I have a 2000 cherokee. I recently just got it in a trade and had to put a trans in it. I drove it for the first time yesterday and brake problems. My pedal is firm when pumped before start up but when started sinks to the floor. Sometimes I have little stopping close to near but now none at all. There is no sign of leaking fluid at tires or lines. The fluid In the master cylinder doesn't drop either and is right at safe level. I did notice on the manifold there is four ports coming out where lines or hoses are connected to. The two ports closest to the rear of the engine have lines hooked up but other two have like a rubber caps on the ports and there are lines broken before it not connected. Could this be my problem? Also the yellow cap on my master cylinder is not tight and doesn't tighten could this be it also? I haven't bleed my brakes yet.

 

Hi and welcome to CF...I would bleed all the brakes cause it sounds like you have air in the lines...Tj

 

Bleed them for sure, make sure you dont have air in your lines. Your symptoms lead me to believe thats what you got.

 

It is normal for the pedal to sink towards the floor as you mention above upon engine start up but it should not go all the way to the floor.

 

X2 it should drop slightly, going all the way to the floor indicates a problem.

 

I am bleeding the brakes tomorrow I ran out of time today but I put brakes all the way around on it. There was nothin left on the rear shoes besides steel and a front rotor was torn to shreds. I'll let u kno tomorrow wht happens and thanks guys

 

tried bleeding them but they woulndt bleed. i think the master cylinder is shot. Answers?