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Re: [T3] Brakes help

On 13 Oct 2005 at 11:24, David Fox wrote:

> I need help with the braking system on my 1966 Fasty.
> I had put new rotors on it and now the brakes do not
> work like they used to. I also replaced the rear two
> brakes cylinders with German parts. The brakes work
> fine most of the time but the first time you push down
> on the pedal it goes almost to the floor then gets
> harder. I adjusted the rear brakes so they are very
> close. I have bled the entire system twice. I checked
> it and it still seams the same. Is this a sign that my
> master cylinder is bad?

This sounds like rear brakes which are not yet fully adjusted, but it could be 
air in the system. I've never used them, but I really don't trust the vacuum 
bleeding concept, because it puts the pressure differential in a direction that 
would tend to suck air into the system past the seals. The seals in the MC and 
rear wheel cylinders aren't really designed to seal against negative pressure.

Bleeding does not have to be difficult. Just get a 2 foot length of clear vinyl 
tubing that will fit snugly on your bleed valves, loop it up then down to the 
bottom of a catch bottle. Open the bleed valve and pump. Ignore what "everyone" 
says about down, close, up, open, etc. That's really just not necessary.

If you have a friend to help with the pumping while you watch, then you can see 
what's coming out and when you can stop. Don't forget to keep an eye on the 
fluid level in the reservoir.

If your system is in good shape, you can just open the bleed valve and let 
gravity do all the work. Pumping only makes it go faster. If you have a wheel 
that won't bleed unless you pump, then there's a restriction in the line 
somewhere that needs some attention anyway.

When I replace brake shoes, I adjust the shoes a bit tight, while turning the 
wheel alternately forward and backward. I keep this up until I can't turn the 
wheel  by hand anymore; this centers the shoes. Then I back off the adjustment 
only as much as necessary to eliminate excessive drag. Repeat this for all 4 

When I think I'm done, I get in the car while the rear is still jacked up, 
start the engine, and lightly apply the brakes in both forward and reverse.  
Then I go see if I can adjust the brakes any tighter. If I can adjust them a 
lot, then I do the centering thing again. Repeat until no further adjustment is 

Is there any chance that your brake calipers got switched, putting the bleed 
valves on the bottom? That will make it impossible to get the air out of them.

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

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