Science Forums 2

[TheBigDog]

OK, here is the whole ugly story...

Back in May I was making an unplanned trip to Pennsylvania. It was late at night, and I had to get there and get back in time for work in the morning. As I was driving I noticed that my brakes got very soft. Very soft. Did I mention that the brakes got very soft? But they worked.

When I got home from work the next day I checked them out and found that I had damaged the left rear brake line and it had leaked all of the fluid from the master cylinder back. My next-door-neighbor is a Ford mechanic, and he gladly crafted a new brake line for me at work. Meanwhile I rented a car. He and I bled the brakes after he repaired the line and they were still soft, but functioning. We could not bleed them 100% properly because all of the bleeder valves were seized.

I ordered new front calipers and deprioritized doing any more work for a while. I did not order rear brake stuff because I did not want to do that work.

Then in June I was in a car accident. Now I know what you are thinking, it was because of my brakes. It was not, I would have hit that car anyway. Lets move on...

So when the truck gets back from the body shop after replacing the front bumper I finally decide to replace the front calipers. When I get them out fo the box I find that they are the wrong part, or at least the brackets that came with them are the wrong part, so I have to return them for a different brake kit. The work goes easily enough and I get to the bleeding. With the engine off the brakes appear fine at all four corners. Pressing the brake pedal it is nice and firm. Pumping makes it a bit firmer and lowers the level in the resevoir above the master cylinder by maybe an eighth of an inch; just a bit of air compressing in the lines. When you let off the level rises back up slowly as the bubbles expand again. This should be fine.

Then I turn on the engine and .... the pedal goes straight to the floor with no apparent resistance at all! Repeat procedure, same result. Frustration.

So then I call the all-knowing one (my father) and explain all of this. He thinks that either there is air in the rear brake cylinders themselves, or the master cylinder has a bad seal that cannot be felt unless the power assist is running. He suggests that I begin by replacing the rear brake cylinders (because only some kind of idiot would try and bleed the brakes from the input valve), and then if that did not work to look at the master cylinder.

So today I had the car towed to a shop to have a real mechanic work on it for me. I have been driving a rental for almost a week, this is the second time I have driven a rental related to these brakes. All in the name of saving me money by doing it myself.

Tomorrow I hope to be driving my truck again and the brakes will be like new.

Bill