Firstly, I live in the burbs of Ohio, & work downtown, so my morning commute is much like the beginning of the movie: Office Space. As traffic accordions is way into the downtown region... there's often one of those scenarios where you've gotta brake abruptly. In fact, it happened this morning. The cause? A wreck & people just HAVE to slow down to gawk at someone's misfortune. The point of all this?

Well, as I punched the brakes because column of sheep were screeching to a halt, I heard a significant "POP" & suddenly all brake pedal pressure was gone. I start pumping the brakes frantically, only to find that it feels like the booster just blew. All while, I approach the back of the car on in front of me!

As I'm stomping, I discover there is some brake grip way down by the floor board & I really have to lay on the pedal pressure.

I've never experienced this, & it scared the hell out of me... The assist pressure never came back, so something is clearly broken, but I'm at work & havent had time to diagnose the problem. So, brake-masters of the universe, whats wrong w/ my car?

 

I would check the vacuum hoses going to the booster first. Also look for any leaks.
Glad to hear you didnt wreck though.

 

The symptoms of a failing brake booster are a hard pedal with lots of extra effort required to stop.....and not a pedal that goes way down. That would indicate a hydraulic problem. And if it happened that suddenly, I would look for a blown brake hose at one of the calipers. If the brake fluid level didn't go down at all, and no leaks were found, suspect a popped seal inside the master cylinder.

 

From the sounds, I'd guess a hose blew...

 

If this is correct, then your brake booster did not fail.

You blew a brake line. If it was the booster, then you would have an INCREASE in pedal pressure.

 

My description is accurate... I'll look for fluid leakage at the critical points of failure when I leave for the day.

thx for input, everyone.

 

make sure you haven't lost a significant amount of brake fluid, too. that'll definitely point to a leak, and you DON'T want to drive with a leak.

 

Well, with the "pop" noise.... pedal pressure went from normal to nada... poof!

 

Yeah, thats what happened to my rabbit, i heard a pop and the pedal went to the floor. Had to pump it to get any pressure. A metal line was rusted out in the back. So yeah, thats what happened to you most likely.

Funny story though, here on the expressway, traffic was nearly stopped for 5 miles because everyone was slowing down because someones boat came off their trailer and was in the grass median, no wreck or anything, just a boat in the median, stopped traffic for 5 miles.

 

thats why we have a handbrake and this cable driven. but im glad to hear you were safe from all of this.

 

Looks like I blew a brake line, drivers side rear. There was a bunch of fluid that had run down the inside of the tire & had puddled there.

This seems like a good time to upgrade to stainless lines!

 

You're gonna get jumped for calling SS hoses an "upgrade"...many people here don't trust them for one reason or another.
Personally, I've never had one fail- neither the ones I made myself nor premade from reputable companies and when I redid my hydraulics I bought a set of SS lines from Corksport (or maybe Mazdatrix...anyway, NOT no-name eBay ones) and they're fine (so far).

Much like the efan conversion, SS lines are more of a sideways mod rather than an upgrade. I've never replaced just the lines, so reports of "better pedal feel" are not confirmable by moi.

They do look spiffy though, if you're into that sort of thing.

 

I hade the same problem today I was sitting in a drive through and the peddle just went to the floor and it was fine before and I chould not figure out what happend. so when I got home I poped the hood and saw that the master was almost empty. so I went and checked the rear breaks out and found that the drivers rear banjo bolt was loose and was spewing break fluid evary where. not a good thing to happen when you are in rush hour traffic.

 

It annoys me too, but you should be thanking them really... You COULD have been going really fast when you needed to stop..

 

Had you recently been working on this caliper?
I've never seen a banjo bolt just loosen up all by itself.

 

it has been about a month sence I had worked on it. so I dont know what happend and the worst part is I was just at an auto cross a couple day ago and now im happey that it did not happen there.

 

I sense an angry X-girlfriend...

 

you think? lol.

 

Both of my rear calipers developed leaks in them. One right after the other. Would leak the reservoir down in a day. After I replaced the driver side, THE PASSENGER SIDE DID THE SAME THING. So another caliper was purchased. Sons of bee-otches I tell you.

 

People are total morons. First, the boat probably should never have come off, and second, people shouldn't stop to watch.

 

Bleh, Ordered a set of DOT approved hoses from Mazdatrix, installed them, bled the brakes, but there just seems to be ALOT of mush & very little stopping power... Less than before I installed them.

Master Cylinder or keep rebleeding?

 

bleed them again..and I would bleed ALL the brakes..starting from the Right Rear,to left raer,then Right front and left front..Always go from the Furthest to the closest..I get someone to Pump up SEVEN times,they hold the pedal ..crack the Bleeder,the Pedal goes to the flooor..they Hold the Pedal then you close the bleeder...I do That FIVE Times Per Caliper.,,then Retop the Fluid and do it,again,again,again..I have had Good luck this way.I have Intstalled Three Five lug wheel/Brake swaps..all Good to go..One was a Real Mind bender..I had the Vacuum hose on the booster to steel line reversed,and It Took me Days to figure out(brakes were Hard but they Didn't want to make the car Screech to a Halt.)

 

+1

Good post.

 

Last time my pedal popped and lost brake pressure, my rear calipers were seized.

 

Last time my brakes popped, I owned a 89 Toyota tercel Thats 10 years ago.