Hey guys, I've got an interesting problem. I've been letting my '89 Dodge Raider (3.0L) sit over the winter, and when I fired it up the other day (and it fired right up...amazing), I had no brake power. The pedal just went to the floor. So I popped the hood, and noticed that my brake fluid reservoir was bone dry. hm? So, I topped it off, and still no brakes. And when I fill up the reservoir, it stays full while I'm applying the brakes. After letting it sit another week or so, I checked it out and again, the reservoir was completely dry. For some reason, it's draining on it's own. I've traced all the brake lines and can't find a leak anywhere, but there appears to be a possible leak where the master cylinder meets the power booster. I'm wondering which part may have failed, or if both parts need replacing? Any advice or suggestions would be much appreciated.

Thanks!

Hutch

'89 Dodge Raider 3.0L
~350000 miles on her

Replace the master cylinder and hope it didn't take out the diaphragm in the booster by leaking back. It's going to the floor after filling because air is now in the system or the piston can't hold the pressure or both.

NOTE: Make sure you bench bleed the M/C BEFORE putting it on the truck. There should be instructions and the little kit to do it in with the replacement part.

I have an extra power booster if your project comes to that.

Okay, I've got a master cylinder on order, hopefully that's the issue. I'm still confused where all that brake fluid is going! Although there's signs of a leak between the m/c and the power booster, it's never obviously wet with fluid when I look at it. Is there a way to tell whether the booster is shot just by looking at it?

Thanks again.
Hutch

Once you replace the master cylinder, if the pedal is hard, then the booster is bad. You can ghetto check by cranking it up to build vacuum. Then shut it off and pull off the hose going to the booster. If you hear a WHOOSH, then the booster is likely fine. If you're not seeing the fluid coming out, it's going into the booster. You'll need to get it all aout when you replace the master cylinder.

I just pulled the master cylinder out, and disconnected the vacum hose to the booster. When I did that, I did hear a "whoosh" sound as it lost pressure, so maybe the booster is okay....I think I might pull it out anyway and look for fluid inside, since I've got time before the cylinder comes in.