I recently bought a 1993 Jeep Grand Cherokee. It wasn't drivable, the owner told me he took it to Midas and they diagnosed it with a faulty master cylinder. They quoted him $750 to replace it (even though the book time is 1 hour). I was in the market for one and the price was excellent so I scooped it. Had it towed to my house, and ordered a new master cylinder from the parts store I deal with for about $100. First mistake. Taking a Midas diagnosis seriously. After installing and bleeding the new MC, I started at the rear right, everything is fine. Didn't notice the left rear brake drum pissing all over the floor. Wheel cylinder. Master was probably fine to begin with. Rookie mistake. Bought 2 new wheel cylinders for about $10 a piece. Bought new shoes for $50. New hold down hardware and return springs for $6 and a used set of drums cheap cheap cause mine were pretty bad. Had to break rear brake lines in order to change wheel cylinder, all seized up. I think the previous guy had been launching boats or something, no structural damage but really rusty back there. So then, I go to bleed the brakes and keep getting foam coming out of the bleeders. Weird, so I double check all my work. Looks good and tight, so I try bleeding some more. Looks less foamy so I decided to take it for a ride anyway. Start it up and thick white smoke billowing from behind me. Smells like burning brake fluid. Take the master cylinder back off, my booster is flooded with brake fluid, and the vacuum hose has sucked a bunch of brake fluid into the engine. So now I've got to sort things out at the parts store regarding this faulty master cylinder. Need a new brake booster too, as I've been told the diaphrams inside it are likely damaged and not to take chances. I've also been advised that the motor should be fine internally, although its not the best for it.

I have a question you guys though. I've got a brand new exhaust system in it, and the tailpipe is dripping clear brake fluid when running. Is my catalytic converter pooched? Cause I have to take it to aircare after I get this all resolved. Does the brake fluid kill the media inside? Is this something where I can just take it for a long drive and use seafoam or something to clear it out? Or am I buying a new cat?

Thanks

 

I'd just let it run till it quits smoking. The brake fluid shouldn't hurt the platinum inside. I would be more concerned about it fouling the o2 sensor. If you haven't checked the cat yet give it a good rap and if it sounds like gravel inside it's pretty much toast anyways.
The other option is to register it outside of the lower mainland and then you won't have to deal with the goverment cash grab...I mean aircare.
Hope you get the issue with the brakes worked out. See if you can get a can of PB Blaster at Lordco or Canadian Tire, spray it on a couple of times and let it soak in well. It will usually get rid of the rust for you.

 

Thanks for the tips.. I've already got the brakes all taken care of.. I just stripped them down to the backing plate, brushed thoroughly with degreaser, sprayed with brakekleen and wire brushed by hand... good enough I suppose. I ran it for about half an hour today and its just not letting up. My neighbors are getting pissed off so I shut it down.. I'm happy to hear the cat should be alright because the whole exhaust system is brand new, it was one of the main selling points when I bought it. So I guess now I just have to see what I can get out of the parts store. It will be pretty interesting to see what they'll be accountable for. I installed their defective part, and it has written off other parts. Personally I think they should eat it and give me replacements for all damaged parts but we'll see.. As for clearing out my exhaust, I have no idea. It doesnt seem to even slow down the smoking. There must be a lot of it in there. I tried pouring some seafoam down the throttle body as well, didn't seem to help. Once it got real hot, it looked like there was a bit of smoke coming from the cat. If an o2 sensor is pooched on a vehicle this old would it throw an engine light?

 

If the sensor goes it will set the check engine light off. Seafoam down the TB doesn't do to much but if you feed it in through the vacuum line off the brakes (you know which one :) ) and then shut it down for a couple of minutes you'll get a bunch of smoke out of it.
You can always fire it up after dark so the neighbours don't see it. If it doesn't stop then I'd get a new one, just bought one for the g/f's 98 for 110.00

 

After receiving some good advice from a few people I decided to just replace the master cylinder and not worry about the rest. I flushed the brake booster with clean water several times and tipped it back and forth till I got just about all the water back out. I installed the new master and bled it as well as the brakes themselves. Didn't have any problems. I took it out for a good rip and I think all the brake fluid in the intake manifold and exhaust system has finally burned itself clean again. I've got no smoke coming out, no brake fluid dripping, and it runs like a champ. I have no check engine light up either, so I'm assuming all the emissions stuff is working fine? Anyways thanks a lot for your help 04WJ, but I've got another question for you or anyone else.

I thought the ABS light that was on when I got my Jeep would go out once all the brake issues were sorted out. I performed a hard reset after the work was all done, and I still have the ABS light. I took it up to speed and mashed the brakes to see if the ABS was working and it seems to be fine as the wheels did not lock up. I wonder if it could be the wheel speed sensors at the back because it was a nasty mess back there. But i guess it could be anything, so I would like to know if it is possible for me to check ABS codes myself, or does it have to be done at the dealer with one of those DRBII scanners or whatever they are. If it is possible to check the codes yourself, where can I find a listing of the codes and what they mean? Thanks!

 

Could be dirt or grease on one of the sensors, a broken wire, everything in the back just needs a good cleaning. Since you just replaced the booster and master you may still have a bit of air in the system also.
If you can find a good OBD II with the ABS function you might be able to run a diagnostic on it. Yours has OBD I and things were not very standardized for codes so it may not be possible. If you can't get it to go out you may have to take it to the dealer/ mechanic.