Brake Bleeding, Calling all witches and warlocks! Options

[McMark]

I still haven't mastered the black art of brake bleeding. Or perhaps bleeding the brakes on 30 year old worn out cars isn't effective. In either case I can't get all the air out of my lines. I've got nice new rebuild calipers and I'd really like to put them to work. What are the tips and tricks? Here's what I've done so far.

1.) Pressure bleeding: I have a spare reservoir cap that I've drilled and put an air fitting in so that I can pressurize the reservoir and push fluid through the system. When I do this right now I get no bubbles. I did notice that one of the lines from the reservoir to the master cylinder has a bad grommet and when I pressurize it leaks from the top of the master cylinder.

2.) Partner method: I've had a partner push the brake pedal while I open and close the lines. This doesn't produce any bubbles either.

3.) Mityvac: I put the Mityvac on and I got a ton of bubbles, but I suspect they were sneaking in around the bleeder screw threads.

4.) Gravity bleeding: This has been the most optimistic method I've used. Just open the bleeder screw and the fluid flows out on its own and usually brings a small bubble or two. I suppose if I did this every day after I drove it I would eventually get them all, but I am really tired of taking all the wheels off.

So now the questions. Am I missing something? Could my master cylinder be bad? It doesn't lose pressure if I press on the pedal, which I though was the sign of a bad master cylinder. Could the leaking reservoir grommet be a problem?

[Rusty]

Mark,

I use a combination of the above methods.

1. Like most things, it's always more fun (and effective) with a partner.
2. Speedbleeder screws rock. (IMG:style_emoticons/default/rocking nana.gif)
3. Get the ass-end of the car as high in the air as you safely can.
4. While your Speedbleeders are open and your partner is pumping the pedal, try rapping on the proportioning valve with a rubber mallet.

If you've done all you can, and the pedal still feels only "okay"... take it around the block a few times or to the local In-and-Out (IMG:style_emoticons/default/burger.gif). If it's safe enough to drive, then drive it a couple of days and then repeat the bleeding process. Sometimes using the system helps dislodge little bubbles.

-Rusty (IMG:style_emoticons/default/smoke.gif)