[T3] Brake Lights

[Jim Adney]

On 2 Jul 2011 at 17:59, Bryon Garvin wrote:

> It was sunny today and I just had to follow my hunch and change out the
> brake switches.  I was right.  Both switches failed.  They were Euromax and
> lasted WAY less than a year....and even less than that when you consider
> that I probably only used the car as a daily driver for 4 months of that
> time.

It's possible that regular use will keep the contacts clean. I really 
don't know. I wish I had a known good solution for this. The brands I 
happen to have on hand are Euromax and Meyle. I had hoped the Euromax 
would be good, since they actually have the Audi logo on them, molded 
into the plastic cap.

Other than the logo and the stampings on the side, both of mine look 
exactly like yours, except that mine came with thread sealing 
compound on the threads.

> So, got under the car...had new switch in hand and unscrewed the old one.
>  Quickly swapped with minimal leakage and proceeded to tighten.  At the end
> of the range that it would tighten up, I gave one more final "snugness" pull
> and the damn switch broke off at the threads and I was left staring at my MC
> with threads buried inside.  The neighborhood heard a subsequent
> curse-storm. 

Ouch! That's a real bummer. I once did the same thing on a $3 million 
particle accelerator, so I know how it feels. In that case, I could 
see that the body of the switch had been bored out so that there was 
barely 1 mm of metal under the root of the threads at the point where 
it broke. There was no reason for that, but we changed to a 1/4" npt 
after that.

> 1) beware that even parts stores know Euromax is crap and so don't buy
> those!  And if you do get these "german" switches, don't tighten them TOO
> much.  Previously, I really did reef on my switches to make them good and
> sealed.  Never had a problem...but today, I learned that was probably too
> much.  Maybe I just got lucky before and these "German" switches are fine.
>  I'm not complaining about their construction.  I just think I tightened too
> much.

It may be the construction. The center hole should be small ALL the 
way thru the small dia part of the switch.

I don't generally trust most FLAPS to know the quality of what they 
sell.

> 2) Between having this system apart last summer and then again just now, I
> have a significant amount of DOT 5 brake fluid that I've recaptured from 2
> drainings.  I want to reuse it and Jim, I know you filtered yours before.  I
> forget what you said about when you reuse fluid and when you don't. 

I always reuse it.

Mix with water, shake up, and let settle a few days, then filter, 
pouring off the top DoT-5 and leaving the water, etc, behind.

Let settle a few more days and filter again.

Any residual Dot 4 or 3 will dissolve in, and be separated with, the 
water.  

If you're not sure if you got all the water out, heat it to about 250 
F to drive the last bit of moisture out.

I use large coffee filters, a large plastic funnel, and 2 L 
laboratory flasks to do this process.

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