VERY bizarre brake problem

[rccardude04]

Alright, the other day, my girlfriend's festiva's brakes started getting really spongy, to the point where they would barely stop the car. After trying to bleed the brakes with no luck and some bizarre results, We tracked down a rusty and otherwise nasty looking brake booster. (The weirdness was that if you would bleed the right front, the pedal would fall as the screw was loosened. If you did the left front, the pedal would remain firm near the bottom of its travel) After changing this and noticing no difference, we moved on to the master cylinder. Having properly bench bled the cylinder, we stuck it in the car, tightened down the lines, and tested it by pressing the pedal. Lo and behold, it worked!
Now here comes the weird part...
We began bleeding the calipers, starting with the left front. The pedal fell clear to the floor like it's supposed to. He tightened the screw, i let up, and it was soft again. I pumped, he loosened, and it was doing exactly what it had been before. Nothing really comes out of it. Every once in a while, a drop of fluid or a little hiss that may or may not be coming from the line will be seen/heard.
After this, we decided to try the right front. It bled like it should. Pedal fell to the floor as the screw was loosened.
Next, I thought to try doing the left front and left rear together (since the Front Left and Right Rear are on the same line coming from the Master Cylinder and the Right front and Left Rear are on the same line) and it would fall to the floor and squirt fluid out of the Left Rear, but not the Left Front.
ANY HELP is appreciated!!!! She would like to be driving this tomorrow and we just gave up about a half an hour ago. I'm running out of ideas...
Anybody?? Please!?
Thanks in advance,
-Eric
The car is a '92 Festiva GL with 140000 miles. Automatic. A/C. No power steering, it DOES have power brakes.

[packrat427]

It almost sounds like a collapsed line to the LF caliper if you are not getting any fluid thru it ,the inside ruptures and the line pressures against itself and pinches itself off ,not letting fluid come thru.

[rccardude04]

Alright, we played with it this morning, and I used an electric pump from my r/c planes to make sure the brakes would bleed. We hooked it up to the line coming from the MC and it pushes fluid to both the left front and right rear wheels fine. We ran it till clear fluid came out, tightened everything up, and drove it around the block. The brakes worked, but were a little spongy. We went to bleed the left front AGAIN and it shot fluid out like it should with the pedal falling to the ground. Tighten screw, pump again, NOTHING HAPPENS! It went back to exactly what it was doing.
We still can't find any leaks or pinches in the lines. Everything seems to be working. It's almost like it won't pull fluid into the MC from the reservoir to that line that feeds the LF/RR brakes (I think it's the front one on the MC). I'm thinking about trying a new reservoir.
Could that little linkage piece on the Brake Booster be too long and not allowing the piston to return to where it should be???
-Eric

[89fester]

I had some very similar problems before I was able to properly bench bled the M/C, which you said you did. Can you describe how you bench bled it, because mine was more of a PITA than any other I had ever tried to bleed. I would stick with trying to find a simple solution to a simple problem even though you've been going at it for a while.

89 L

[rccardude04]

1. Clamped it in a vice like it said to in their little instruction sheet.
2. fill with fluid with the hoses going to the reservoir.
3. use a screwdriver to push it in and out slowly waiting for bubbles to surface
4. walk out to car and install.
The lines had no bubbles in them at all. As far as I can tell, every port in the M/C was full of fluid.
Thanks,
-Eric

[89fester]

Okay, that's what I tried first and it didn't work. So I got out a manual for another car and it said something a little different. It suggested that you have to cap or block off the port you are bleeding when you let the piston retract. I used some old hardlines I had laying around, and bent them to spit back into the res. As I bled the MC, I covered the tip of the line with my finger so that the air wouldn't suck back in when I released the piston. I didn't have the lines submerged in the fluid. It finally started pumping a lot of fluid both on the bench and on the car. You can of course do this on the car if you have another person to help. It just sounds so similar to a MC that has air in it.

