Hi,

I have a 91 Ford Aerostar extended van with a 4.0 liter engine. The brakes were working fine and then the brake petal starting going clear to the floor with no brakes. I then replaced the master cylinder and bleed all the brake lines with new fluid until all the old fluid and air was out of the lines. The brake petal now goes to the floor after three pumps of the petal...very consistently. Once the brake petal rises all the way up on the third pump, the petal goes all the way to the floor again. The master cylinder is a rebuild one from Auto Zone. Not sure what the problem could be or if I got a bad master cylinder from Auto Zone. Anybody have any ideas?

Thanks,
Kyle.

 

All signs point to the master cylinder, especially if it still has the same syptoms after you've replaced it. Rebuilds are never consistent. -That's coming from a guy who worked at AutoZone. Make sure you bench bleed the m/c and bleed the brakes according to what you have....ABS, etc. Also, check for any visible leaks, brake fluid missing, fluid on wheels, fluid on the driveway. Go over the system to make sure all the fittings are tight. Lastly, gravity bleed the brakes. Let them sit overnight with the bleeders cracked and then bleed them normally in the morning. Hope these basic pointers help some!

 

Oh yeah, check to make sure the back drums are adjusted, and you have good pads, etc.

 

Hi LogicalRetard,

Thanks for the information. It was definitely all bad master cylinders. We finally got a good one on the fourth try.

Thanks,
Kyle.