Re: [T3] Defective Master Cylinder?

[Jim Adney <jadney@vwtype3.org>]

On 5 Oct 2003 at 19:18, BOB2TYPE3S@aol.com wrote:

> Aaron, did you adjust the rear brakes tight first? This needs to be done so 
> you can get a proper bleed of the rears. You might also try raising the end of 
> the car you're working on to get the air bubble up. This might help for the 
> rear, and I know it will work on the fronts as I've had several cars that needed 
> this. I hope this helps.

A defective MC is certainly a possibility. These can go bad sitting on 
someone's shelf, and there's little turnover in our parts these days, so I 
suspect there are a lot of these parts which have been sitting around for a 
long time. What brand was it? 

I agree that it is important to get the rear brakes adjusted at least somewhat 
before you try to bleed, but I've never seen the need to do any more than this. 
If you only replaced the MC, then you should find the brake feel to be the same 
as what it was, or better, when you started.

I agree that if you have the front jacked way up, there may be a bubble in the 
MC that you can't bleed out. I've never noticed this, but I suppose it's 
possible. 

I think I've done lots of brake bleeding with the front jacked up. Bubbles in 
the lines will get pushed either up or downhill since the line is small. 
Bubbles in larger chambers are another matter.

You should check under the floor mat near the pedal to make sure that the main 
line to the rear didn't break when you moved it. That wouldn't be at all 
uncommon on one of our old cars, and it would certainly explain your 
observation.  

-- 
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Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
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