Good luck with it.
89 L

[gomer]

I agree that this needn't be a huge problem ,, it sounds like you have a good MC and it sounds like you've got the procedures down... BUT what I would do is to get a length of clear PVC hose and a "check valve" ... they are only about $1 at Walmart in the pet section (aquarium) ... this would make bleeding the system an easy 1 person job... I think either you have a hidden leak (air getting sucked in around the calipers piston) or you're not timing the opening/closing of the bleeder correctly (less likely) ... this "fool proof" way (meaning you can't have a human error in the timing of the closing of the bleed screw) will tell you a lot..

http://www.quad4forums.com/forums/attachment.php?attachmentid=2815&d=1147292618

[packrat427]

You won't see a pinch in the line if it is collapsed internally .
You say it shot fluid out when you opened the bleeder ?
a internally collapsed hose will either keep the fluid from pressurizing the caliper or it can collapse the other way and actually keep pressure on the caliper even after you have let off the pedal , and act like it is under pressure
I can't imagine making a mistake bleeding the system everytime on the same wheel ,thats why I don't think it is a bleeding issue .I may be wrong ,but from past experience ,with a car this old the line cracks internally and the fluid gets in between the layers of hose and pushes it shut ,and will cause many issues that you cannot see.
One last thing ,does it seem to pull one way or the other when you apply the brakes to stop ?
Good luck

[rccardude04]

I didn't drive the car when they were "working" but it seemed like it went pretty straight. I know that it's the first stage of pressurization that's not working. Once the pedal is better than 50% the way to the floor, it works fine. The RF/LR work and the car will stop if forced. Just the LF/RR don't work except when you force it to pressurize.
packrat: if the line is collapsed, wouldn't it stop any fluid from ever coming out? It pressurizes sometimes right after the bench bleed, but after you bleed one caliper it stops working entirely.
I might have to stop for a one-way valve and try that method because I could then just put it on and pump the brakes right?
-Eric

[packrat427]

No,if it was collapsed it could still have some fluid ,depending on how bad it is , The harder you press the harder it would pinch off internally.
If you only applied a small amount with little pressure , it would still fill the line and maybe work somewhat,
What do you mean a oneway valve ,do you mean installing one inline ,to the front brakes , between the M/C and the caliper ?

Evertime you break the line after it acts up you release the line pressure ,and it may work the first time .

[rccardude04]

The oneway was in response to another post as far as bleeding them. Put the oneway on the bleeder so that it can bleed but not let air back in. Brake lines are cheap enough and easy enough to change, we might just have to put them on at least the front to eliminate the possibility.
Is it possible that the MC reservoir is not letting fluid into the MC?
Or, could the linkage on the booster not be allowing it to pull fluid in because it's too long?
-Eric

[packrat427]

I don't see it being the res. not filling the M/C but I thought most M/C kits came with the little hoses to bench bleed that curved up and over into the res. I hope you find the problem , It just sounds like a internally ruptured hose to me .
Good luck ,let me know what you find in the end.

[rccardude04]

Question: If it was an internally ruptured hose, wouldn't the pedal still feed pressure and feel resistance? The pedal is just dead. It's like the MC isn't even attached after you try to bleed it.
We're going to try re-bench bleeding it here in about 20 minutes, and if that doesn't work we might go get some line. But it just doesn't seem like that's it. It just doesn't make sense with what is going on.
Thanks for all the help guys!
-Eric

[rccardude04]

So we just got a new master cylinder from Autozone because it was free. Warranties are fun. Anyway, it still doesn't work. Same thing. So that kind of leaves out the theory that it maybe was a bad MC. We're going to pull the tires off of it tomorrow and see what the heck is going on. This is really getting irritating. It just won't work. I'll also try to pick up some brake lines at some point.
-Eric

[rccardude04]

Autozone doesn't have brake hoses. I just called. AND they're ~25 bucks apiece anyway. That's another 50 bucks towards a car we payed 500 for originally. Is there a way to get all the air out of everything 100% for sure? We were pretty certain there was no air in it, but this would eliminate another potential problem if there is a trick to get ALL of it out.
Thanks again guys. I think we're getting closer.
-Eric