Brake fluid determination

[Ray A.]

I recently acquired a 61. The master cylinder level is just slightly below full. I would like to top it off for the present untill I get the opportunity to flush the brake system. Can anyone tell me how to determine whether the fluid in the system is regular brake fluid or silicone. I would not want to mix the fluids by mistake and I do not know to tell the difference.
Thanks for any help'
Ray A.

[Harry S.]

Re: Brake fluid determination

Dot 5 can start off as purple but tends to change color rather quickly. Dot 3, to me, always looked like black mud.

What is safe, drain and flush the system (alcohol is recommended), then refill the system. I do not like DOT 5 as it changes the feel of the pedal but, I have DOT 5 in my 63 as it's saves the paint.

Good Luck

[Gary W.]

Re: Brake fluid determination

If you have a bottle of Dot 3, compare the smell to what's in the M/C. Dot 3 BF has a very distintive odor.

Gary

[Daniel S.]

Re: Brake fluid determination

Take a small amount out of the master cylinder and mix it with an equal amount of water in a container. Let it settle and if it the brake fluid and water seperate, you have Dot 5 if not you have conventional brake fluid.

[Jim T.]

Re: Brake fluid determination

My experience with using silicone brake fluid in my 1968 and 1970 Corvettes for over 20 years is that I can always see through the silicone brake fluid to the actual bottom of the brake master cylinder cavity. DOT3 brake fluid will not after years of service.

[Bruce B.]

Re: Brake fluid determination

Daniels method of mixing with water and looking for separation works well.
Also the comment about the DOT 3 looking like mud is a good indication.
I have DOT 5 in 2 of my old Corvettes for years and it works great, is very stable and is easy on the brake system components.

[Jim D.]

Re: Brake fluid determination

I do not like DOT 5 as it changes the feel of the pedal but, I have DOT 5 in my 63 as it's saves the paint.

Good Luck

Installed and bled correctly, there is no difference in the feel of the pedal.

[Bruce B.]

Re: Brake fluid determination

Jim,
I agree, no noticeable difference in my C1 or C2.
The benefits outweigh most everything else.