Brake pedal goes half-way to the floor, only the first time.
Finally driving my car again after it was laid up for 2 months.
I don't think it was like this 3 months ago.
When I first press the brake pedal, it goes half-way to the floor, but then stops the car very well. If I press the pedal again within 2 or 3 minutes, it moves very little before it's stopping the car.
If I wait 15?? minutes, it's like the first sentence in the previous paragraph.
What's the problem?
Bad master cylinder?
Doubt that it's the MC, sounds more like air in the lines.
Sign of bad MC would be if the pedal drops as you hold it at a stop light. If it does that then you probably need a new MC
otherwise I'd just bleed the brakes thoroughly (until you see new fluid coming out of the bleeders) and try it again.
I probably would not pump-bleed on an older car but try to find a pressure or vacuum bleeder instead... but if you do have to pump bleed I'd have your helper put a 2x4 scrap under the pedal so it doesn't go all the way to the floor.
good luck
nate
N8N wrote in news: snipped-for-privacy@googlegroups.com:
air in the lines would make it spongy all the time not these symptons. It is probably a master cyl. or if rear drum brakes they may be out of adj. pretty common on both. KB
I'm foggy, but I think it could be a brake opening up mechanically, more than normal, as you drive, gradually pushing fluid back into the master cylinder.
If you have drums in the rear, one or both may need adjustment. Sometimes pulling up the slack with the parking brake will act as a temporary adjustment. If a rotor is warped, it could move the caliper back and forth as you drive, gradually opening it.
micky posted for all of us...
Is this the same car you did the suspension work on? If so you may have introduced air into the system through cracks in the hose or bulging. The first step is to top off the master cylinder then bleed the brakes properly, per manufacturers instructions. If that doesn't work it is probably the master cylinder, diagnose and repair per manufacturers instructions. If it has power brakes it may be the booster but IDK your set up. I have a faulty memory on this subject.
Good point, bad wheel bearing on a wheel with disc brakes?
However, I'd think that would have shown up on pre-alignment inspection
nate
Not necessarily, brakes needing to be bled can be "pumped up" and made firm... for a while...
nate
N8N wrote in news: snipped-for-privacy@googlegroups.com:
air can never be made firm. no mater how much you pump them. KB
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