Hate to start a new thread...

[Sean]

My brakes are really soft. I mean, they're OK, but NOT to my liking. Having stainless steel brake lines as well has newly rebuilt calipers should give me much better brake feel than what I've got.

To start the story, a little over a week ago, I removed all four calipers. I removed the brake fluid reservoir a few days later.

I let this sit, until basically tonight. At which point I put my stainless steel brake lines on, and all my newly rebuilt calipers.

At that point, I removed the Brake Master Cylinder to attempt to bench bleed it. I set up some extra brake hardlines I had sitting around to go back into the reservoir to begin bench bleeding it. When I saw how dirty these lines were making my fluid, I just scratched the idea all together, and dumped all the nasty fluid out, and cleaned out my reservoir again. I want clean fluid! lol

So, at that point, I needed to get my car done, so I put everything back together and pressure bled the system with a BavAuto pressure bleeder set at 15 PSI.

All four corners were good, from what I could tell. No bubbles. I want thru probably half a quart or more just bleeding the system.

So, now...my pedal feels abnormally soft. I actually don't like it at all. You'd think with new brakes, calipers, and brake lines that things would be nice and stiff. Nope...

Should I remove the MC again and really bench bleed it, or does it make that big of a difference? What is teh screw on the MC for? to drain it? :?


Or, should I just bleed it some more?



As a side note: The car does hit ABS, but the pedal is still very soft. It also jerks side to side, which I'm guessing has to do with the fact that I just finished installing NUMREROUS suspension components, and the car needs an alignment.

Thanks in advance..

[nando]

installing suspension wouldn't make your car jerk side to side under hard braking.. especially since there's nothing to align except your toe setting, and that's not something that will cause your car to do wierd things (unless it's WAY off)

[Sean]

installing suspension wouldn't make your car jerk side to side under hard braking.. especially since there's nothing to align except your toe setting, and that's not something that will cause your car to do wierd things (unless it's WAY off)

Than what could cause it? I mean, the wheel jerks side to side. I thought that would be because of the alignment issue.

I did put in new strut mounts, tie rods, and control arms. So, the car DOES need an alignment. It's alittle off, but not bad.

Regarding my brakes. After today, i've realized they aren't really that bad. They've begun to feel a lot better. However, I still wish they were a bit stiffer, and not so soft. I still think it's a bit better than it was before.

[nando]

again, all they can change is toe. having a bit of toe out (which is what you will have after lowering your car) will not cause anything bad, other than maybe tire wear on the outsides.

I left my car with a bit of toe out and I love it that way. ;)

[Sean]

So, would the cause be my calipers? Or, what could it be? It's not the best thing if the car doesn't brake in a straight line... :?

[Brew]

Than what could cause it? I mean, the wheel jerks side to side. I thought that would be because of the alignment issue.

Normally if the steering wheel is jerking, you've either got an issue with your ball joints or your front tires are out of balance.

What type of brake fluid are you using? A soft pedal almost always means there is air in the lines, but DOT 5 fluid will also do it.

[UNHCLL]

22mm MC?
those are soft, no matter what.

[trent]

22mm MC?
those are soft, no matter what.

I agree. You shoulda stepped it up to a 23 or sort.

[Sean]

I still can! :)

I'm using ATE Amber fluid.

Here's an idea...I'll figure out what upgraded master cylinder to get, then rebleed the system. It'll do for now. ;)

[cthulu703]

I ran into the same problem when I bled my brakes. It turns out that I blew the seals on the MC. Piston does not travel the full distance of the cylinder during normal usage, creating a shoulder on the bore of the cylinder. When I compressed the pedal the entire way, it damaged the seals and my brakes went squishy, then failed completely. I ended up replacing it with a 25mm MC from a 735il. Not only is there better feel, it also is cheaper the the stock replacement.

[AdamF 88iS]

If the steering jerks to the side when you hit the pedal you probably have a caliper on one side that isn't functioning causing the car to not stop straight. Recheck all your work.