Brake Fluid Flush

[dachrist]

I'm changing out my lines to SS and want to do a complete brake fluid flush. My questions are:

1. Which kind of brake fluid? DOT3 or DOT4? I know DOT3 is factory, but I've heard that DOT4 is a better overall fluid. I've also heard that it can cause issues with our ABS sensors?

2. Should I try to suck out some of the old brake fluid out of the master cylinder with a turkey baster before I start with the new fluid?

 

[dachrist]

Nobody has an opinion on this??

 

[grimm]

You would be fine using DOT 4. The DOT 4 is basically the same chemical make-up as the DOT 3, since they are both glycol based, but with added glycol esters to increase the wet/dry boiling point of the fluid. The DOT 4 should have no effect on the ABS sensors. However, if you don't bleed correctly, you may trap air in the ABS pump which could cause some malfunctions, but that is the case with either choice of brake fluid. Hope this helps.

---------- Post added at 04:30 PM ---------- Previous post was at 04:09 PM ----------

Oh, and to answer your turkey baster question, which I missed, I would just leave the old fluid because if you drop the fluid too low, you could potentially get air in your system which would lengthen the time it would take have your brakes properly bled. The old fluid will make it out eventually anyways.

 

[dachrist]

Thanks for the reply. As for the baster what I meant was removing about half of the old stuff in the reservoir before adding the new stuff.

Also, you mention about bleeding correctly, otherwise I will get air in the ABS pump? I assumed the proper approach was the 2 man method, IE one in the cab pumping the brakes, hold, I release the bleeder at the wheel cylinder/caliper, foot to floor, hold, I tighten bleeder, repeat until clear fluid comes out of the bleeder. Start at right rear, then left rear, then right front, then left front. Is there a different way with respect to the ABS pump?

 

[faze]

You're right on how to do it...start with the furthest wheel and move to the closest...two person job. You could suck some old stuff out of the reservoir and replace with new...won't hurt anything.

If you're helper does pull back and you get air into a line you just have to go back to the furtherest away and start over...no biggie, just more fluid.

You probably know this stuff can eat paint but thought I'd mention it anyway

 

[grimm]

Thanks for the reply. As for the baster what I meant was removing about half of the old stuff in the reservoir before adding the new stuff.

Also, you mention about bleeding correctly, otherwise I will get air in the ABS pump? I assumed the proper approach was the 2 man method, IE one in the cab pumping the brakes, hold, I release the bleeder at the wheel cylinder/caliper, foot to floor, hold, I tighten bleeder, repeat until clear fluid comes out of the bleeder. Start at right rear, then left rear, then right front, then left front. Is there a different way with respect to the ABS pump?

I knew what you meant. What I meant was if the fluid in the reservoir drops too low, you can potentially have air enter the system that way. It's easier, in my opinion to not even bother trying to remove any from the reservoir, since the old fluid will pass through eventually.

And you are correct on how to bleed. However, with the ABS system, there is typically a valve that actuates the ABS, known altogether as the ABS pump which needs to also be air free, and more often than not, can not be bled without taking proper measures. (e.g. having the vehicle on jack stands, getting the wheels to move and "locking them up" signaling the ABS to kick in, thus actuating the pump and cycling fluid and proceeding from there.

Anyways, hope this helps, good luck.

 

[992dr]

Speed bleeders are your friend.
Bleeding your brakes is a one man job with these.
http://www.speedbleeder.com/

 

[dachrist]

Last question, how much brake fluid will I need for the entire system? How many quarts?

 

[MotRhead]

sorry to hijack but has anyone ever tried that speed bleeder? is it just self bleeding?