Bleeding brakes: Where's the air?

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The Artist formerly known as Turbo84
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Clinging to my guns and religion in KCMO.
Just thinking about things while I've been bleeding the brakes (again). It looks like I've got the weep issue resolved at the junction block, and I'm just draining out expensive synthetic fluid at the moment. I'm just curious if there's any "scientific" way to narrow down which half (or corner) of the system has the air in it? I just hate doing things in a "brute force" way (ie: drain a lot of fluid out of every caliper bleeder, whether it actually has air in it or not).
Thoughts and opinions?
 
Ya got me Mike. All I know is that my Motive Power Pressure Bleeder is one of my favorite toys. I can usually do any car, and only waste a cup for all 4 corners.
 
What caliper do you have? If you really hate bleeding calipers, get some recirculator tubes 9or make them yourself), you may have to drill your calipers for them and add a recirculator valve. DPI has them, Also marketed under Sierra and possible Stewart (although I think Stewart components was bought by DPI)
 
What caliper do you have? If you really hate bleeding calipers, get some recirculator tubes 9or make them yourself), you may have to drill your calipers for them and add a recirculator valve. DPI has them, Also marketed under Sierra and possible Stewart (although I think Stewart components was bought by DPI)

Explain please. You talking some kind of closed loop with check valves?
 
Yes, self bleeding too.

sstop2install.jpg
 
What caliper do you have? If you really hate bleeding calipers, get some recirculator tubes 9or make them yourself), you may have to drill your calipers for them and add a recirculator valve. DPI has them, Also marketed under Sierra and possible Stewart (although I think Stewart components was bought by DPI)

I've got the Wilwood Dynalites. I was kicking around getting some speedbleeders (if anyone makes the odd small size that fits these calipers), and running a hose from the bleeder on back to the master cylinder, with some kind of filter (paint or coffee filter) to reuse the fluid. It's brand new fluid in the system, and I just have to otherwise find a way to dispose of the drained stuff.

Question: Why doesn't the junction block "system failure piston" move when one side of the system is opened up, and the pedal pushed to the floor? This lack of movement, does it mean that both sides (f/r) have air in them?
 
Well, finished pouring another quart of fluid through the system, and hot damn!, that pedal is stiffer'n shit. Looking forward to getting the tires back on and taking it for a ride.
 
Why waste fluid ??? I drain the fluid thru a clear plastic hose from the bleeder into a clean plastic container, after each caliper is done I filter it using a paper coffee filter (Melita works well) and pour it back into the bottle.... :huh:
 
Why waste fluid ??? I drain the fluid thru a clear plastic hose from the bleeder into a clean plastic container, after each caliper is done I filter it using a paper coffee filter (Melita works well) and pour it back into the bottle.... :huh:


NO NO

It's picking up water and crap as it goes through the system. As cheap as i am, i would never do that.
 
Why waste fluid ??? I drain the fluid thru a clear plastic hose from the bleeder into a clean plastic container, after each caliper is done I filter it using a paper coffee filter (Melita works well) and pour it back into the bottle.... :huh:


NO NO

It's picking up water and crap as it goes through the system. As cheap as i am, i would never do that.

I have to agree with Turtle on this one. B/F is cheap, and you live in the tropics.:sweat:
 
Why waste fluid ??? I drain the fluid thru a clear plastic hose from the bleeder into a clean plastic container, after each caliper is done I filter it using a paper coffee filter (Melita works well) and pour it back into the bottle.... :huh:


NO NO

It's picking up water and crap as it goes through the system. As cheap as i am, i would never do that.

I have to agree with Turtle on this one. B/F is cheap, and you live in the tropics.:sweat:

Well, ordinarily I would not reuse brake fluid (I agree on the water issue with "old" fluid). But most of the fluid in this system is only days or a week old. I've been removing lines and redoing the flares and seats, and pouring new fluid in again, only to find another weeper in that junction block. Thank goodness I believe I'm done with (brake) things for a while.
 
No, it's puddling the water in the deepest spot, the caliper bores causing all kinds of nastiness like rust. I'd rather have the hygroscopic DOT3,4,5.1 When it turns a darker brown you know it's time for new fluid. Gives better pedal feel too.
 
I was told that DOT5 silicone fluid does not absorb water like DOT3 fluid, is it not worth changing ? How does it affect the pedal feel? Should I better keep using DOT3?
 
I was told that DOT5 silicone fluid does not absorb water like DOT3 fluid, is it not worth changing ? How does it affect the pedal feel? Should I better keep using DOT3?

I would just use Valvoline Synthetic DOT 4. It's rated at 480*, and is $7 a bottle. Pressure bleed it every 2-3 years, and don't worry about it.
 
. Pressure bleed it every 2-3 years, and don't worry about it.


If you run track days. Change it before every event. Cheap insurance.

I can see that. I meant on the street.
I think if I ever try track, I'll get the Wilwoods and use DOT 5.1. Maybe ceramic pads.
I spent 10 hours in the driveway changing a C-5 brakes and shocks yesterday.
I noticed those ceramic pads stop NOW. I was also impressed that the rotors are all different parts. Lefts and right don't interchange. The vanes are angled the same when installed. I also like the front air ducts. I never realised they had them stock.
 
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