Topic: Brake Issue
in Forum: C3 Engines, Driveline and Handling
months ago. Pedal got realy soft and spongy, the brake lite came on.
Checked the brake resevoir and it was full. This lead me to believe that
the master cyclinder was bad. so replaced it with rebuilt, bench bled the
master and then bled the lines at each corner after it was installed (both
bleeders). That lasted for about 100+ miles before it did it again, this
time purchased a new master, bled everything again. Once again it lasted
for about 100 miles and has done it again. Have I missed something
here, or am I just running into junk masters when I get them from the
local parts house? Any help would be appreciated.


Moderator
It helps to use a large rubber mallet to tap on the calipers while you open the bleeders. This dislodges any air bubbles the might stick to the insides of the caliper.
Also, if the rotors have excessive run-out, then they will actually suck air into the calipers while you drive.


If you are sure there is no air in the system, drive the car around the block a couple of times, and then bleed the brakes again. If you get any air, then you probably need to check the run-out on your rotors, and have them machined if you find them out of spec.


(btw.....the forum you were looking for is 'C3 Handling components')

Joel Adams
C3VR Lifetime Member #56
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After the new master was put in the brakes were bled, and it didn't last long. The brakes were then bled again to see if I sucking air, and no air could be seen during the second bleed. However, the brakes did go back to normal for a while then the same thing happened again. During the initial bleed when the first master was replaced the right rear had a great deal of air in the line, more then was expected. But since then its been pretty much the same on all corners. I'm getting ready to put another new master into it from another supplier. It should be here in about a week. However, in the mean time checking the rotor run out is probably a good idea.
Thanks
I found that gravity bleeding worked the best for me....Got the best pedal I've ever had......Forget a Mitey-Vac...All that does is make your hands sore and tired......Just my 2 cents
reid
Brian - NCM Lifetime Member
73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System
