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This may be lengthy, but I’m going to provide as much info as possible.
I have a 1993 Honda Civic dx. I upgraded my brakes to 94 Legend Gs calipers, 91 Civic Ex 15/16 master cylinder, stainless steel brake lines, and rear disc conversion with the 40/40 proportioning valve. One issue I may have (literally just found out) is that the bleeder valve on the Legend calipers is facing down toward the ground and not up toward the sky. I’m not sure if that will cause issues with bleeding the brakes or not. I can flip the calipers to the other side if that is the issue.
Anyway, when I pump the brake pedal with the engine off, I slowly build pressure. When I release the pedal it immediately loses pressure and I have to pump the brakes again. With the engine running I have no pedal pressure at all. I can pump the brakes all I want and there is never any pedal pressure. I have bled my brakes a few times. A couple times with a buddy and once by myself. I followed Eric’s video of him changing the fluid on his Subaru alone. However, I also realized when I was bleeding them by myself. I left the master cylinder cap off, could that have any effect? I have checked all the brake lines from the calipers, up to the proportioning valve and the master cylinder. I cannot see any leaks and when I let the vehicle sit for a couple days the fluid level is the same and there isn’t any signs of fluid leaking from anywhere. I’m assuming there is still a lot of air in the lines. I did also bench bleed the master cylinder.
The image I attached is unfortunately not of my car (I wish I could afford a 5 lug swap haha), but I hope it serves as reference. This shows the bleeder valve facing up.
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One issue I may have (literally just found out) is that the bleeder valve on the Legend calipers is facing down toward the ground and not up toward the sky. I’m not sure if that will cause issues with bleeding the brakes or not. I can flip the calipers to the other side if that is the issue.
Based on Pascal’s law, you should be able to bleed your brakes upside down & sideways because hydraulic pressure is equal in all directions:
[i]
Pascal’s law or the principle of transmission of fluid-pressure (also Pascal’s Principle[1][2][3]) is a principle in fluid mechanics that states that pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure variations (initial differences) remain the same[/i]I also realized when I was bleeding them by myself. I left the master cylinder cap off, could that have any effect?
Only if you have exhausted the supply of brake fluid in the reservoir; otherwise, there is no issue here. (Be advised that brake fluid is “hygroscopic” meaning it will pull moisture from the air; therefore, isolate brake fluid from the atmosphere at the earliest convenience.)
I’m assuming there is still a lot of air in the lines.
Even if your brake lines contained 100% air this should all be depleted with just a few brake applications.
Anyway, when I pump the brake pedal with the engine off, I slowly build pressure. When I release the pedal it immediately loses pressure and I have to pump the brakes again. With the engine running I have no pedal pressure at all. I can pump the brakes all I want and there is never any pedal pressure.
Brake hydraulics are very straight forward. Your issue will fall into one of two categories:
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Internal leak[/u]: Your master cylinder is bad out of the box.. which unfortunately can more common than you think. (yes, this has happened to me)External leak: open bleeder valve, brake line connection, caliper piston, wheel cylinder can all be suspect. In any case, you would have seen brake fluid pee’ing all over the place by now.
This is all based on the assumption that the bleeding procedure has been performed correctly for your vehicle.
Honestly I’ve found one of the most useful things to do in this situation is just buy a couple 32 oz jugs of brake fluid and bleed the sh*t out of all 4 corners, do it way more than seems necessary and then do it some more! This can help too if the master cylinder wasn’t fully bled on the bench, it can slowly work the air out. Speed-bleeders help a lot if you can find ones that fit.
If the bleeders are facing down, you don’t have them on the correct side. That may be because of the placement of the calipers on the different vehicles. Sometimes the caliper is mounted toward the front of the vehicle, sometimes toward the back. There may be a difference between caliper placement on your vehicle, and the Legend.
Having the cap off won’t effect bleeding.
Given the amount of modifications you have, honestly it’s anyones goes what the problem is. However, you may find this helpful. I’d first see what I could do to properly bleed the brakes. I suggest you bleed at the lines instead of the bleeders. The reason they put the bleeders at the top is because that’s where the air collects. They way you have things set up, you may never get the air out.
You might also find this helpful.
http://www.ericthecarguy.com/faq/solving-brake-problems
Good luck and keep us posted.
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