[TR] TR6 Brakes Update

[Dave]

I was once told by someone with experience with silicone fluids that it will readily take up air bubbles but it will release it quite readily, too.  In fact that is the technique used in very high vacuum pumps.  Therefore the technique I use is to fill the master cylinder and wait a while (couple hours if possible) before I bleed.

 

 

Dave Massey


 

 

-----Original Message-----
From: Anthony Rhodes <spamiam at comcast.net>
To: triumphs <triumphs at autox.team.net>
Sent: Sun, Nov 19, 2017 12:52 pm
Subject: Re: [TR] TR6 Brakes Update

I use silicone in the brakes and clutch of my 4A.  I am very happy. 

But it was a devil getting a firm pedal on the brakes (and to a lesser extent on the clutch)

I had heard the silicone tends to keep air in suspension (invisible tiny air pockets).  And can simply act "mooshy" under pressure. 

Eventually I tried degassing the silicone fluid and that worked.  The simplest and cheapest technique I found was to use a large, but not TOO large syringe.  Maybe use a 60cc syringe.   If the plunger is too large you can't develop enough negative PSI with your hand strength.  And you should use a plunger that has a GOOD seal, maybe 3 sealing ridges (like piston rings) rather than 1 or 2.  Or else air will leak in as you pull hard. 

Then suck up about 1/2 to 2/3 of a syringe full of fluid.  Then put your thumb over the open end to seal it.  And pull back on the plunger ...  hard.    You will see the fluid start to bubble like soda pop. Keep pulling, essentially until all the bubbles stop forming.  

Now you will see a head of air left behind at the top of the syringe.  This load is ready to be carefully and gently placed in a small  clean cup.  Do not create more air bubbles!  Repeat this with a fresh load of silicone until you have enough to flush through your system.  Return any unused portion to the original bottle.  

-Tony

Sent from my 1837 Babbage Analytical Engine


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