In the original version:
Changed master cylinder
No matter how much I bled the brakes, still got bubbles.
Solution: bleed 'me the right way with two people:
The original reason I changed out the mc was that the pedal was
grabbing too close to the floor. Since all the pads had over half their
wear left, I figured it had to be the mc.
New mc = same problem--The pedal is not getting to braking until it's
almost all the way to the floor. Sure, it'll lock 'em up on dry
pavement, but they don't feel the way my other MBs feel/felt.
So, I'm gonna try all new pads and see if that does it. Any other
suggestions for those who have traveled this road before me?
As much as you dislike the low pedal - and I would too - give it a few
days to firm up. Changing the pads at this point will only worsen the
condition, IMHO. Too many variables spoil finding a cause - except if a
"lucky number" is hit.
That said, many years ago I once reversed the calipers left to right,
right to left which put their bleeders on their bottoms. The air would
still be in the calipers if my boss hadn't seen the mistake!
What? Wait a couple of days? That's a new one on me. Also I disagree
with the "new pads will make it worse" conclusion. New pads usually
bring the pedal up considerably and might also change the position of
the masters plunger, which can work around a problem there...
Good one. In a well designed system that would not be a possible error.
Also, I agree with the previous posters who suggest using the old
school pedal method of bleeding. Suction bleeders aren't as good.
I find it puzzling that most people here seem to think that new pads
will bring the peddle up. I don;t see how this is possible. As the
pads wear the pistons just keep moving out, with the space behind them
filled with brake fluid from the reservoir. It should still take
exactly the same peddle travel to generate the same force and movement
of the pistons.
So, it would seem to me that pads would have zero effect on how far the
peddle goes before firming up. If it worked that way, we'd all notice
the peddle going lower as the pads wear, but I sure never have seen
You're right, providing you drive a modern car. Back in the days of drum
brakes (1940s - mid 1950s) pre-automatic adjusters, cars were brought
into the shop for a "brake adjustment" which involved expanding the star
wheel adjustment to spread the two brake shoes exactly, as you say, to
compensate for the linings' wear. All history now.
Can you 'pump' the pedal up?. i.e. does the bite point raise up the
pedal (away from the floor) if you pump the pedal rapidly?. If you can
pump it up, there is air in there!.
Otherwise, as other posters have stated, the pads may 'bed in', but
that should not really affect how far you press the pedal. Only
greater pedal pressure will be the big difference.
Could it be that the master cylinder piston is stuck part way down the
cylinder, such that you only have a small amount of motion that is
actually pushing the brake cylinder.
I've seen this once before on a car that had the cylinder incorrectly
assembled, such that the piston stuck part way down the tube. The
pedal always returns to the top since it has a return spring, but
whilst bleeding the brakes, since the piston did not return all the
way, you only had a short actual master cylinder piston pushing
travel. Hence the braking effort occurred right at the end of the
travel. It was a tough one to figure out. It was fixed with a new set
of rubbers for the cylinder, and the assembly instructions for
installing them followed to the letter.
The brake bite at the same place no matter how much i pump them. i'm
ordering all new brake hoses and will see if that helps it. I've had
three different mc's on this thing and once the air was out, they all
did exactly the same thing. I'm also swapping out a suspecious wheel
cylinder. I'll post the results as they come in. Thanks all for your
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