Kidcutty

Hey guys I hit the wall(figuratively speaking) yesterday trying to bleed the brakes on my 70 cutty supreme.

I have original front disc brakes and drum brakes in the back,no leaks in the system,and they work fine,pedel is half way soft.

I tried bleeding the brakes yesterday and could not get the bleeders to bleed the fluid like they should.

So I was woundering if there is a trick to these brakes I dont know about.

This is what i did:

1.uncovered the cover on fluid resevoir,but left it on top without locking it to refill as needed.Then i started with the passenger rear wheel.I also made sure it was filled a 1/4 inch to the top.

Had a buddy pump the brakes 1 time,then a second time and hold it there with pressure,then I opened the bleeder screw and a little bit of fluid came out,closed the screw and had my buddy release the pedal slowly.
I keept doing it but the fluid did not flow fully like it should.Well
i then found that i had lossened the bleeders on 2 other screws enough to leak slightly,so i was trying to purge the rear passenger screw while these other screws where slightly open.

I then closed everything and tried again and again,each time,less and less fluid came out of the rear passenger wheel till nothing came out at all.

So what a i doing wrong or whats the proper way of doing it?Sorry havent done brakes in a long while!

70 cutlass s

When I do it I have some pump them about five times the last holding the peddal down. On older cars you have to make sure the bleeders don't have dirt or something blocking the bleeders.

rocketraider

You have to hold in a button on the proportioning valve to get the fronts to bleed properly. It can be done without doing this, but takes forever. There's a tool made for it, but a small c-clamp works just as good.

I suspect that if they haven't been flushed in a long time (like most of our cars), there's some crud built up in the cylinders or bleed screws.

It's aggravating, but try taking the whole screw out and see if you get a better stream. If it's the bleeder screw plugged up you can get replacements at the parts store. if it still doesn't flush good, it's either the cylinder or the lines.

After 40 years, I'd almost be inclined to get new brake lines for the car. Peace of mind and all.

joe_padavano

That was my first thought also. I've had the bleeder screws get plugged up with rust and assorted crud. You can replace the bleeder screws if needed, but that usually means it's also time for new wheel cylinders.

Kidcutty

Do i need to push in the button to do the rear brakes as well? or just the fronts? Godamm i really dont wanna replace anything except maybe the screws. I will give it another go and see what happens,i hate when things that are supposed to be easy dont go well

66ninetyeightls

I had the same problem when I was bleeding mine and found the bleeder screws plugged exactly as the other have described. I just took mine completly off and blew brake cleaner backwards through the screw to clean it out.

joe_padavano

Sometimes you can get away with running a wire through the hole.

rocketraider

Hate to say it bo, but maybe you better find another hobby!

Old cars have sent my soul to hell more times than I can remember...

joe_padavano

hamm36

I like to ask stupid questions: Where is this button at on the proportioning valve? Will there be one on an after market kit? Thanks.

citcapp

Your not alone the line is long...................................

svnt442

1970 is different from 1971/72.

apachemobile

Ran into the same problem. Completely replaced the front brakes, proportioning valve and master cylinder/booster pump. I'll try cleaning the rear bleed screws and hold the button on the fronts and let ya'll know how it goes.

citcapp

Did you bench bleed the master cylinder before you installed it? It's an easy thing to forget

redoldsman

Best thing you can do short of replacing all the lines and other components is take it somewhere and get the system flushed and pressure bled. I have done a lot of brakes in my life buy both of my 72 Cutlasses have been the biggest pain in the butt I have ever dealt with. I dread having to deal with this when I do my disk brake conversion.

apachemobile

Guess I just wasn't turning the bleeding screws far enough, got it bled. No problems