A few weeks ago I turned the rotors and drums, changed the pads, flushed the fluid and replaced it with DOT4 synthetic, bled the brakes and the pedal was firm with the engine turned off. I thought I was going to have really good brakes once I got the car back on the road. Well that did't work out as planned. My brakes are still very bad to the point where I don't feel safe driving the car.
The other day I had to do an emergency brake and my wheels didn't even lock, yesterday same thing except that there was a short squall.
I have about 500Km on the current pads and I don't see much of a difference, when it comes to braking, between the old ones (they looked OK when I took them off) and the news ones (Raybestos - semi metallic). The pressure I have to apply on the pedal seems to vary and personally I don't see any connection to car's speed or pads warm up.
The brakes in my POS '92 Jeep Wrangler and my wife's POS '90 Toyota Celica are WAAAAAY better and I mean WAAAAYY better.
Do you think my Master Cylinder/ Booster might be bad or the transmission is still putting power to the wheels, what's your take on this?
Sorry for the long post but I want to drive my Camaro and live to tell.
Thanks.

D.

 

It will be without vacuum assist.
Did you let the MC run dry on fluid, and if so, did you bench-bleed it afterward? If not, it will still have air in it.
Two other possible causes - one or both front flex hoses have collapsed, or the rear brakes need to be adjusted up.

 

I bled the MC when it was on the car. In one of my other posts I mentioned how I did it. Basically, after the MC was empty and clean I disconnected the lines between the MC and proportioning valve so I can use them as bleeding extensions, one end connected to the MC and the other had clear plastic tubing routing the fluid back in the reservoir. My wife pumped the pedal until no air bubbles were visible, this included the 15 seconds wait between depressing the pedal.
Once I was satisfied with the MC I connected the lines back to the prop valve. I did notice that the front port (rear brakes) was leaking fluid when no line was connected to it while the rear port (front brakes) was not. I don't know if this is normal or not.
Next I bled the brakes until no air was coming out, first with DOT3 until everything was nice an clean and then DOT4 synthetic. I must have used almost 4L of fluid. I did this over a few days after work (just the wheels). When I decided it was enough there was no air in the system, the pedal was firm, the travel was short, all in all it felt like a proper brake pedal (engine off - no vacuum).
The flex hoses look fine, I was careful to break in the pads with light braking at low speeds etc etc.
The drums I think are OK, the shoes were lightly rubbing against the drum so I assumed they didn't need any adjustment.
One other thing I noticed was that the T splitter on the rear axle, is a bit "wet" and initially I though I had a leak but by brake fluid level is OK. The wetness is not big but it is located around the T.
What is hose collapsing? Too much flex in the hose? Both front hoses looked very good.
Does anyone have the thread sizes for the MC ports? They are different sizes (front - back) and I'd like to get extra MC to prop valve lines for future MC bleeding.
Thanks.
D.

 

What did the pedal feel like when you tried to lock up the brakes.

Was it firm and no brakes or did it go to the floor?

Do you have to pump to pet a pedal?

Does it have initial bite and then go away.

More details on what it is doing other than not stopping

 

The pedal was OKish, it didn't go to the floor but I had to apply a lot of foot pressure to get the car to stop. Quite honestly I can't remember if it was firm or not because it scared the s$$it out of me when the car wouldn't stop like it should. I wasn't going too fast either, I guess my speed was about 60-80 Km/h. Pumping the pedal doesn't really make a difference.
I don't think that I have initial bite and then it goes away. When I'm stopped at a traffic light the pedal doesn't go soft but the pressure I have to apply on it is quite a bit. Sometimes my leg gets tired and I have to use my left leg to keep the car from moving on a level road.
As a side note, when I use my left leg, the pedal feels really good but I guess it's just because my left leg does not have the control over the pedal like my right leg does.
For some reason, the brakes seem to be a little better now but it's hard to tell given that I drive in such a way so I don't have to stop in an split second (I keep my distance, don't drive fast when other cars are in front of me, etc).
Now I have about 800Km on the pads, when should one notice brake improvements on new pads? Is it in the first couple of hundred miles or over a thousand?

 

Sounds like a bad brake booster to me.

Check to make sure taht it is hooked up to a good vacume source.

The reason that I believe this is the stiff pedal and lack of pedal travel.

The brakes act like the wheel cylinder are not getting any line pressure.

 

How do I check to see if it is a good vacuum source?
Do I have to use a (special) vacuum gauge?
Thanks.
D.

 

There should be a hose running from the booster to the carb or intake manifold.

The hose should be one of the larger hoses.

Crank the engine, pull the hose off of the brake booster and put your finger over it to determine if ther is sufficient vacume.

If should suck to you finger like a vacume cleaner. If there is little suction take the hose off and check for obstructions and or cracks in the hose. Inspect where it connects to make sure there are no obsructions.

If all check out ok try the break without the hose in your drive way or other safe place. If the brakes are no different then you do not have a functioning vacume booster.

Replace it with a new one.