[1964]

i have a 1964 biscayne, recently the brakes went out on me so i had to replace or rebuild just about the whole brake system, i replaced the master cylinder, rebuilt the wheel cylinders with new rubber stops and springs, replaced with new spring kits new drums and shoes, but yet i still have a problem with the brakes, the pedal still hits the floor, after all that ive still bled the lines on all four wheels to make sure there was no air in the line, but it does brake but not as well as i had it before, the lines seem fine. so my question is what could also be wrong with the car since it wont brake?

 

[64ImpalaRagtop]

I had a similar issue with my Impala but it was a vacuum pressure loss because the spring in my radiator cap had weakened and was releasing coolant whenever the engine got hot from city driving. I don't know if the Biscaynes were mechanical brakes or vacuum assist like the Impalas were. If it's vacuum assist make sure you're not dumping coolant because that can cause your vacuum system to depressurize.

 

[1964]

by vaccum brakes what do you mean by, im still just a newbie doing backyard mechanics lol, but there all drum brakes, theres one exit out of the master cylinder um there really massive brake shoes, im pretty much guessing there mechanical. but thanks for your insight im going to go mess with that see what happens.

 

[64ImpalaRagtop]

Mechanical means that your brake pedal directly moves a cable that applies the brakes. The vacuum assist system uses the vacuum system to put additional force.

 

[77Impala]

Since you put on new drums and shoes all the way around are the shoes correctly adjusted? If not then you will have more travel on your brake pedal.

 

[capricewiz]

Since you put on new drums and shoes all the way around are the shoes correctly adjusted? If not then you will have more travel on your brake pedal.

I agree. Make sure they're adjusted enough that the drums are dragging a bit.

 

[1964]

thanks yeah i believe that i did adjust the drums, but i wasnt so generous on that part, but pretty much my brakes are mechanical, i changed some brake hoses and a brake line and it seemed to do a better job, but i am a bit worried about one drum that seemed that the cylinder wasnt expanded. anyways thanks alot for your help guys.

 

[77Impala]

An easy check is to have a helper push the pedal while you spin the wheel and see how hard it locks down. I recommend using a floor jack under the wheel you question, spin it by hand and have your helper push the pedal first gently to see if the rotation slows fast, and then firmly to see if you can move the tire with the brakes applied. If you can move the tire and the brake shoes are adjusted properly then the wheel cylinder is the problem.

Your brake system is hydraulic most likely with-out vacuum power boost assist. Vacuum power boost assist came on cars as an option for drums but was mostly for front disk brake systems. If you master cylinder is mounted directly to the firewall then no power assist. If your master cylinder is mounted to a big circular thing that is attached to the fire wall then you have vacuum assisted brakes.
Here in this pic is the power booster behind the master cylinder: http://www.impalaforums.com/garage-view-image-46.html
Hope this helps.

 

[1964]

ok i see, makes alot of sense, i was talking to this elder gentleman the other day, he also told me that possibly by rebuilding the brake pistons would help alot any ideas if it could help. thanks for the help, this saturday i will be looking at it with your advice.

 

[77Impala]

You can rebuild them, but for for around $10.00 a unit I would replace the whole wheel cylinder instead of trying to rebuild it. Most of the units today come with a lifetime warranty.

 

[1964]

well tell you the truth, yesterday i changed front struts and rear shocks, i did oil change and a tune up, i did the test you told me to do, and neither of them moved, so either my brakes are really that shitty or something else is wrong, but i have noticed that my brake fluid level has been decreasing the past week. thanks for the help you guys.

 

[77Impala]

Since the fluid is disappearing look at the firewall on the outside and inside for fluid, if you see fluid on either side of the firewall then replace the master cylinder. If you have a brake power booster and you do not find any leaks any where else replace the master cylinder.

 

[1964]

um the master cylinder is new, i just settled down and decided to replace the wheel cylinders, plus some brake hoses, my cousin is a certified mechanic he told me that the brake job is done perfect but he feels that the pedal tends to loosen up after a while, its because two wheel cylinders are broken, so now i have an other problem thats easily fixed, since i put in new hoses, i have to tighten them on the cylinder before installing it, the hose leaks cause theres too much pressure and not tighten right. hopefully that would be all of the problem, and thank you very much for all your guys help, ill put pics up later