Comparing brake fluid flush methods

I do the same - in Ft Myers, Florida - which is definitely NOT a dry area. I do this every 3 years, regardless of whether the experts here say that I need to or not. I have also upgraded to Speed Bleeders, but don't find them to be *that* much easier than the old; pump it, crack it, close it, method.

 

Following up on this thread.

I successfully completed the brake fluid flush on my truck. The back story is that I had replaced my brake pads and rotors but was not entirely happy with the results. The brakes seemed spongy and not as effective. I reasoned that the new pads (not Toyota brand) could be responsible for the slight decrease in braking but not the sponginess. So that's when I decided to do a brake fluid replacement which had never been done.

Sure enough. The brake fluid flush revealed much air bubbles in the system. As I was bleeding the first wheel, the rear right, the old fluid came out for a while and then bubbles began to appear. The bubbles did not cease until I had run about a quart of fluid. I'm assuming the bubbles came from either the master cylinder or the ABS module. My brakes now come on firm and hard.

So that begs the question, how did that air get in there? The only thing ever done to the brakes was the pad/rotor swap and the brake fluid had never run low. Could it be some kind of seepage over time? Or was the air always there and I just never knew it?

 

I've worked on my own brakes for decades and I've never had air show up in the brake system from changing pads and/or rotors. I have had it show up anytime I had to break the brake lines apart to do something like replace the master cylinder or calipers.

I only use the Motive bleeder system now. I used the "get a friend to push the pedal while you bleed" method for years. I've also gravity bled brakes. More than once I've really struggled to get the last bit of air out of the system....and even a little air makes a huge difference.

Bought the Motive system and never looked back. I have both built my own adapters when needed or used the ones Motive sells at times. I've done many vehicles and never been disappointed with the results. On my Tacoma, I actually didn't need to do any brake work, but I did use the Motive system to completely change my brake fluid as part of a "Replace every fluid in the truck" project last winter. Worked great, just like I knew it would....'cause it always does.

 

Aside from the crude joke, was it even remotely spongy before the swap? What method did you use to bleed/flush? In the past, I found that vacuum bleeding sometimes allowed air into the stream, but the air was entering the stream at the bleeder rather than actually being in the fluid (which is why I started pressure bleeding since). If it WAS in the fluid, and it took that long, I would suspect it was in the ABS module, though I wouldn't be able to explain how it got there without knowing the history of the car/brake hydraulics.

As far as I know, if it was in the master, it would have felt spongy this whole time, whereas I have heard of situation where air was in the ABS and things "felt" fine - though I have no personal experience. If you don't have a bidirectional tool, you can find a muddy or snowy area (obviously not this time of year) and purposely trigger the ABS to "bleed" any air out. I have never tried that method myself (I have an Autel scan tool), but my understanding is that it's a great way to "manually" do it.

 

That's the odd part. I never noticed it before but I was still on the original pads/rotors. I'm thinking those original pads had more "bite" and the sponginess was already there but the extra bite made it not as noticeable. Only when I installed these new ceramic pads with less-than-optimal braking did I really start to scrutinize it.

I used my Motive pressure bleeder and I'm glad I did because it allowed me to see/monitor the air bubbles better and be more confident in the flush.