240 SX brakes locking up

[owt]

I need some help people. I have a 240sx that at first had a spongy brake pedal so I changed the master cylinder, now I got a hard brake pedal and all 4 wheels lock down, thought I might have gotten a bad cylinder so I got replacement, after driving a few miles it does the same thing, all 4 wheels have brakes applied, hard pedal. Have to brake the lines at the master to keep driving. Took the master cyd and brake booster off another car, same thing, brakes locked, hard pedal. Just can't believe I got 4 wheel calipers locking down.
Any help would be appreciated.

[cotbu]

Are these stock brakes or upgrades? I assuming You've bled the brakes correctly, but still have a problem.

Take off the master cylinder adjust the 7mm nut on the booster, turn it clockwise all the way. Then adjust you're brake pedal free play. You may have to turn the rod on the booster counter clockwise to get it correctly adjusted if you find you have no brakes or it doesn't feel right. So, take precaution because you might not have brakes after your first adjustment.

[aNskY]

get better tires

[jspeedm]

Are these stock brakes or upgrades? I assuming You've bled the brakes correctly, but still have a problem.

Take off the master cylinder adjust the 7mm nut on the booster, turn it clockwise all the way. Then adjust you're brake pedal free play. You may have to turn the rod on the booster counter clockwise to get it correctly adjusted if you find you have no brakes or it doesn't feel right. So, take precaution because you might not have brakes after your first adjustment.

listen to him.

[owt]

Thanks for the information, changed the front calipers today, havent driven it yet. Did not think the plunger should be adjusted because the master and booster came off a wrecked vehicle I have. Will check it anyway if the calipers do not remedy the problem.
They are stock brakes.
Thanks again

[Ruff Ryder 6]

just wanted to say thank you cotbu for this. fixed my brake locking problem today

[cotbu]

You're welcome.