car started off by needing rear brake pads,so decided to do front aswell. pedal was nice and firm before replacing all pads. all pistons went back in easily but for some reason, now has very spongy pedal and goes to the floor. removed all pads and seems that front pads arent grabbing rotors like if the pistons were stuck? removed pads and they come out fine, bled ft brakes and still nothing,master cylinder?
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2001 Volkswagen Beetle Question: brake master cylinder
Answer #1Superbob June 04, 2011, 20:01Master
From what you've written, I think it's possible you have damaged the master cylinder or the ABS system if so equipped. When pushing the pistons back into the calipers, it's important to open the bleeder valves and allow the used fluid to drain into a container rather than push it back up through the master cylinder into the reservoir. This way you avoid getting moisture and grit from the calipers into the very sensitive ABS valves and master cylinder.
Without ABS, probably your master cylinder is contaminated.
With ABS, you may have air in the ABS unit or it may also be contaminated.
If you get a new master cylinder, bleed it on the bench first to be sure there isn't air in it, then install it and bleed the lines at the ABS unit, then at the wheels. I hope that the ABS unit avoided damage.
Replyjcscorpio, June 04, 2011, 20:20Rookie
thank you so much, i have already ordered the master cylinder because that was my next (guess). i feel alot better now after your respones and completely makes sense. i just hope its not the abs like you said, guess il find out. Thank you again.