[getmygoat]

Hi all,

I recently replaced the rear rubber brake hose and rear brake lines. Trying to get the pedal to firm up - having a difficult time. Using a vacuum pump bleeder on the rears (doesn't seem to work on the fronts).

I've getting a ton of bubbles continuously from the rear lines as shown in the video below. I suspect this indicates one of my recently replaced lines isn't sealed? Someone commented earlier that the stainless lines can be more difficult to get sealed. I'm not getting any leaks, at least none I've detected.

https://www.youtube.com/watch?v=wu6i8zxi8jI

Thoughts?
Thanks!

[leeklm]

Good chance you are pulling air in via the threads on the bleeder screw. Remove bleeder screw and apply a couple layers of teflon plumber's tape. Put screw back in part way, try not to go too far, having to back it out, which could unravel the tape and lose your seal.

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[getmygoat]

I was wondering if the hose was leaking at the screw, but the pump holds vacuum with bleeder tight. Is bleeder open a different leak path?

[Sirrotica]

Once the 45 degree seat between the bleeder and the wheel cylinder is closed, the path through the threads is closed too. The vacuum is only drawing on the hollow bleeder which is now sealed.

[ZeGermanHam]

I'd agree that using some teflon tape on the bleeder screws is a good practice. Just makes life easier, and if it's not the cause, at least you have ruled it out.

The big question I have is regarding your technique. In the video you posted, it sounds like the pedal is being pumped up and down? Or is that something else?

Stainless lines are indeed more difficult to get a good seal, but I'd expect that you would see a leak when if you are able to build even a little line pressure.

[getmygoat]

The pumping you are hearing is my hand held vacuum pump. Sucking the fluid through the line.

The fronts won't gravity bleed either. There were gravity bleeding before I took it for a test ride. Now nothing. I tried closing the bleeders and pumping the pedal, then reattempting the gravity bleed. Nothing. What a PITA.

[T.Weber]

Might be a dumb question on my part but did you use that little tool to hold the shuttle valve in the proportioning valve centered before you started bleeding the brakes? I honestly don't know if the proportioning valve not being held centered would cause bubbles in the fluid though.

[Murf]

See if you can beg, borrow or purchase a pressure bleeder. They work much better for me. Also when I’ve had trouble with stainless lines sealing. I tightened them down, loosened them them tightened them down again. It seemed to help.


Good luck!
Murg


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[ZeGermanHam]

Was this problem ever solved?