brake pedal goes to the floor, 63 bird

[Zee]

63 Bird, have replaced the booster, then master, wheel cylinders, shoes, hoses, been bled manually, vacum and pressure. Hard pedal with engine off, pedal goes to the floor when you start the car, but still stops the car (sort of). Have tried blocking outlet of master, started the car, and have a full brake pedal.

[novanutcase]

Sounds like you've got air in the MC. You may want to try bench bleeding it.

John

[simplyconnected]

I agree with John. Bench bleeding requires at LEAST 20 pumps on a level bench before you bring the M/C to the car. You can do it on a car but you will waste a lot of brake fluid getting there. Surf the net and see full instructions regarding BENCH BLEEDING. BTW, did you change any brake hoses? - Dave

[Guest]

Hey Guys,
I always bleed mine with everything hooked up on the car (truck). That way it gets rid of any old fluid in the lines. I get me a clear rubber hose that will fit tight over the brake wheel cylinder bleed valve. Get me a quart jar and a wrench that will fit the bleed valve. Add enough brake fluid in jar to cover end of clear tube, slide wrench over bleed valve and push other end of hose on bleed valve. Loosen bleed valve, pump brakes several times. Check fluid in master cylinder and top off. Check clear hose to see if brake fluid has got clear. I do this several times until air is out of lines and fluid is clear. Also start from the right rear first, then left rear, right front and the left front. Works every time especially if you have no help!!!
Richard D. Hord

[simplyconnected]

Rich, if your M/C is dry (like a brand new one), Bench Bleeding is a ritual that needs to be done just to get all the air out of the M/C. Usually a plastic kit comes with a new M/C, with hoses that go from the ports (front & rear), back into the bowls. You fill about half way, covering the plastic tube ends, put the M/C in a vise, and start pumping. After about 20 strokes, the bubbles will quit. This method saves a lot of brake fluid because it recycles throuth the M/C. THEN, you bring it to the car, mount it, and do a system bleed, flushing out old fluid and line air. Bench Bleeding only needs to be performed on dry or rebuilt master cylinders. - Dave

[Guest]

Hey Dave,
My bad! I missed the new master cylinder part. That's what you get when you are burning the candle at both ends I will have to totally agree with you on that!!!
Richard D. Hord

[Zee]

MC bleeding question

Would air in the master result allow the pedal to be hard without the engine on and then go soft when you started the engine?

[simplyconnected]

Maybe, if you have power brakes. The booster may not be efficient (leak vacuum) or the check valve may not work well with the engine off. As soon as your engine creates vacuum, you're back in, Power Assist-land.

How to Bench Bleed your M/C. <--click