[customdrumfinishes]

Hello
this is a 72 chevelle with drums all the way around, please dont tell me to convert to disc i dont have the money. the pedal has always been alittle spongy but now the pedal has gone to the floor. there is barley any pedal at all. i removed the wheels and checked the brake pads and drums and adjusted the brakes. they needed very little adjustment.the brakes pads are almost new and look great. fluid is at the top and looks good, its not dark colored.
im doing troubleshooting at the moment to figure out the cause of the weak pedal/brakes. any suggestions would be great!
i figure the booster is ok since it isnt hard as a rock to press the pedal but im not a brake mechanic either. maybe there is aleak in the system or needs bleeding i not sure thats why im here! thanks

[poncho62]

If they were working..........and there is no fluid pouring out of a broken line etc, then it is the master cylinder......The internal seals are shot.

[Henry Highrise]

A spongy pedal is usually a indication of air in the system, which could mean you have a leak somewhere. Have you had to add any fluid? If so then check and see if everything, all the lines, wheel cylinders etc are dry. If everything is dry then check the back side of the master cylinder and see if its wet around the back of the piston. It could be leaking there and you not know it because you can't see it with it bolted to the booster.

[customdrumfinishes]

the pedal has always been a little spongy/bad in my opinion. i looked and see where it looks like some fluid has leaked from behind the master cylinder. the cylinder is about 2 years old so i wouldnt think it is bad but it could be! the brake cylinders are dry and there are no leaks anywhere else in the system that i see. although i did put some fluid in it about a month ago and i thought there might be a problem although it was a very small amount, about 4 tablespoons oil fluid was added.
if there is a small leak at the rear of the master should i replace the master cylinder or just tighten the mounting nuts and bleed the brakes?

[1931 steve]

Originally Posted by customdrumfinishes

about 4 tablespoons oil fluid was added.
if there is a small leak at the rear of the master should i replace the master cylinder or just tighten the mounting nuts and bleed the brakes?

I'm sure you just misspoke about "oil Fluid" or at least I hope. You did use brake fluid when you topped off the brake fluid reservoir? Please say you did....

If you have a leak at the master cylinder, yes you need to replace with new and bleed brakes.

Steve

[customdrumfinishes]

lol yes i ment brake fluid not oil! i will replace the master cylinder to make sure. there cheap and not to hard to put on. i was wondering about buying the self bleeder pump so i can bleed the brakes my self instead of having someone have to pump them. i have nver used a one man brake bleeder ive always used a person at the pedal. does the one man bleeder work good? i am going to take the car to a mechanic if i cant get the brakes back after the master cylinder removal and bleed.

[jray]

If you have any fluid at the rear of the Master Cyl by all means replace it NOW before you mash the pedal and get that stepped-on-a-grape feeling..
I would suggest the MityVac system....works really well and useful for other applications as well. If after bench-bleeding the new cylinder and the brakes, if you still have that spongy feeling, get some advice/help from a brake expert.