Hi Everyone, going to bleed the brakes on my 1970 and when I went to get some brake fluid the guy recommended silicon brake fluid so as to not rust the stainless steel at $10 a pint.  The regular brake fluid is only $3.50 a quart.  Any comments??????  Thanks!

Regular brake fluid is hydroscopic.  It attracts water.  The water lowers the boiling point, so the brakes fade at a lower operating temperature, when it has moisture in it.  The moisture starts to rust and decay the brake system from inside out.  That's why brake fluid starts to change color after time.  The fluid is getting dirty from rust.

Silicone brake fluid won't do that.  It does not absorb water.  But it does absorb and attract air.  This can make it difficult to bleed.  It will last for years without damage.  But it's boiling point is lower than regular brake fluid.  So it will boil and fade at a lower point that clean normal fluid, but not as bad as contaminated regular fluid.

The two products CANNOT be mixed.  You must flush the system completely when you change over the fluid types.

The silicone is excellent for cars not driven very often, and stored for long periods.  Although some people like it on a track, the fact is the regular fluid is better for racing due to the highter boiling point.   There are some synth/silicone fluids with a very high boiling point, but that's even more expensive.

I prefer to just use regular brake fluid.  But then I also flush it out every year, to keep it clean and not cause any problems, rust, low boiling point, etc.  Using silicone the flushing is not necessary, until you do other brake service.   Even in my regular drivers the fluid gets flushed every couple of years.  Every year on the Vette due to less driving.  Normal use creates heats, and that does drive some of the moisture away.  Not all but some.  I don't drive the Vette enough to accomplish that, so it's every year.

Take your choice.  It's what you want to spend, how you wish to drive, and how you wish to service the system.  There is no wrong answer here, except to fill it up and then do nothing.

kstyer38821.5254398148

Thanks for the quick response.  That was my thought, basically but thought I would ask.  Again, appreciate the response.

I use silicone and like it.  One thing, if you have any connections that are suspect, silicone will find a way to leak.  The molecules are smaller and they will find every nook and cranny to leak.  Just something to consider.  Has a nice purple color though!!!!

Mark

Good to know about more leakage.  I think I'll stick to the regular stuff becuase that is what's in there.  Maybe next winter I'll consider switching to the silicon.  Thanks for the input  It always helps to know what products others are using.

I've used the silicon stuff for 25 years. I like it

Won't hurt the paint, and really does help with cars that do not get driven enough. It is tough to get a good pedal though - and yes, I never realized that it "finds its way out much easier" than the regular stuff...no wonder I had a hassle with tiny leaks. I just took my time, and did a gravity bleed, works perfect.

The system was all replaced too, new lines, master cylinder, calipers, etc. The cost of the silicon brake fluid not significant -

 I think everybodys comments are right on. The only other thing I will add is wether Your Car has Stainless Sleave's in the Calipers. I'm not sure how many Cars are still out there that havn't but there must still be a Few. As Rusting Pistons are a well known Corvette Nemus there has been a whole Industry just Fixing them. Had all these Cars come from the Factory with Silicone Brake Fuild this might not of happened. I also have run Purple fluid in my Car for 20+ Years and never looked back. Richard...