Posted by Clint Dixon [172.68.58.86] on Saturday, May 05, 2018 at 10:45:09 :
In Reply to: Need some thoughts on Brake problem posted by Kevin in Ohio [172.68.58.200] on Friday, May 04, 2018 at 11:52:00 :
Hi Kevin.
Okay, we have heard two different theories: to start bleeding at the left rear wheel first because it is the furthest from the master cylinder, and the right rear wheel first. I do not start at either one of those. I start at the wheel cylinder closest to the master cylinder, and I have a reason for doing it that way.
If you start at the furthest from the master cylinder, you have three other lines that tee off of that line along its length (between master and wheel cylinders). If you bleed the furthest first, some of the fluid in the line can leak into the three other lines that tee off along its length, especially if those lines are dry. What happens when a drop or two of fluid enters those lines? A bubble of air can replace it and enter into the line furthest from the master cylinder. Even if no fluid happens to enter those other three lines, air can be drawn in from them just from the venturi effect of the fluid passing buy those empty lines.
By starting at the closest to the master cylinder, you eliminate each completed line being a source of air bubbles as you work your way further away.
I had the same problem you are experiencing when I used to do it following the commonly accepted method of "furthest first". Once I switched to "closest first", the job got a lot easier and when the air bubbles stop - they stop - instead of slowly fizzling out.
Also, I purchased a set of new brake shoes which which had the linings only riveted but not glued to the shoes. Between one pair of rivets to the next, there was about .050 of an inch of clearance between the lining and shoe. The lining was like a roller coaster - down at the rivets, up between them, and back down at the next pair. They were impossible to adjust correctly as the humps in the linings were acting like springs against the drums. This problem was not creating additional air in the lines but I could get no pedal. I also worked on a friends truck where there was way too much heal contact. The shoes had to flex a whole lot for the toe to contact. In this case, the whole shoe was acting line a giant spring against the drum and again - no pedal.
Keep us posted.
Junior
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