I have a 71 cutlass I am trying to bleed brakes on. This has perplexed me for a few days and I can't really find a solution. I have new master cylinder, new wheel cylinders and brand new lines and this is where things have me stumped. This is going to be a two part question.

1. Front brakes bled amazing and appeared to work fine, then went to the back brakes again to bleed more. Then about half way to the floor it feels like the pedal hits a wall.

2. Back brakes have very low pressure after the fronts were bled. Barely anything comes out and it seems like it's just not getting enough to engage.

I put in new wheel cylinders and rechecked the lines and everything looks good to me. Maybe I am missing something obvious here but anyone have any ideas?

 

Does the '71 have a proportioning or delay valve bypass button like the '70 does?

You have to hold it in to bleed the brakes.

- Eric

 

Has a proportioning valve which I just replaced. Tried gravity bleeding and pedal bleeding but no pressure is getting to the back.

 

put the prop valve that works back in, maybe?

Why was it replaced? not pretty enough?

 

Let's back up. Is this car disc/drum or all drums?

 

Yes it is disc/drum. As for the valve, I bought the car about a year ago and drove it maybe a whole 2 miles before winter hit so I am making an assumption it didn't have working rear brakes then either. It was all but plugged when I pulled it last week and put the new in so it could be good or might not be.