make sense to me. The water point I have no argument against, seems sound if that's actually what water does in a brake line. As you can probably guess I'm just trying to avoid removing my wheels and bleeding the lines because I rent and have no driveway/limited tools.

Thanks for the help!

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v4forever

· Registered

2000 EX 257,000 miles

Joined Feb 13, 2011

350 Posts

#3 · 10 d ago

Question 1 see above.
Question 2 brake fluid is hydroscopic and absorbs water just like a sponge.
Get a one way check valve in the picture and you can replace the fluid by yourself.
Just hook this device up, arrow on it points to the jar or bottle that the used fluid is going into and pump away on your brake pedal and fill your reservoir up.
Tip: Use a turkey baster type tool to suck out the old fluid from the master cylinder. Add fresh fluid from an unopened bottle of DOT 4. Then your sending fresh fluid into the lines and secondary cylinders.
Never let it run dry, if you do, take it in and get it professionally bled.

Motion pro brake bleeder check valve