Synthetic vs Regular Brake Fluid

[LuckyLuke]

Synthetic brake fluid is not hydroscopic (does not absorb water) and does not eat up the paint, but soem say it creates moisture pockets that would corrode the brake cylinders etc even quicker???

Any experince?

 

[John Loftus]

Luke,

My car had silicone fluid for many years before I bought it and I did find corrosion in the wheel cylinders that suggested water pooling. During the restoration I switched to Castrol LMA fluid. I also did an experiment with the new paint (fully cured) and the Castrol did not eat the paint. Best of both worlds.

BTW, this is one of those subjects that has many threads and opinions. The search function is a good way to review what has been said in the past.

Cheers,
John

 

[Keoke]

I do not know how quick corrosion in the cylinder will occur. But reportedly since the moisture will not mix with this fluid it sets in the cylinder and initiates the corrosion.--Fwiw--Keoke

 

[PC]

Quick note: for brake fluid, synthetic isn't synonymous with silicone.

Castrol SRF synthetic brake fluid does absorb water and is classified as DOT 4. You can mix it with any DOT 4 or DOT 3 fluid (not that you'd want to). It's known for its awesomely high wet boiling point.

Silicone fluid, DOT 5, is a different animal.

As John mentioned, there's been quite a lot of discussion on the subject around here. A little searching should lead to some great info.


PC.