Hi there, this is my first post. How exciting. I have a 94 Cherokee that has been sitting for about 2 years. Threw a battery in it, fired right up. The problem I'm having is with the brakes.. they go to the floor with very little resistance. Eventually it comes to a stop just fine and if I stab the brakes I can feel the pressure buildup, but if I hold it, the pedal will sink bakes into the floorboard. I noticed it was low on brakes fluid so I emptied about 3/4 of a bottle into the reservoir. Fluid is still at the same level after a few trips around the block and another week of sitting. It has ABS and there is still a sticker on the booster and the master cylinder. I read the 94 have ****ty master cylinders? is this true? I was thinking it could be a leaky caliper because of the lack of fluid to begin with. I tried tightening the rear drums and that didn't make any difference either. Any advice before I have to buy a master cylinder would be great, thanks

 

Check all tires and brake lines for leaks . If none are found most likely masters bypassing and leaking into booster . Is it wet under master where it bolts to booster ?

 

I recommend a fluid flush with new fluid first. check really well for leaks and if nothing then yes... replace the master cylinder

 

It isn't currently wet but the car is never driven. There is however allot of bubbling paint and crustiness that would point to it previously being leaky. I didn't see any leaks otherwise. Does that mean the booster is bad too or can I just replace the MC?

 

Bleed 'em.
If that doesn't help you need a master cylinder.