Hello all,
1991 Subaru Loyale 4x4 wagonI just did a bunch of front-end work that required removing the brake calipers. After hooking everything back up, I keep getting air in the brake system at all four wheels when I bleed the brakes. I bleed them until there's no air, then come back a couple of minutes later and there's air again. I bled them diagonally, as the shop manual instructed. I haven't bled the master cylinder yet because the bolts on the brake lines are a major PITA to get loose and, more importantly, the more I work on this, the more convinced I am that air is getting in.
The thing that has me thinking this is that I have bled enough air out of the system over the last three days to fill the entire system at least once, no kidding, not to mention the quart of fluid I have put through it. I can't imagine that much air could be trapped in there. My understanding of hydraulic systems is that air can get trapped and compromise the system, but I have a continuous supply of air bleeding out. At some point the air has to stop coming out if air is not getting in, even if an air pocket remains trapped in the system.
Two thoughts: 1) I replaced the copper sealing washers on the banjo bolts where the brake lines connects to the front calipers. I couldn't remember for sure, but I thought that one washer went on each side of the banjo bolt. Any chance that could be wrong? 2) Maybe it's just a strange coincidence and the master cylinder has a leak. I haven't found any visible leaks so far. Any thoughts or, better yet, does anyone know how to test this? I'm curious to know what other people think.