Air in the brake system and noise issues?

[scotterson]

So my friend and I swapped suspension, and I've come across a problem regarding the brakes. When the brake pedal is constantly pumped, pressure eventually builds up, but when normally driving and applying the brakes there is a bit of pressure, then the pedal just pushes all the way down. I have to either keep pumping the brakes or I have to push the pedal all the way down to the floor in order to stop the car. Is this a problem with air in the system?

I've also noticed that if I suddenly press the brakes, the car veers to the left quickly. There is also a horrible noise coming from the right front caliper area...it literally sounds like scraping metal (I haven't checked it out yet). Does this mean my right caliper is in need of a rebuild?

I believe this all happened because I left the right front caliper dangling by the brake line with no support, then I had my friend press the brakes for me while I was tightening the left front wheel's lugs. So in general, the left side's brakes were all assembled while the right wasn't. When the brakes were pressed so I could tighten the lugs, I noticed right away that the wheel kept turning. When we checked the right caliper, the piston the compresses was fully compressed, and it was tough to get it back in.

I'm not exactly sure how the noise could be explained though. I'm pretty sure I reassembled everything back to proper torque specs. Maybe it has to do with the caliper as well?

Careless mistakes make life hard, but any answers/suggestions would be appreciated. Thanks guys.

[einstein57]

(I haven't checked it out yet).

I don't mean to sound like a dick but maybe you should check it. Probably would have been quicker to check then to write this thread.

[IRON-E]

How about you check them and report back... ;)

[scotterson]

I''ll definitely check it out when I get the time. Just sitting in class right now stressing out about the whole issue :(

[jlevie]

A sinking brake pedal is a sign of a leak in the system, or a bad master cylinder. Check all of the lines and calipers for leaking fluid and repair as indicated. If you don't find any leaks, replace the master cylinder.

The pulling in one direction under braking indicates that the brakes on that side of the car are more effective than on the other side. In this case it sounds like there's something wrong with the right front caliper. It could be a sticking caliper, bad soft line or pinched hard line, or bad ABS pump. More investigation will be be needed to determine what's wrong.

[Cha Ching]

Just bumping what jlevie has already said.

Bleed your brakes to flush the sytem. Check for leaks at the master cylinder & at each corner. Use Ate SuperBlue so you can see the new fluid coming thru at each caliper.

Brakes pulling to 1-side is usually a sticky caliper. Very easy to rebuild, check any of the usual online parts places for a rebuild kit. That's a good first-place to start.

[scotterson]

Brakes pulling to 1-side is usually a sticky caliper. Very easy to rebuild, check any of the usual online parts places for a rebuild kit. That's a good first-place to start.

Would it be possible for air to be more present in the right caliper, causing the left to grab harder, thus making the car swerve? Or does air contaminating the brake system affect all four corners equally?

The noise problem is solved though... it was just the heatshield rubbing on the rotor. Plus there's no leaks to be found, so I'll get around to bleeding the system soon.

Thanks for all the input guys.

[jlevie]

Air in the system will tend to affect all of the brakes more or less evenly. It can result in a soft pedal, but it won't cause the sinking of the pedal you describe. That can only be the result of a leak or a bad master cylinder.

Oh yeah, if the master cylinder has leaked into the brake booster, both need to be replaced. Brake fluid will destroy the diaphragm in the boost quite rapidly.

[scotterson]

Air in the system will tend to affect all of the brakes more or less evenly. It can result in a soft pedal, but it won't cause the sinking of the pedal you describe. That can only be the result of a leak or a bad master cylinder.

Oh yeah, if the master cylinder has leaked into the brake booster, both need to be replaced. Brake fluid will destroy the diaphragm in the boost quite rapidly.

Ah ok, I'll probably have to rebuild the caliper, and replace the master cylinder. What are the signs of a bad brake booster?

Also, is there anywhere I could get the master cylinder for cheaper than $240 (i believe its oem from bavauto)? Is there a generic MC I could get at autozone or anything? Same with the booster.