My brakes just failed while taking my kids to school.

[ShadowsPapa]

If that bottom nut is missing, when you press on the brakes the force of the rod pressing into the back of the master cylinder *could* make the master cylinder deflect upwards, thereby allowing less pressure to be applied to the fluid. It wouldn't take much movement at all to make a big difference in braking strength.

IMO, about the only way for it to deflect enough would be to bust the top mounting ear. Even moving out 1/4" on the very bottom means only 1/8" out in the middle because it would be still mostly attached at the top. 1/8" is not a lot of movement - should still have brakes.

I'd look very very carefully at the master cylinder mounting flange - that sort of movement isn't great for aluminum or zinc alloys. CRACK.

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[Edub]

IMO, about the only way for it to deflect enough would be to bust the top mounting ear. Even moving out 1/4" on the very bottom means only 1/8" out in the middle because it would be still mostly attached at the top. 1/8" is not a lot of movement - should still have brakes.

I'd look very very carefully at the master cylinder mounting flange - that sort of movement isn't great for aluminum or zinc alloys. CRACK.

I still had brakes, but diminished.

Ill definitely inspect for cracks. but I can say that now its stopping just fine.

 

[chasebank]

I swear posting or emailing a question sparks some sort of mental search function that isn't available until after clicking "submit"/"Send". Moments after sending it out there of course we start realizing what the solution may be...

I hope replacing the nut solves the issue.

In the tech industry, we call that "rubber duck development". Happens so often, people figured they could skip the whole posting online step. Just keep a rubber duck on your desk and explain the problem to it. Sure enough, the solution (or more often than not, the actual problem) practically jumps out at you. Works like a charm!

Glad OP got the brakes fixed. But if it happens again... you know what to do!

 

[Edub]

In the tech industry, we call that "rubber duck development". Happens so often, people figured they could skip the whole posting online step. Just keep a rubber duck on your desk and explain the problem to it. Sure enough, the solution (or more often than not, the actual problem) practically jumps out at you. Works like a charm!

Glad OP got the brakes fixed. But if it happens again... you know what to do!

IM BUYING A RUBBER DUCK. do they sell them at Quadratec?

 

[Rockabillyroy]

In the tech industry, we call that "rubber duck development". Happens so often, people figured they could skip the whole posting online step. Just keep a rubber duck on your desk and explain the problem to it. Sure enough, the solution (or more often than not, the actual problem) practically jumps out at you. Works like a charm!

Glad OP got the brakes fixed. But if it happens again... you know what to do!

But now we all know this story and have it stored in the back of our minds. Plenty of times when someone else's fubar has helped me out. Hahaha.

The rubber duck on the other hand, takes all of the secrets to its grave! Son of a......

 

[Chance_P]

His breaks broke. Lol


Seriously, glad no one was hurt and it was an easy fix

 

[Master_Cylinder]

I’m glad nobody was hurt! If it ends up being my fault, I’ll take full responsibility! ?

 

[Coldtoes]

In the tech industry, we call that "rubber duck development". Happens so often, people figured they could skip the whole posting online step. Just keep a rubber duck on your desk and explain the problem to it. Sure enough, the solution (or more often than not, the actual problem) practically jumps out at you. Works like a charm!

Glad OP got the brakes fixed. But if it happens again... you know what to do!

Thats hilarious and awesome. Thanks for that… now if only I’d get ducked…. ?

 

[Jteakus]

You probably lost the seal to your booster. There is an o-ring that holds in the vacuum between mc and booster. it can be a pain sometimes when installing a new master. That would explain loss of assist and no abs light. Loss of brakes can really get your attention! Glad replacing the nut got the seal back and the o-ring didn't get distortated.

 

[Edub]

I’m glad nobody was hurt! If it ends up being my fault, I’ll take full responsibility! ?

you just need to stay planted, end of story.

 

[Joe_G]

That was it, before heading out I put a bolt back on and bingo, I have brakes again. crazy/scary how one tiny bolt could make such a difference.

Great ending to this story! And yes that's one important bolt isn't it....wow.

Funny I was just talking to a colleague at work, I unloaded some problems on him yesterday and today the solution was much clearer..helped me organize my mind. Just like your posting did!

Nice color by the way!

 

[DaveL]

Putdown your pitchforks, this very well be because of something I did but I can't figure out what.

Yesterday evening I had to uninstall my ARB compressor that I have mounted in the wheel well. to access it, I had to remove my falcon shock as the reservoir butts up against the compressor almost. to remove the shock, I lifted the driver side of the truck up to allow it to droop. the entire operation was pretty seamless, and I was don't in about 30 min. is there a chance I pulled the break line? I've done plenty of off-roading and have stuffed the wheels more than once in full flex, could this be any different?

I'm running the Falcon 3.5 premium kit that I swear came with extended break lines.

my breaks felt fine until I got to the stop sign at the end of the street, the first half of the press felt normal, but as I pressed harder, the brake felt as if to push back and the truck stopped slowing down. I had to pump the pedal then put all my weight on it in order to stop.

there is no puddle in my driveway and the first thing I did was check the brake fluid level and the reservoir is full.

any advice?

Had a Jetta with no brakes first thing in the morning. Hard pedal. It was a vacuum leak within the master cylinder. Dealer never figured it out. New master cylinder fixed it.
Hope this helps.

edit: just saw the post above. And your description of the bolt...well done.

 

[Edub]

Had a Jetta with no brakes first thing in the morning. Hard pedal. It was a vacuum leak within the master cylinder. Dealer never figured it out. New master cylinder fixed it.
Hope this helps.

edit: just saw the post above. And your description of the bolt...well done.

thanks, I wish all of life's problems were so easy to fix lol.

 

[DaveL]

I'm glad noone was hurt!

My no brakes was serious. I would take it to the dealer and vacuum was restored. Dealer said, " No problem..." (Does that make it a VW thing? ;-)

 

[Edub]

I'm glad noone was hurt!

My no brakes was serious. I would take it to the dealer and vacuum was restored. Dealer said, " No problem..." (Does that make it a VW thing? ;-)

If it is a VW thing, then I "wouldn't understand"... which indeed closes the loop and confirms that it is a VW thing.

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