Brake system problem. 2003 Civic Si
 

Recently I took every rim off along with every caliper. I took these to get powder coated which in turn only had the rims powdered cause he didn't want to disassemble the calipers for the heat process and neither did I so I left them alone.

After getting back home I installed everything back perfectly, then bled the brake system with a clear tube and a cup of brake fluid to make sure no air was in the lines. After all that I still had to pump the brake pedal at least six or seven times to build pressure. This goes for when the motor was running and off. Finally I got a vacuum bleeder to just try another bleeding method, same issue. Replaced the Master Cylinder, again same issue. Everyone tells me why it cant be the brake booster which makes sense, the pedal is never hard, only firm after several pumps then almost fades away.

As a last test I vice-gripped every brake line the block off the calipers. Perfectly firm pressure from the pedal now. One by one I took the grips off to see if one caliper was leaking even though I wasn't loosing any fluid. After taking them all off, the pressure was firm until I removed the grip of the front left caliper. Something is wrong here but I can't imagine what. I lose pressure but I don;t loose any fluid. How can that be?

Tomorrow I'm going to pull it off an see if the piston moves out when the pedal is pressed. Possibly even swap calipers for a second, not mounting them of course cause that's impossible, but at least switch them so see if the problem follow the caliper.

In the meantime any input or suggestions would be a great help, fresh rims and I can even drive it, WTF!!!

You bled the brakes correctly, right?

1. open bleed bolt
2. push down and hold pedal
3. close bleed bolt
4. let pedal back up
5. repeat until done bleeding


And did you do them in the correct sequence?

Basically yes only with two people and a clear tube submerged in fluid so should anything be sucked back into the line it would be only fresh fluid.

But that doesn't make any sense...

If you pump the pedal and the air bubbles that come out of the system go into the clear tube but do not make it all the way down the tube, and you then proceed to lift the pedal without closing the bleed bolt, that air could be sucked back in since it was still in the tube.

Also, if you were bleeding the brakes into a container, then as soon as you let fluid out of the brake system, the fluid in the container is no longer "fresh fluid" because it has been contaminated with the old fluid.


But did you use that process of opening and closing the bleed bolt or did you not?

Ok yes the fresh fluid part doesn't make sense but the tube was short enough to let the bubbles out. They were pushed out of the tube for sure but before the pedal was moved the bolt was closed so regardless they never made it back in. I did this with the tube until after every pump it was pure clean fluid. I forgot to mention the system accidentally drained itself while sitting, so there was virtually no fluid to begin with after reinstalling the calipers. I've gone thru at least one quart of fluid during the bleeding process.

The front left caliper has air trapped in it.

Any idea on how I would get that air out since it hasn't made it's way out via bleeding?

keep bleeding until it comes out. that's about all you can do.

Using an old trick that someone told me to try ended up fixing the problem. I held the caliper so that the bleeder valve was perfectly vertical so any air that was trapped could hopefully just float up and in turn, that was the fix. A pocket of air trapped and wouldn't budge.