trouble with brake pressure, brake bleeding newb Options

[Hammy]

In the process of bleeding the brakes.

Recently replaced some brake hard lines and rubber lines in the rear. They all appear to be holding up and secure.

What I am confused about is:
After bleeding all 4 calipers twice, the pedal is still not hard until it is pumped a few times.
Is this normal? Do I just need to bleed more until i get an immediate firm pedal? Or does it mean something else?

I'm wondering if it's one of the lines I replaced in the rear, yet none are leaking.

Do I need to bleed the Proportioning valve? If so, how do I do that?

Also, when bleeding, I have the tube on the bleeders and I crack them open. How much am I supposed to crack them open? Wide open? Or slightly? When they're open pretty far, air gets sucked in from the outside of the tube. Also, sometimes I get some brake fluid dripping and not going into the tube, and sometimes a lot leaks outside the tube. Is this normal for brake bleeding? (IMG:style_emoticons/default/rolleyes.gif)
Thanks.

[Hammy]

shameless (IMG:style_emoticons/default/icon_bump.gif)

[wertygrog]

Im not an expert but I've done it and I'll try to help.

I prefer the enlist a buddy to cycle the pedal method..

As for cracking the bleeders, they only need to be opened a little bit, maybe a half turn or so, so the fluid can flow.

Short answer: keep bleeding, using both bleed valves on each caliper....make sure you read the Pelican Parts article on how to do it.

Also, check your venting clearance on your rear pads.

It's possible (from what I hear) that a leaky line can let air in but not fluid out..I'm not sure if this is true though...you could try spraying your line connections with something while cycling pedal to see if there is any bubbling or something.....

hang with it man! (IMG:style_emoticons/default/biggrin.gif)

[Hammy]

Thanks for the reply and encouragement Brent.

I had my dad pumping the brakes for hours (IMG:style_emoticons/default/biggrin.gif) I've read the PP article, so I've got that method down.
The part that had the most dramatic change was stomping the pedal until it got hard and then holding it and cracking open the bleeders until the pedal dropped to the floor. That brought the pedal resistance up a little bit, but pumping was still needed to get any good pressure.

So I still can't understand why there's no immediate hard pedal until it's pumped 3 or 4 times. Could venting distance have anything to do with it? (IMG:style_emoticons/default/confused24.gif) I know the pads are pretty far away from the disks right now, but that doesn't seem to explain the pumping for a hard pedal. (IMG:style_emoticons/default/wacko.gif) I guess more bleeding? (IMG:style_emoticons/default/smile.gif)

[John]

When I recently put my car back together (I had all the brake lines off/out), I had a similar problem to what you describe and I had just switched to a 19mm master cylinder to boot.

I kept the stock proportioning valve (which got drained when it was out of the car).

I pressure bled my brakes twice before I obtained a reasonable stiff pedal. I pressure bled them and also ran the pedal down to the floor several times while bleeding the rear brakes. (This made the biggest difference and the biggest improvement).

Each time I bled the brakes, I would run a quart through the calipers (mostly in the rears).

If I had a do-over button, I would have replaced the proportioning valve with a "T" fitting and been done with it. (I have 911 SC calipers/rotors on all 4 corners).



It is my firm belief that the stock proportioning valve (pressure limiter) somehow plays a role in the difficulty in getting a hard brake pedal after it drains of fluid. Once a firm pedal is achieved, it seems like it works fine, but until then, it is a PITA.


just my $0.02