[T3] Broken Brakes?

Jim Adney jadney at vwtype3.org
Wed May 10 06:03:29 PDT 2017


On 9 May 2017 at 23:08, J. Jonik wrote:

>   Even though MC seems shot, this kind of bleeding
> did enough to get fluid squirts from both front valves, dribble from 
> one rear, and nothing from the other rear....which I will check as 
> advised.
>   Brake pedal never got to even near good...but, enough to 
> do that bleeding.  Amazing that with pedal down so low, the car can 
> stop....IF I drive Very Carefully during this repair adventure.

Sound like you probably don't have any brake fluid left in the rear circuit. 
Check the reservoir, keeping in mind that it has a L and a R half with a 
divider between.

> * I have a couple thru-the-car metal brake lines in parts collection.  
> But if the existing one has a rust leak...that'll be bad news because 
> driver's seat Will Not Budge to remove it to replace a brake line or 
> repair rug or floor.   Seat is frozen in place.  Tried everything a few 
> times to move it.  No luck.  No sign of any under-car dampness to 
> indicate fluid leak...but a peek behind pedal assembly finds wetness 
> around the rubber cap on the MC push rod.

Fluid on that boot is most likely due to worn out rearmost seal in the MC, 
which is the most common failure mode by far. But it can also be due to a 
rust pinhole in the F to R brake line that sprayed fluid on that boot. Old brake 
lines are not good options for replacing that line because they will need to 
be bent to install them. This is likely to break them where they are rusty. 
Keep in mind that the commonly available new lines are for Beetles and are 
too short.

> * Re/ checking bore in Master Cylinder(s) [I have about 6]...check for
> what?  Scratches?  Pitting?  Rust? Crud? 

For one that's been in service, mostly rust, as that will rapidly wear out the 
seal as the rubber seal passes over the rough rust. Sometimes we just get a 
bit of rust right at the mouth of the bore that manages to lift the seal and let 
fluid leak out. 

But look carefully at the rubber seal that's just inside the mouth. That's what 
fails most of the time. Turn the piston around and push that seal into the 
bore. See if it still fits snugly in the bore, or is it loose, so that it no longer 
seals.



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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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