1964 brakes

[Jeffrey G.]

I'm finishing the brakes on my 64. Is synthetic brake fluid OK or should I use conventional?

[Leif A.]

Re: 1964 brakes

Jeffrey,
Most, if not all, DOT 3, DOT 4 and DOT 5.1 are synthetic and are safe for our Classic Corvettes. Don't confuse synthetic with silicone brake fluid, which is completely different and not compatible with the afore mentioned synthetic fluids.

[Duke W.]

Re: 1964 brakes

As stated above, ALL brake fluids are synthetic because they are "synthesized" via a complex petrochemical process, not from simple distillation of naturally occurring materials.

DOT 3 , 4 , and 5.1 are polyetherglycol based, and DOT 5 is silicone based. The former are all compatible, but they readily absorb moisture which requires periodic flushing to avoid corrosion that can lead to leaks.

DOT 5 is NOT compatible with 3, 4, and 5.1. My recommendation if you want to use 5 is to start with a totally clean system purged of every molecule of polyetherglycol, which requires disassembling all hydraulic components and flushing them along with brake pipe thoroughly with denatured alcohol and thoroughly drying. Reassemble with silicone fluid as a lubricant. Buy new brake hoses, but flush and dry them, too because the ends are swagged on using conventional brake fluid as a lubricate.

Silicone fluid can be difficult to bleed. I can entrap air more readily than conventional brake fluid, but once the system is full and free of air there is little or no need to ever flush, but maybe once every 10-20 years is a good idea.

Duke

[Ed S.]

Re: 1964 brakes

Look at it this way, All C8s, regardless of brake option, leave the factory with DOT 4 in their brake lines.

[Duke W.]

Re: 1964 brakes

DOT 5 does not work well on ABS systems, which is the reason it's not used on new cars.

Duke