no brakes at the pedal.. its very soft

[88bonnsse]

o.k out of no where today my wifes brakes on her 1987 delta 88 royale just got very different..

at first when i step on the pedal it feels as if there are no brakes.. but then almost right before the pedal goes all the way down the car stops kinda o.k.. but something deffinetly is wrong..

2 weeks ago i put new rear wheel cylinders and pads, front pads calipers and rotors.. and i bleed the brakes.. they were working fine..

but today they are very soft.. very very soft..


i have no clue what it could be besides the brake booster..? and if it is the brake booster how could i tell for sure..?

and i checked the fluid.. its full to the top.

[00Beast]

Sounds like a master cylinder to me. Very common failure.

If it was the booster, the pedal would get very hard to push, as the booster takes your pedal input and multiplies it.

[88bonnsse]

Sounds like a master cylinder to me. Very common failure.

If it was the booster, the pedal would get very hard to push, as the booster takes your pedal input and multiplies it.

is there any way to check if its the master cylinder..?

because i could be wrong as im still learing but i always thought the booster did all the work and the cylinder was just there to hold the fluid and drop it into seperate brake lines

[RJolly87]

The booster just helps you push the brake pedal. The master cylinder is what actually creates the hydraulic pressure to the lines, and in turn, to the wheels. You may also wish to make sure there are no busted brake lines too. Is it losing fluid? Is it low?

[ChilinMichael]

From first post:

and i checked the fluid.. its full to the top.

[88bonnsse]

From first post:

and i checked the fluid.. its full to the top.

thanks michael..



so what would make the master cylinder go bad.. ? not being air tight or something..?

[00Beast]

Lots of things, age being the main. Bad seals inside, corrosion from moisture in the fluid, etc. Definitely sounds like time to replace it and do a thorough flush of the brake system with fresh fluid.

[88bonnsse]

Lots of things, age being the main. Bad seals inside, corrosion from moisture in the fluid, etc. Definitely sounds like time to replace it and do a thorough flush of the brake system with fresh fluid.

i did a flush of the fluid about 2 weeks ago when the wheel cylinder pooped and i changed all brake parts front & rear..

fluid was good to me in color.. but there is no leaks for sure.. but i guess i will have to change the master cylinder..


my cars were good all summer now i had to do the rear brakes on my car, replace front rotors, ps pump and alternator
then my wifes car needed all brakes all around with drums and rotors plus i still need a tire and a belt tensioner bracket for my car..

its been a hell of a last 2 months.. way to much went bad at once..

[00Beast]

Just be glad it's not 20° out.

[88bonnsse]

o.k i bought a brand new master cylinder and installed it.. still no difference.. pedal goes all the way down to the floor before the car will stop.. it will stop but at last minute and kindly slowly.. so its very scary i dont want my wife driving it at all..

i bench bleed the master cylinder and after i put it on i bleed all 4 wheels..


still no difference at all.. not even a lil.. but its funny because when i bleed the barakes i made sure to bleed each side like 6 times or more untill no air came out.. did that..

still no better..


what could it be..? i have replaced everything ececpt the brake booster but 20 out of 20 people are telling me its not the booster or the brake pedal would be almost rock hard.. which its the total oppisote..


can anybody please help..?

[00Beast]

How are your rubber brake lines? If they're bad, they'll blow up like a balloon.

[88bonnsse]

How are your rubber brake lines? If they're bad, they'll blow up like a balloon.

i replaced both front rubber brake hoses about 3 months ago.. not sure but the back ones look good..

if i jack the car up and start it up then step on the brakes should i see the rubber hose swell up then..?

or how would i check for this.. i rember one of the front rubber brake lines had a bubble in it and that was the reason i replaced it because i was affraid of it poppin.. never gave me a probem with soft brakes like now tho..