How to flush brake fluid...

[demarpaint]

Originally Posted By: sasilverbullet
Originally Posted By: rustypigeon
Originally Posted By: Donald

Gravity is faster/easier than people think.


How long would it take to flush all 4 lines using gravity?

I have only done the pressure tank method and the helper push pedal method.


I'd like to know also...


I did my Liberty in less than an hour. I jacked all 4 wheels off the ground. I used a turkey baster and got as much brake fluid from the master cylinder as I could, and then filled it with fresh clean brake fluid to the top. I have 4 joint compound buckets cut to about 8" tall and slid them under all 4 rotors, and opened the bleeders, to slowly trickle brake fluid. I increased the flow, so that I was able to keep the master cylinder topped up without any problems. I ran a quart of fluid through. When I ran through almost the whole quart I over filled the master cylinder with the remaining brake fluid in the quart and closed the brake lines. I left the left front bleeder open until I had the fluid level to the full line and closed it. I loosened the rear bleeders first, then the fronts. The flow of the fluid with the bleeders almost fully open wasn't crazy, like I thought it might be.

 

[Ducked]

Originally Posted By: Garak
Originally Posted By: Donald
Gravity is faster/easier than people think.

Definitely. I had never bothered with it for years, then tried it with my G37 when I was stuck doing some work by myself. It worked exceedingly well.


Gravity works fine for changing fluid, though (unless you rig a U-tube, which probably isn't worth the trouble) you do have to keep an eye on the reservoir level.

If you've got, or get, air in the system, gravity isn't great at purging it.

That was my situation when I started using the syringe. Now I just use it for fluid changes as well, since I've got it, it gives me more control, and it places less demand on my attention span.

A syringe is also a bit better than gravity at flushing dirt from, say, wheel cylinders, but its still not very good, and perhaps nothing is.

 

[Garak]

Originally Posted By: sasilverbullet
I'd like to know also...

I'm not sure on every vehicle, of course, but with my G37, I couldn't even leave the master cylinder 5 minutes without topping it up. I just kept an eye on things and made sure I didn't have a disaster.

 

[DeepFriar]

Is it true or an urban myth that the fluid nearest to the brake surface is never really replaced? In other words does the caliper hold on to fluid that is not replaced in a normal flush? Don't know where I heard that.

 

[Garak]

I would say that's true, given that the bleed screws aren't exactly the last point on a single piece of plumbing. Now, one might argue that there is diffusion in the fluid, so changing on a regular interval evens things out, as it were. But, trying to do an absolutely complete flush without replacing some hardware would be problematic.

On the G37, I replaced the calipers. If I hadn't, I'm not sure how I would have gotten all the old fluid out of the calipers.

 

[Ducked]

Originally Posted By: Garak
I would say that's true, given that the bleed screws aren't exactly the last point on a single piece of plumbing. Now, one might argue that there is diffusion in the fluid, so changing on a regular interval evens things out, as it were. But, trying to do an absolutely complete flush without replacing some hardware would be problematic.

On the G37, I replaced the calipers. If I hadn't, I'm not sure how I would have gotten all the old fluid out of the calipers.


This caliper and wheel cylinder had both been pressure flushed with a syringe and the system fluid changed several times in the six months before they were stripped. I can't say for sure that the fluid isn't changed, but since they both eventually flushed apparently clean, its a fair bet that flushing doesn't remove everything.

 

[DoubleWasp]

Originally Posted By: HosteenJorje
Some of the early ABS systems had pressure accumulators that required special equipment to bleed the system, but I don't think the ABS systems today require any special procedure.


Oh, they do.

But only if air is introduced ahead of the ABS pump.

 

[DoubleWasp]

These days I stick to my Motive brake bleeder. Works like magic every time.

 

[slybunda]

I have a pressure bleeder a sealey one. It works great on euro cars that have a threadded cap on the reservoir but i cant use it on some [censored] cars that have non threadded push cap. Any way around this?

 

[cjcride]

The Motive Pressure Bleeder has adapters for different car models. Google it, you may be able to fashion your own.

 

[George7941]

To second cjcride's post, pressure brake bleeder adapters are widely and easily available from many manufacturers and they can be hooked up to your bleeder.

 

[Falcon_LS]

I have Speed Bleeders on all my cars, which makes it very easy and I get to control how far the brake pedal is pressed down. Failing that, I gravity bleed and make sure the reservoir is topped up.

 

[seanf]

Motive power bleeder is the way to go, I did my Audi yesterday, it worked great except for the old reservoir cracking and blowing a hole in the back of it. I didnt realize at the time it had a pin hole which is probably why my brake fluid was gross and brown.