mysterious brake issue. Pedal goes to the floor and is binding.

[JohnZ]

Everything is bled now. I got good, clear, bubble- free fluid out of all 6 ports using the foot method with no speed bleeders. Pedal is still going to the floor and not coming all the way up. The good news is that the fluid is flowing so there is pressure somewhere in the system.

If you have fluid flow, no air, and no leaks and the pedal goes to the floor, the master cylinder is bypassing internally.

 

[vigman]

What are the conditions of the rubber lines?

All new? Are you loosing ANY fluid?
I had a similar issue in my 73.. I did get a BUNK rebuild master ( nick in a rubber seal ).

A bleeding trick...

Time the tighting of the bleeder so your " pusher" is calling the 1/2 way down point and tighten BEFORE they hit the floor. You should see the calipers making a SMALL expansion ( squeeze ) if the system is at pressure.

What pattern are you using to bleed ( rear's first, then front?)

Vig~

 

[White75]

All new? Are you loosing ANY fluid?
I had a similar issue in my 73.. I did get a BUNK rebuild master ( nick in a rubber seal ).

A bleeding trick...

Time the tighting of the bleeder so your " pusher" is calling the 1/2 way down point and tighten BEFORE they hit the floor. You should see the calipers making a SMALL expansion ( squeeze ) if the system is at pressure.

What pattern are you using to bleed ( rear's first, then front?)

Vig~

All the lines are brand new. I checked everywhere for fluid leaks, all connectors and lines and all are dry.

My pattern for bleeding is RR,LR,RF,LF.
I'm still getting clear fluid with no bubbles so I don't think there's air in the lines.

 

[vigman]

Then time to restart

and replace the master.. and start working from there.....

 

[sofast4u]

brakes or no brakes!!!

I have a 75 L48 Automatic.
The car had a leaky caliper that was discovered when it failed inspection because the pedal had no resistance (it still stopped but only when the pedal was all the way to the floor). I replaced the calipers and lines and bled the system with a pump bleeder attached to the caliper.
No Dice.
Replaced the Master cylinder because of obvious leaks near the booster. Rebled the system.
Still nothing.
I just replaced the Brake Booster and there is a bit more resistance in the pedal and when I depress the pedal with the M/C cover off I can see it squirt so I am getting something there.
However the pedal still goes to the floor. I also noticed that the pedal is binding on something but there is nothing that looks like it is in the way. I took some measurements. When the pedal is all the way forward it is 7 inches from the back of the floorboard. When you push on the pedal, it goes down 2 inches with no resistance and then you get the resistance where I assume the pedal is actually moving fluid. Release the pedal and it only goes up 4-5 inches from the floor (5 being the point where the resistance kicks in when it is depressed). To get it to come up to the 7 inch mark, I have to pull it up manually, when I do that it feels like it is binding or catching on something but I don't know what. I see a red spring at the top of the pedal and I sprayed some white lithium grease all up in there to see if that was the culprit but nothing.
So here I am with an entire new brake system (Pads, Calipers, flex lines, Master Cylinder, Brake Booster, and about a gallon of fluid) yet the problem is still there. There are no obvious leaks anywhere and all the hardline looks fine.
Is there anything else that it could be? I do not want to drive it in fear of nothing working at all (just my luck). If there is anything that anyone can think of to fix this so I can get some brake pressure and confidence in the car I would greatly appreciate it.

Thanks,
Greg Davis
1975 L-48 Auto.
"The white money pit"

Greg
I JUST had the same exact problem with my 69. It turned out to be a cracke metal brake line in the frame at the drivers rear wheel. never had any leaks on the tire or the garage floor, it all settled in the FRAME... Go figure. I dont know, but its worth a check at the rear brake lines ...
good luck. The breaks would go to the floor, but it always stopped... never rackinly but stopped....

jeff

 

[White75]

Greg
I JUST had the same exact problem with my 69. It turned out to be a cracke metal brake line in the frame at the drivers rear wheel. never had any leaks on the tire or the garage floor, it all settled in the FRAME... Go figure. I dont know, but its worth a check at the rear brake lines ...
good luck. The breaks would go to the floor, but it always stopped... never rackinly but stopped....

jeff

Thanks. I'll look at that. If that is still not he issue, the shop I bought all the parts from says they'll look at the car for free. Now that's customer service!