Does thus sound like good method to bleed modulator?
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04-08-2013, 02:04 PM
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Does thus sound like good method to bleed modulator?
To start, should I have engine running for brakes power assist, or can I bleed modulator without a running engine? I think running engine best, right?
After doing work on modulator, such as just changing shuttle valve seals, a Land Rover technician told me that one should bleed at the modulator. Modulator has two inputs from the master cylinder, and four outputs, two for front and two for rear brakes. In the old days, we had just one line to front and one to rear, but we now see two for both front and rear, in event one should break loose, leak, etc., we still have a backup line to avoid complete failure. Ok, how does this sound for bleeding at modulator: a. Pump brake pedal 5 times, and hold it down. open the FIRST in line brake line at modulator top, let it bleed for a bit, tighten it up again, all the time while having the pedal held down. Now, while pedal is still down, open second brake line, let it bleed out, close it. Repeat same thing for brake line three and four. ALWAYS KEEPING WATCH OF THE BRAKE FLUID LEVEL IN MASTER CYLINDER, DURING THIS WHOLE PROCEDURE, AND FILLING WHEN NECESSARY, SO IT NEVER RUNS LOW, WHICH WOULD PUMP MORE AIR INTO SYSTEM. b. Pump brake pedal five times again, and hold it down again. Open the SECOND in line brake line, let it bleed a bit before closing it shut, now do the same for line three, four, and back to one, all while holding that brake pedal down. Repeat process again, pumping brake pedal 5 times; this time opening, bleeding, and closing third brake line, followed by all other lines. Finally do it one last time, pump brake pedal 5 times, hold pedal down, open, bleed, close line four, followed by all other of the four lines. If this isn't best way to bleed at modulator, please tell me what method is better.
Once that is all done, I would no doubt bleed at the brakes, starting with right rear, moving to left rear, moving to right front, and ending with left front.
I have read, on this site, and heard some shade tree mechanics speak about using gravity feed method of bleeding brakes, which is complete bunk. There is no such thing as gravity feed bleeding of brakes. One has to hydraulically force trapped air out of the lines, and depending on gravity feed to do it, while drinking beer, simply does not do it. If you think I am wrong, let me know.
After doing work on modulator, such as just changing shuttle valve seals, a Land Rover technician told me that one should bleed at the modulator. Modulator has two inputs from the master cylinder, and four outputs, two for front and two for rear brakes. In the old days, we had just one line to front and one to rear, but we now see two for both front and rear, in event one should break loose, leak, etc., we still have a backup line to avoid complete failure. Ok, how does this sound for bleeding at modulator: a. Pump brake pedal 5 times, and hold it down. open the FIRST in line brake line at modulator top, let it bleed for a bit, tighten it up again, all the time while having the pedal held down. Now, while pedal is still down, open second brake line, let it bleed out, close it. Repeat same thing for brake line three and four. ALWAYS KEEPING WATCH OF THE BRAKE FLUID LEVEL IN MASTER CYLINDER, DURING THIS WHOLE PROCEDURE, AND FILLING WHEN NECESSARY, SO IT NEVER RUNS LOW, WHICH WOULD PUMP MORE AIR INTO SYSTEM. b. Pump brake pedal five times again, and hold it down again. Open the SECOND in line brake line, let it bleed a bit before closing it shut, now do the same for line three, four, and back to one, all while holding that brake pedal down. Repeat process again, pumping brake pedal 5 times; this time opening, bleeding, and closing third brake line, followed by all other lines. Finally do it one last time, pump brake pedal 5 times, hold pedal down, open, bleed, close line four, followed by all other of the four lines. If this isn't best way to bleed at modulator, please tell me what method is better.
Once that is all done, I would no doubt bleed at the brakes, starting with right rear, moving to left rear, moving to right front, and ending with left front.
I have read, on this site, and heard some shade tree mechanics speak about using gravity feed method of bleeding brakes, which is complete bunk. There is no such thing as gravity feed bleeding of brakes. One has to hydraulically force trapped air out of the lines, and depending on gravity feed to do it, while drinking beer, simply does not do it. If you think I am wrong, let me know.
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