Pedal Not Returning Upward

[whiteblur]

I have a quick question hoping to get some insight on. Haven't ever ran into the problem before so I am a little stumped. I've got my brakes bled and with the truck off the pedal is stiff and the pedal will come back towards you. Once the truck is running the pedal will stay on the floor until you pull it back towards you. A little info on the truck. Brand new booster and master cylinder, new lines completely on the truck, new wheel cylinders on the rear, new calipers front, no leaks anywhere, new vacuum line from booster, and the master cylinder was bench bled first. I'm not sure if the booster is faulty since the pedal isn't returning while the engine is pulling vacuum. Any thoughts?

[1972hiboy]

just some thoughts, the check valve is working properly for the vacuum line? if you pull the pedal back up with the engine running and you step it again will it stay stuck to the floor again? but with the truck off you can pump the brakes and the pedal holds? That sounds like a defective booster if thats the case.

Thats assuming everything else downstream is correct. no air in lines.

[whiteblur]

I have attempted to bleed the lines once more with no luck. I am hoping to just find some air haha. But yeah if you pull it back up it will stay on the floor every time it is pressed with the truck running.

[1972hiboy]

Sounds like something going on inside the booster.

[guhfluh]

I had/have the same issue on my 67. Mine isn't as bad and will eventually return all the way, but very slowly. It's my brand new booster.

Make sure the booster is adjusted correctly and the brakes do work, grab and get a firm pedal, but it sounds like the booster. I added a return spring to my pedal, but it's not the correct fix.

[Mach428]

Your post doesn't indicate if you bought the booster and MC as a unit or separate. It sounds to me like you have the wrong rod adjutment from the MC to the booster.

Also keep in mind that there isn't much travel with PB so the pedal will not come "all the way up" like manual brakes.

[whiteblur]

I have just replaced the booster today and still the pedal is staying on the floor?????

[whiteblur]

The brakes are working but pedal is staying on the floor

[1972hiboy]

Your post doesn't indicate if you bought the booster and MC as a unit or separate. It sounds to me like you have the wrong rod adjutment from the MC to the booster.

Also keep in mind that there isn't much travel with PB so the pedal will not come "all the way up" like manual brakes.

time to explore this.there is a rod usually with a adjustable tip between the master cylinder and booster. make sure this is adjusted in a way that there is little to no slack between the two. alsomake sure the pedal is correctly attached to the booster linkage. what kind of vacuum do you have going to the booster?

[guhfluh]

The booster should come with instructions to set the output rod adjustment. It's something like .010" gap between it and the master.

[whiteblur]

Your post doesn't indicate if you bought the booster and MC as a unit or separate. It sounds to me like you have the wrong rod adjutment from the MC to the booster.

Also keep in mind that there isn't much travel with PB so the pedal will not come "all the way up" like manual brakes.

time to explore this.there is a rod usually with a adjustable tip between the master cylinder and booster. make sure this is adjusted in a way that there is little to no slack between the two. alsomake sure the pedal is correctly attached to the booster linkage. what kind of vacuum do you have going to the booster?

I re-bench bled my master cyclinder and its was good. Bled out my lines again and got to noticing something alittle off. The larger portion of the master cyclinder is going low when I do the tears and the smaller portion is going low while doing the fronts. Somehow I'm guessing I got the lines ran to the opposite part of the master cyclinder. I'm guessing that is where my problem is coming from.