Lost brake pressure then came back?

My brakes went out while traveling down a hill; pedal went straight to the floor with little to no resistance. Pulled the e-brake and cut to the right and slid into an intersection to stop. Noticed smoke coming from right rear wheel, looked like brake fluid had sprayed out onto brake disc/wheel. Took off wheel and inspected everything, put wheel back on and started car, no problems, brakes work fine.

Once I got home I inspected everything more fully, took off caliper and it looked okay. Nothing out of the ordinary, all lines looked fine. The brakes work fine now, I had to drive 2 and a half hours on the highway very cautiously to get home but had no problems.

Rear pads are fairly new, replaced in last year or so and have less than 30% wear. Master cylinder was replaced about 6 years ago (only 50k miles though, been in college).

Anyone know how I could totally lose brake system pressure and then have it come right back? I am going to replace the right rear caliper tonight but I would feel better if I understood what happened and if it could have involved any other components. It would make sense that the seal on the rear caliper could fail and release the fluid but how would it start working again?

Just an update, hopefully someone can help me narrow down my problem now.

I replaced both rear calipers with rebuilt ones and replaced the rubber seals and boots in the front calipers. I also installed new stainless steel brake lines.

Got everything bolted back up and tried to bleed the brakes but the pedal won’t firm up while the engine is off. I was able to get an occasional dribble from the bleed screws of a few of the calipers but for the most part I can’t seem to build pressure in the braking system and nothing will come out of the bleed screws. With the engine on the brake pedal goes straight to the floor. Also, no matter how much I pump the brakes the fluid level in the MC doesn’t change.

I removed the master cylinder and bench bled it again, no change. I remember reading that new fluid can ruin old seals in a MC, could this be my problem? Before starting my brake overhaul I flushed all the old fluid out and replaced with new. The new fluid has been sitting in the MC for a few days while I worked on this. I’m thinking either the MC or the brake booster. I don’t see how the brake booster would have just given out while the car was up on jackstands so I’m leaning towards the MC.

Anyone have a similar problem?

First off, I’m thinking that the “smoke” from your original post is from you locking a rear tire when you pulled the ebrake, and not you actually losing any fluid at that wheel. Had you lost fluid you probably would have seen residue, and I highly doubt your brakes would have been hot enough to turn the fluid into smoke if any had leaked out.

Sounds like a master cylinder problem to me, but I haven’t had that exact issue, so I can’t say for sure. Too bad your car isn’t a GS, cause I just so happen to have a virtually new OEM master cylinder I need to get rid of…

good luck!

yup master cylinder. my first 4dr did the same thing in san francisco while at a stop going down hill. seal is going bad inside. basically it stays sealed and every so often it lets go till one day it finally will not hold. replace the MC and you should be fine. thats what i did and never had that problem since.

i had the same problem in my DA along time ago. i lost brake pressure while i was at a complete stop and sometimes when trying to stop. kinda scary at first. i drove about a week or less with this problem. to fix it all i had to do was replace the master cylinder and the problem was solved.

Thanks for all the input everyone. I guess I’ll be replacing a master cylinder this weekend.

Oh, about the smoke. I should have been more clear, there was actually residue on the wheel and on the brake rotor. I took the caliper off but the seals looked good and I couldn’t see where any fluid had bypassed them but somehow it came out. When I took off the wheel to check it out I burned my fingers on the first lug nut I removed, it was blazing hot.

Before I replace the MC I think I’m going to try letting the brakes gravity bleed for a bit. I’m wondering if there could be so much air in there that the MC is just pushing it around and not able to fully bleed the system.

When you bench bleed your first replacement MC or bleed the system, did you made sure you kept the brake pedal halfway depressed? You do know while bleeding brakes, you’re not supposed to fully press the brake pedal to the floor… that can mess up your new MC’s seal and cause the MC to fail prematurely… just a thought…

Yeah I only pressed it half way or less. Fortunately I had read that on here somewhere before I started or else I probably would have pressed it all the way to the floor.

