daltron

First off, I hope I am posting in the right section. My apologies if not, haven't visited the forum in quite a while.

Onto my problem...

Today I replaced all four rotors and got new pads in front and back (05 GT). The pads we replaced had no padding left and were glazed, and the old rotors were warped and cracked.

Brake fluid looked like Guinness, so my brother and I bled the brakes as well. We did rear passenger, rear driver, front passenger, and front driver side in that order. We did nothing with the reservoir other than made sure the fill level did not go below minimum.

We bled them in the following manner:

My brother pressed the brake
I opened bleeder valve (clear tubing on valve with other end in a cup submerged in clean fluid)
When liquid looked like it had stopped coming out, I closed the bleeder valve
My brother took his foot off pedal

And we repeated the above many, many times on each wheel until A) clean fluid was coming out and B) no more bubbles. We went though give or take about 40-50 oz of DOT 4 fluid.

The pedal feel was considerably better than it was originally, but it wasn't what I expected (still soft).

I was wondering if anyone can add some insight into what might be causing it and how I can remedy the situation, thanks!

Art161

Did you check the condition of the rubber hoses? If they expand under pressure, that could cause a soft pedal.

daltron

The vehicle has about 127K miles and we did expect them and they seemed to be in good shape, but to be honest I am no expert. When we were bleeding the brakes I noticed nothing odd with the lines but I'm not sure what to loom for other than movement or bulging etc.

Art161

I'm no expert either. What you looked for is what I would have looked for.

Some cars have softer brake pedals than others, so maybe it's normal for your car. I don't know what you are comparing it to.

Also, I suppose there is the possibility of an internal leak in the master cylinder, although I don't think this is common.

zinda

You said there were bubbles at some time during this operation? That should never happen, also if your fluid is turned to a different color that's a sure sign of rusted lines! Those 2 things together point directly to bad lines! There may have been water in the system at some time, like what you would expect to see happen to a car that was parked in a flood area or heavily salted roadways, or maybe just a simple wrench slip can put a small hole in those lines. Water will get in after driving in heavy rain and pushing on the pedal, then is will float around and rust out the lines. The only other way that you will see bubbles is if the fluid level dropped below the inlet to the line in the master cylinder, since you said you were closely watching the level there leaves no other way to get air in the lines. I would clean the underside of the car with a degreaser. Then pump your pedal after it's all completely dry to see where you can find an oily or wet looking area along your brake lines. If so you will then need to determine if it is rusted from the inside or outside. If it's on the inside you will need to replace all lines to be safe, these are your brakes we are talking about.

outceltj

While u were changing the pads and rotors I would have changed the lines to the braided lines for good measure. Now when I changed the rotors, pads, and lines I thought my pedal wouldve been tighter but it still felt the same so if car brakes fine with no visible leaks it should be ok

Tygr1

Keep bleeding.

90_notch

Zinda is correct, as there should have been no air in the lines to bubble out. It is a closed system, and you do not need to bleed the brakes for simply changing the pads and rotors. I understand why you did, but if the fluid was discolored and had air in it, you may have a bad master cylinder, or bad lines. I have had a bad master cylinder before, and the pedal was spongy, and I had to keep pressing the pedal harder and harder, to keep the car from rolling at stop lights. It would stop the car, but then slowly loose pressure and the car would start rolling. Check everthing to be safe.

daltron

Thanks for insight guys. Outceltj, I was thinking about it, but cost forbid that option for now.

90, any tips to check master cylinder? If I pump brakes with engine off, they will harden, haven't tried yet with engine on.

Any tips on when to know to stop?

Art161

This is one test for a master cylinder. If it fails this test, it is bad. If it passes this test, it could still be something else in the master cylinder. At least it's a start.

1. Disconnect the brake tubes at the brake master cylinder.

2. Plug the outlet ports of the brake master cylinder.

3. Apply the brakes. If brake pedal height cannot be maintained, the brake master cylinder has an internal leak and a new brake master cylinder must be installed.