Hello. I recently became the proud owner of a '90 240 sedan, 190/k miles. The brake petal went to the floor when I bought it. I bleed all four wheels and the petal came up to about 1/2 and would stop hard, but after two days it got spongy again and went to the floor.
Observations: I disconnected the brake lines at the m.c. and plugged the holes. Petal very hard pushing only 1". Both back wheels hard to bleed, using a pressure bleeder(20psi)nothing came out of nipple full open. Only by pressing brake petal was I able to get 3oz.fluid on more than 20 strokes. Front wheels bleed on pressure alone and rapid, but the brakes are tight on the front. Can't spin them with just the rotor, must have the wheels on, and even then they are hard to turn, but that isn't evedent when you are driving. One more thing, when the petal is spongy, it is possible to get a "good break" if you stomp the petal, but if you let up the least bit and then rebrake the petal goes to the floor.
Any advise where to look next?