silicone brake fluid

Y'all

I'm rebuilding the master and wheel cylinders in my 56 Buick. What is involved in changing to silicone brake fluid? Thanks.

Judd

 

to the best of my knowledge you simply flush out the old with the new dot 5. i wasted alot when i changed my buick over but that's all i did. i just opened the bleeders and started pumping in the dot 5 until i had a consistent amount of the purple dot 5 flowing out.
hope this helps. doug

 

I use DOT5 silicone fluid. You must flush out the old fluid, pockets of the old glycol may remain in and form slugs of old fluid and water. I over flush and I do not reuse the the fluid that was drained through the system.
I also use a Mighty Vac to suck the fluid out the bleed screw, one drawback with the hand pump vac is that it pulls so hard and air is sucked past the threads of the bleed screw, it is hard to tell if the air is from the system or from past the threads. I have a tube of brake piston grease that I lube the bleed screw threads with and that helps seal the threads while pulling a vac. Do not use any other type of grease or neversieze it may react with brake fluid, DOT 5 is very inert, but I would not take the risk.
I have heard that silicone can cause "Fisheyes" when it gets on a surface before it gets painted.
Brian

 

I have had terrible luck with silicone fluid. If you don't change all the rubber parts (wheel cyl and master cyl cups, as well as all the rubber hoses) at the time you swap to silicone be prepared to swap all the parts after you change to silicone. All my hoses swelled internally and closed themselves off, so when you hit the brakes they wouldn't release. Also all the cups swole up and leaked. This happened on all 3 cars I swapped to silicone, what a stinking nightmare!. Since then I have swapped back to DOT #3. You have been warned.

 

I've had DOT5 in my '37 Chevy coupe for well over 10 years now and have never had a problem. I've never drained & flushed it in all that time and I've never had a leak and the master cylinder shows no rust & crap at all. When I changed over to DOT5, all wheel cylinder & master cylinder parts were replaced, as were all hoses, and all the lines were flushed & re-flushed with solvent to remove any trace of DOT3. Like anything else, you get out of it, only what effort you put into doing a job right.

 

I used that stuff years ago and had nothing but problems with it. It has a high expansion rate and when it gets heated , it expanded so much that when i touched the brakes, it would not release the pressure due to expansion. try comming down the colorado rockies and not being able to used the brakes without locking them up was a bitch. would not use it again even if they paid me. my two cents worth.