Brake Problem

[Sly8795]

1046591

I have a 1990 Jeep Cherokee...i have to now push the brake pedal to the floor again to stop. 2 weeks ago i had a mechanic look at my brakes cause it was doing the same thing i had to push the pedal to the floor. he said he fixed it and it worked awesome for about a day. now 2 weeks later its worse then last time. i still have full brake fluid level i just checked it. any ideas? when i start it up in the morning and press the pedal a hissing noise comes but once it warms up it goes away unless i really push the pedal down hard. is this something to worry about? thanks for you help..[addsig]

 

[RAVEN13xxx]

1046595

I would say, either rebleed the brakes (as well as the master cylinder) or your master is bypassing internally.[addsig]

 

[far_right]

1046599

i had that problem....you need a new master cyl......at least i did...[addsig]

 

[Sly8795]

1046607

how much would a new master cylinder cost when you got it done? also i dont know much about this sort of mechanical stuff but could there be a problem with the brake booster or is that part of the master cylinder?



anyone have any other suggestions it might be as well?[addsig]

 

[dingus]

1046628

does your XJ have ABS? my '90 LTD does...[addsig]

 

[Sly8795]

1046630

no it doesnt have ABS..[addsig]

 

[MudderChuck]

1046715

The wifes 87 XJ had a brake booster hiss for years. The pedal never got any harder to push. The motor didn´t idle high (typical symptom of a vacumn leak) it always passed the smog test, the intake vacumn checked out within specs. I left it alone and figured if the pedal got harder to push, to stop, I´d replace it. It never got any worse. Have noticed a bunch of XJ´s with seeping rear wheel cylinders, the brake fluid goes down real slow (a dab in months) but the pedal tends to get spongy. Your´s sounds like a bad master cylinder though.[addsig]