Brake issue on 78 Cutlass

[Wez54914]

I've replaced MC (but not booster), calipers/rotors/pads, rear steel line from prop valve to "T", rear lines, cylinders, hardware/shoes/drums. No leaks, bled like crazy...no air in system. Basically everything but booster. (Car was sitting for years)
Good hard pedal at first...First braking push i can lock up, but second quick braking and theres no lockup..just slow braking...feels like the pedal return is slow too. I think it should feel almost as good as a new car.... Could this be the booster or another issue??

 

[pagrunt]

Is the pedal hard after that first push? Check the vacuum lines for leaks. Might be a good idea to even replace the prop valve.

 

[pontiacgp]

make sure the proportional valve is reset and the pin stays in place. I had a problem with my proportional valve that would only reset if I backed the car up and slammed the brakes on a few times. I could hear the valve click when it reset. I never knew that would reset it, I was just pissed and was willing to try anything except remarry my ex...

 

[Wez54914]

Is the pedal hard after that first push? Check the vacuum lines for leaks. Might be a good idea to even replace the prop valve.

Yes, its hard..just doesnt lick up brakes, seems like just as much force as first pump.
I think the prop valve is ok, i can hear rear cylinders moving during bleeding. Trying to avoid replacing prop valve...

 

[Wez54914]

make sure the proportional valve is reset and the pin stays in place. I had a problem with my proportional valve that would only reset if I backed the car up and slammed the brakes on a few times. I could hear the valve click when it reset. I never knew that would reset it, I was just pissed and was willing to try anything except remarry my ex...

When first bleeding brakes the brake light went out and i heard the valve click, so im hoping all is well there...
I'd rather make love to a flaming porcupine than remarry MY ex

 

[pontiacgp]

it doesn't sound like you bench bleed the master, if not you'll never get the air out and that is your problem

 

[Wez54914]

it doesn't sound like you bench bleed the master, if not you'll never get the air out and that is your problem

Nope...bench bled master too...learned that the hard way 20 years ago....there is zero air in the system...i mustve pushed a whole quart through during bleeding....

 

[pontiacgp]

if the proportional valve is set I would start over again with bleeding the whole system

 

[Wez54914]

if the proportional valve is set I would start over again with bleeding the whole system

Yep....biting the bullet and getting new booster, then bleeding yet again....we shall see....

 

[pontiacgp]

is everything in it's place in the back brakes and are they adjusted?...