Brakes gone, need possibile diagnosis..., No brakes, but plenty of fluid. Options

[Delta_Phoenix]

Yeah, if you check the tranny forum... you'll know my clutch is gone too. The night before, I was stopping for a deer when my brake pedal went to the floor. Lucky me.

Master and slave cylinders are both full. I still have some stopping power if I push the pedal all the way down. I haven't had any symptoms of failing brakes, they've been fine for awhile now. Just all of a sudden they're gone. Shoes replaced around 8 mos. ago, and front pads are still in great condition.

Edit: Sorry for the noobish question, but brake assemblies aren't my strong point

This post has been edited by Delta_Phoenix: Oct 23, 2006 - 9:57 PM

[94celicadude]

if you are CERTAIN that your brake system has NO air in it, then you need to possible replace your master brake cylinder, $200 by the way i just did mine. After that if you problem continues, then you need new wheel bearings, i had the same prob after the new mbc and replaced the wheel bearings and now its fixed. Whats happening is that after a slight turn, the free play in the bearings allow the rotor to move more than normal, and it pushes the pistons back inot the caliper, so the next time you need to brake you need just about i full pedal travel to push them back out and begin clamping on the rotor again. Good luck

P.S. Make sure to bleed the whole brake system if u replace the mbc and also the MASTER BRAKE CYLING itself needs to be bled, which i found out the hard way.

[Coomer]

Your braking system doesn't have a slave cylinder. Are you sure you're checking the right master cylinder reservoir (the one closer to the middle of the car?)

[jcbass7]

if it comes to it i have an st parts car, i can helo you out with any brake parts from it such as the master cylinder, if that is the problem

[Delta_Phoenix]

Your braking system doesn't have a slave cylinder. Are you sure you're checking the right master cylinder reservoir (the one closer to the middle of the car?)

Yes, it's full. I'm just freaked. Threw slave cylinder in there because I am a brake noob =)

I'm going to do a complete bleed, drum and shoe replacement this weekend. Hopefully that will fix it...

[Hanyo]

your master cyclinder is the culprit.

look at where the master cyclinder connects to the brake booster. see if there is any leaks or rust there?... If there is any leaks there then there is a sign of a master cyclinder leak. you should get that fix asap.

( master cyclinder: that metal thing with the hoses and reservor is connected to)
( brake booster: this is that big black thing that is attacked to the firewall)

[Yellow94GT]

Yeah, if you check the tranny forum... you'll know my clutch is gone too. The night before, I was stopping for a deer when my brake pedal went to the floor. Lucky me.

Master and slave cylinders are both full. I still have some stopping power if I push the pedal all the way down. I haven't had any symptoms of failing brakes, they've been fine for awhile now. Just all of a sudden they're gone. Shoes replaced around 8 mos. ago, and front pads are still in great condition.

Edit: Sorry for the noobish question, but brake assemblies aren't my strong point

Often the master cylinder is thought to be the cause of brake pedal being depressed "all the way down".
According to most of the sources I've seen this is not typical. Common sources are frozen calipers (on the front of an ST) or wheel cylinder (on the rear of an ST).

The tolerances with the break system are very close. If there is not complete functioning with some of the calipers, wheel cylinder and/or shoes it will seem as if the parts visually appear to be fine and it "must be" another compenent.

94celicadude makes this point with regard to wheel bearings. Often one part with a greater amount of tolerance will allow the pedal will go all the way down.

It's very likely that there is:
1. air in the system
2. the (front) calipers are frozen
3. the (rear) wheel cylinder are leaking.
4. the (front) rotors or (rear) drums have uneven wear not allowing for the proper tolerances to be within adjustment due the the worn rotor or drum.
5. Some other adjustement contributing to tolerances.
6. Other worn or parts not within specifications.


If you don't have a manual you can get an online copy to download.
Online brake system download

Complete online '94 manual

I don't want to offend you if you have the knowledge, ability or experience but, if your not really sure you can follow the manual as it is written get someone to help or check your work.

Best of luck,

Yellow94 GT