How to change brake fluid?

[gooffeyguy]

Do you have hydro boost?

Yes In my 02 mustang, but my 95 and 33 doesn't.

 

[rockola1971]

I thought the standard ABS module was simply a bank a solenoids that pulsed opened to relieve pressure from the locked corner(s). I never knew it pumped anything. I know the StabiliTrak version of ABS has a pump on it because it actively applies pressure to some corners while relieving pressure from others. My questioning isn't to doubt you. I'm just kinda fascinated cuz I've never heard of this, but also never looked into it much.

After some reading, I see that the pumping action is a part of modern-day standard ABS since it has to reapply brake pressure to the wheel(s) it is modulating.

View attachment 370309

Every ABS system ive ever seen has an electric hydraulic pump. The ABS pump actually takes place of your Master Cylinder when called upon by the ABS computer. It pulses 12v to the ABS pump as needed and the solenoid controlled ABS manifold directs brake pressure and cuts it off as needed to each corner of the vehicle like you described. Cool fact...ABS systems actually came from Military Jets and were in those many many years before they were ever to be designed into automotive applications. The F-14 Tomcat and F/A18 Hornet both had ABS. The Tomcat came out in 1971 and the Hornet 1983. Im not sure how far back the ABS hit the military jets since I was only familar with the Tomcat and Hornet (Pre Super Hornet models) during my military time.TA

 

[rockola1971]

Do you have hydro boost?

I do on my 05 Denali. Pretty cool system until it leaks at the Hydroboost and has to be replaced.

 

[gooffeyguy]

Well duh, if you slammed on the brakes in a jet you'd fall from the sky, lol. With abs you'd slow down quickly but still stay in the air

 

[rockola1971]

Well duh, if you slammed on the brakes in a jet you'd fall from the sky, lol. With abs you'd slow down quickly but still stay in the air

Or just for those wet/icey Aircraft Carrier decks and wet or icey Air Station runways. Lock em up in the arctic region and you are done.

 

[swathdiver]

It surprises me how much fluid it takes, especially since the brake lines are rather small diameter and the reservoir doesn't hold a lot. The ABS modual and MC/Booster must have large passages or something.

Or more likely we were just knuckleheads! After rebuilding/replacing all the calipers I tried the gravity bleed method with the cups with fluid and hoses running into them at each corner. When that didn't seem to work we bled them the traditional way first and then with the Tech-2 for the ABS portion and that's where we really went through most of it.

 

[JamesLond]

Or more likely we were just knuckleheads! After rebuilding/replacing all the calipers I tried the gravity bleed method with the cups with fluid and hoses running into them at each corner. When that didn't seem to work we bled them the traditional way first and then with the Tech-2 for the ABS portion and that's where we really went through most of it.

Ok. A lot's been said so far in this thread and the message I'm starting to glean is I'm not gonna be able to get the old fluid out w/o the Tech-2.

I can accept I won't be able to get the ABS cleaned out, but is it going to be a waste of time to try to force out the old fluid by just cracking the bleeder and pumping the peddle?

6 quarts of fluid is just nuts to me. Especially since I had to do an oil change prior that took 4.

 

[Rocket Man]

Or more likely we were just knuckleheads! After rebuilding/replacing all the calipers I tried the gravity bleed method with the cups with fluid and hoses running into them at each corner. When that didn't seem to work we bled them the traditional way first and then with the Tech-2 for the ABS portion and that's where we really went through most of it.

When I did mine, I didn’t do the ABS bleed. I used a Motive pressure bleeder. And I went through a gallon of fluid even without doing the ABS so you weren’t too far off from what I experienced.

 

[Rocket Man]

Ok. A lot's been said so far in this thread and the message I'm starting to glean is I'm not gonna be able to get the old fluid out w/o the Tech-2.

I can accept I won't be able to get the ABS cleaned out, but is it going to be a waste of time to try to force out the old fluid by just cracking the bleeder and pumping the peddle?

6 quarts of fluid is just nuts to me. Especially since I had to do an oil change prior that took 4.

Yes you can, I did. And I believe if you don’t activate the ABS braking, in other words you don’t get into a situation where you have to jam the brakes so hard that the ABS comes on, that fluid never mixes with the other fluid. I could be wrong but mine still looks real clean after a year or more.

 

[rockola1971]

Ok. A lot's been said so far in this thread and the message I'm starting to glean is I'm not gonna be able to get the old fluid out w/o the Tech-2.

I can accept I won't be able to get the ABS cleaned out, but is it going to be a waste of time to try to force out the old fluid by just cracking the bleeder and pumping the peddle?

6 quarts of fluid is just nuts to me. Especially since I had to do an oil change prior that took 4.

You can get the old fluid out. The problem comes in when air gets into the system up to and past the ABS manifold. Then it can be quite difficult to get ALL the air out without at bidrectional scanner like the Tech II. There are other brands/models out there that also have this function too so you are not limited to the Tech II but Ill tell you from my personal experience that my Tech II clone has done everything ive ever needed for troubleshooting and procedures and then some. Im sure there is stuff in it that I havent even discovered that I will need it for. Unfortunately the Tech II is only good for up to around 2009(Can vary by model vehicle as to cutoff year) IIRC after that a different protocol scanner is required.