Question about long tube method of brake bleeding |
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Question about long tube method of brake bleeding |
computers4kids |
Nov 26 2011, 10:42 AM
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#1
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Love these little cars! Group: Members Posts: 2,443 Joined: 11-June 05 From: Port Townsend, WA Member No.: 4,253 Region Association: None |
I have some air trapped in my brakes and want to try the long tube method to purge. With the tubes in the resevoir and connected to each caliper nipple, I understand the idea of cracking each nippple open and pumping until the cows come come.
What puzzles me is the idea of injecting air back into the system using this method. Until the lines are full of fluid, won't you be sucking air on each pump of the brakes back throuh the nipple from the empty tubes? I have a motive bleeder but can't seem to get all the air out. It takes a couple pumps to get a hard pedal. New MC All new rebuilt calipers, etc Used the pedal pump and release method Flushed a 1/2 gallon of fluid throuh the calipers Rear vented to .004 Driven the car and repeated the bleeding with motive and two people Yes, the front caliper nipples are pointed up No speed bleeders (IMG:http://www.914world.com/bbs2/uploads/post-419-1182989448.jpg) |
andys |
Nov 26 2011, 01:30 PM
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#2
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Advanced Member Group: Members Posts: 2,165 Joined: 21-May 03 From: Valencia, CA Member No.: 721 Region Association: None |
Though there are a couple of methods that work well, my personal favorite is reverse bleeding. You can only do this when the calipers have both an upper and a lower bleed port as typically found on race calipers, since you will need to use the bottom port (lowest in the system) to push new fluid into the system. Start with the caliper that's furthest from the master typically starting with the rear circuit. The reserviors of course need to be free of fluid, and you'll likely need to remove some fluid as you go. It's best to perform the procedure again the next morning to ensure all the air is purged.
For systems with traditional caliper bleed port locations and small reservoirs, the pump and bleed method seems to work reasonably well for me, but you have to be thorough. After I think I'm done, I'll do it some more. On my hydraulic clutch (V8 conversion car), it took me no less that four tries over the course of a week to get all the (damned) air out....that ended-up being far more tedious than the brakes. Bet I purged a good 1/2 litre or more through it. Andys |
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