Yeah I’d say just get another MC (hope yours was still under warranty) and swap it and see how that goes. There’s always a chance with buying new or remans autoparts from your local parts store… good thing they have the limited lifetime warranty. Good luck

I’m 99% sure I bought it at Advance Auto, but that was seriously in like 2003. How does their warranty work? I know for a fact I don’t have the receipt, am I SOL or can I just take the part in there and get a new one? I have a feeling I know the answer to this but just checking, never hurts to save some money.

I had a problem with intermittent pressure loss a while back in my da, turned out to be the master cylinder.

Usually when you buy at those local parts store… they have your name in their system already. Just bring it there and have them check to see if it’s still in warranty. My MC from Kragen has limited lifetime warranty, whatever tat means…

I didn’t have my receipt for a battery I bought but my name was still in the system so they honored it…

In regard to only pressing the pedal half way while bleeding. That’s not really an issue w/ new master cylinders. It’s an issue w/ old ones. With normal use your MC doesn’t see that much movement, it’s used to only a slight movement. With aged seals making them move further than they are used to is what can cause a problem. I went ahead and went to the floor when I put in my new MC.

I have said this a million times, and it seems I’m going to have to say it a bunch more. Don’t waste your time with replacement parts from Autozone, Kragen, Pepboys… Their parts are crap. IMO the only option is OEM. It’s well worth the cost. And sometimes that extra cost isn’t even that much.

or if you’re lucky enough like me and the dealership doesn’t have a part you need, we have a parts store called Smothers and they can carry OEM manufacturer parts ie., i bought a denso alternator from them a few months ago. they also can get nissin calipers, etc. i didn’t bother to ask but i believe they might be the local parts depot for some of the dealerships when an OEM part is not available in a timely manner. they also carry stuff like tokico, clutchmasters, kn, holley, edelbrock, wix, etc.

they actually have a b18c1 in their showroom. :rockon:

Well, I let the brakes gravity bleed and then did the 2-man method and bled them several times. After all this I could get the pedal firm while the car was off but once I turned the engine on the brakes were only halfway functional. The first two inches of travel or so grabs the brakes but only slightly, it then gets more firm near the lower part of the brake travel. They work but they are pretty weak and I can’t get them to lock up at all (non-abs).

I have replaced the master cylinder since last time I posted so I know this isn’t the problem. Could it still just have a lot of air in the lines? If so, how can I get it out? Since the rear caliper bleed bolts are facing down and are located on the lower part of the caliper would it be necessary to remove the caliper and swing it up so that the bleeders are facing upward to remove all the air?

Again, thanks to everyone for all the help. Hopefully I’m on the home stretch here.

did you ever fix the problem ? cause I might have the answer

Well even if he did… mind telling us what the causes are so others will know as well. I was thinking he might need to re-bench bleed his MC.

No, the problem is still not fixed. I was out of town for a while so the car has been sitting.
I don’t think it could be the MC needing to be bled again. Earlier on I bench bled the one I had originally and had no luck. I later replaced the MC with a new one, bench bled, and still had the exact same pedal feel so I think the MC is not the culprit.
melancholyda I’d be interested to know if you have a solution.

I had the same problem on my way to vegas i was only rolling on one good break all the other ones where not working went to a buddies shop out there changed master booster and calipers still nothing turns out there is a valve on the left of the car if you are facing it called a porpotioning valve im sure i spelled it wrong . Well its connected to all 4 lines mine went bad and only 1 line was getting fluid .I changed it and everything went back to normal now when I pump the breaks and bleed them fluid runs freely you might want to check that out because I changed everything else but it was the smallest thing that had my car messed up .

Ahh I see. So if your bleeding your brakes and you don’t see any fluid coming out of the bleeder nut… then most likely it’s the proportional valve?