'96 Jetta Brakes

[evsweb]

I have a good one for all you Jetta people out there. I have a 96 Jetta GL 4 cylinder. I have had brake problems since I bought the car, I replaced all the front and rear (drums) pads and rotors. About a week later I got in the car and the brake pedal went straight to the floor, no brakes at all, but I could pump them up and get pressure. Since the master cylinder was suspect I changed it and all was fine for about a month or two. This morning I had the same problem, only this time I could not pump any pressure into the system as before. The car was not touched all night, all of a sudden no brakes.
Has anyone had a problem like this before, or know if VW has any odd ball parts I may be missing.
I have been workng on cars for over 20 years and have never seen any problem like this????
Any help would be greatly appreciated.

[boschmann]

Did you check the wheel cylinders? One may have a leak or could be frozen. Has the fluid level changed?

[evsweb]

I changed the fluid when I bought the car, which helped, and none of the cylinders are frozen.
Also the fluid level has not gone down any, so I do not suspect a leak.
I know there is a bypass valve on the rear brakes, could that cause a problem like this?
Thanks

[redhawk14506]

It might, or you have a total luser who takes joy in disabling your brakes, hehehe. Got any evil neighbors? JK. Dont know what causes the problem, but it could be electrical. I would advise going to a mechanic if the prob persists, no brakes means no good.

[miro1118]

What about the power booster. I know that this going bad could cause the break pedal to hit the floor.

[boschmann]

Propotioning valve wouldn't cause this unless it was leaking. If you checked all the hydraulics then I agree, check the vacuum booster.

[randolphtpr]

I'm Having The Same Issue And Without Hesitating Ordered A New Master Cyl. Wouldn't A Bad Vac Booster Make Idling Bad And Wouldn't You Hear The Leak(it Would Be A Big One). One Thing I Noticed Is I Can Pump The Brakes Up A Little But In A Few Seconds It Releases The Brakes.as I Hold The Pedal Down..i'm Sure I'm On The Right Track But I Only Have Spent 10 Minutes On It So Far...any Advice Adrressing This Would Be Nice...i Don't Lose Fluid ...i'm Not Going Aqround Using The Emergency Brake So I Need To Get This Fixed