Posted 2019-06-16 11:36 PM (#583549) Subject: Front brakes not working
I swapped in dual reservoir master cylinder in my 57 Fireflite, I also put in all new lines and wheel cylinders. I did bench bleed the master, I've got no leaks and all the air is out of the system as far as I can tell, there's no more coming out of any of the bleeders anyway.
The stream of fluid is nice and strong coming out of the bleeders when I crack them but the front brakes aren't working and the pedal goes pretty much straight to the floor. The rear brakes seem to be working fine, I can't turn them by hand anyway. I've got the pushrod adjusted to the factory spec and the shoes are adjusted correctly, I'm kind of at a loss. The master cylinder is for a 67 B/C body with power drum brakes and they're cheap Chinese wheel cylinders. I'm thinking it's something with bleeding the dual wheel cylinder setup because it's acting like there's still air in the system. Hopefully it's something simple that I've overlooked. Here's some pictures of what I'm working with. Any help would be appreciated.
Posted 2019-06-20 10:26 AM (#583764 - in reply to #583549) Subject: Re: Front brakes not working
describe how you bled the master cylinder. Did you bleed it on the bench before installing it? The best way to do this is with short pieces of tubing bent to to flow back into the top of the reservoir and with the MC clamped in a vise. Pump it until you are sure all the air is out. I have had air trapped in the forward side of the MC even though it appeared to be bled.
Posted 2019-06-20 10:37 AM (#583765 - in reply to #583549) Subject: Re: Front brakes not working
That is exactly how I bled the master cylinder. At this point I'm thinking the master might be bad. It certainly wouldn't be the first time I've had bad parts straight out of the box. I'll try putting another one in this weekend if I have time and let you guys know if that works. It's Back to the Fifties this weekend though so I might not have time. Thanks for your input.
Posted 2019-06-20 3:41 PM (#583788 - in reply to #583549) Subject: Re: Front brakes not working
Location: So. California
I must confess that I don't know if it would make any difference swapping front to back on a drum/drum master. If the reservoirs are equally sized, I don't think it would matter, but there may be some other reason not to do it like some internal proportioning system. The best way to troubleshoot is to start eliminating the possibilities before you go changing parts around. Take a hose clamper and clamp one front hose at a time to isolate that wheel and see if it makes a difference to the pedal. Make sure the edges of the clamp are rounded so you don't damage the hose. After you clamp a line and the pedal is magically fixed, you know that the problem isn't in the master and is present in that one wheel. If you end up clamping all the hoses and it still isn't fixed, you know that the problem is either in the lines or in the master.
One thing I don't like about your system are the use of those plugs in your distribution block. I have had terrible luck with them leaking. But others have gotten away with them, so they might be OK.
Posted 2019-06-20 5:59 PM (#583805 - in reply to #583549) Subject: Re: Front brakes not working
I like the hose clamper idea, I'll try that. As for the plugs in the distribution blocks, I couldn't find any replacement blocks that would distribute the lines like I wanted. Hopefully they'll work ok for me.