Bleeding brakes on a '74

[Flying Toaster]

Just finished installing new stainless lines in place of the split rubber ones... I refilled & flushed the system using my power bleeder & Super Blue. After 2 tries now, I am still getting a real soft pedal. I assume the master cylinder is air bound? Any suggestions on bleeding the air? This is usually a 20 minute job on my VW, not sure what the issue is here.

TIA. -John

[Jim Sims]

Look for leaks under the car at fitting locations and MC.

[Flying Toaster]

That was my first thought as well. Fortunately the car is on four jack stands already & it was easy to look for leaks. None to speak of.....

[wastintime]

How soft are we talking? IMO super blue is a terrible brake fluid becuase it has such a mushy pedal feel. Is it going to the floor or does it just feel a little soft?

drive it and brake HARD, rebleed it and see how that does.

[KobaltBlau]

Sorry, that's not true. a properly bled system with super blue is hard as a rock. it ain't the brake fluid you were experiencing.

[IROC]

I agree with Andy - I've used super blue for years and the pedal is very hard. In fact, properly bled, almost any fluid will give a hard pedal (unless it's compressible, which short of silicone brake fluids, I don't think any of them are).

You obviously have some air still in the system. Sometimes tapping on the calipers with the plastic end of the screwdriver will help to work the air bubbles up to the bleed screw. Just an idea...

Mike

[Flying Toaster]

After searching, reading & trying a few ideas....

- I found the old way of pumping / holding to work a bit better than the power bleeder. I've done this method 3 times now. The pedal is getting stiffer, but, I'm not getting anymore air out of the bleeder screws. I keep seeing however, while my wife is pushing the pedal, air bubbles working their way up the clear hoses into the reservoir. Is this normal? Should I just keep doing this procedure? is there something I'm missing? TIA. -John

[RANDY P]

Something is really holding air. Did you change your pads or anything else? Could it be gaps between your pads and rotors doing this? If you haven't rebuilt the calipers they should've set the 1st pass with the bleeder? If your pads aren't set than that's a good portion of the problem. Sticking caliper perhaps?

How much pressure are you pumping your power bleeder to? Some have had better luck at 15PSI vs. the reccomended 10 or so. If your brakes are working but the feel is funny (long travel) you may want to take the car around to bang on the brakes for a bit, then rebleed. Super Blue has never given me bad feel, been using it for 2 years now...

Mine was bled 2 weeks ago after a full caliper rebuild f/r at 15 LBS on the bleeder, filled with Super, the pedal was firm but with a bit of excess travel that went away by the end of the night. 2 passes around the car. Haven't had to rebleed the pedal is as hard as a rock. Kicked the crap out of the car in the meanwhile so everything would seat.

[}{arlequin]

from reading other 'brake bleeding' posts, I can think of two things happening. Either the "pad seating/piston contact" is your problem, or you may have to bleed the master as well.