I replaced the master cylinder bench bled it n all the brakes too. It works great when braking but as soon as I turn left or right n step on the brakes the pedal drops all the way down n it doesn‘t brake. Please help
Who cares! Don't start or quit while you can. Smoking is horrible for you.
Either your brake system still has air in it or has a leak. You haven't told us that how you bled the brake so excuse me for repeat this: General tip for bleeding all brakes is starting at the farthest point from the Master cylinder, so this is the general bleeding pattern: rear passenger, rear driver, front passenger, front driver. Sometime I'll bleed that cycle twice, by the second time you should be completely clear of bubbles. Power bleeding or manual bleeding. Another thing is double check the replacement Master cylinder, they're different as I have heard but never ran into that situation to find out. The problem is the different in the pushrod, Shorter pushrod or longer stroke/smaller bore? I don't know! But you can adjust the pushrod right at the brake pedal: You'll find a pushrod lock nut, loosen it and turn the rod to adjust. If you're still having the old Master cylinder then just compare the length of the pushrod. If your Civic has ABS (Anti lock brake system) which I've doubted it has, then by bleeding the ABS will be needed as I've seen with other models equipped with ABS; The thing is you'll need special tools to bleed the ABS. Get some help if you find no leak. HTH
