C1 - Brake replacement

[Rich Webster]

Hello,

I'm new to the Corvette hobby, I have a 1960 that was leaking brake fluid from too many locations. I have completely replaced all the brake wheel cylinders, lines, blocks, and master cylinder. I have read the archives about brake fluids, DOT 3, DOT 4, and Synthetic DOT 5. But I did not see anything on Synthetic DOT 4, which Prestone list on their website. While reading the archives the group seemed split on synthetic and mineral types. The one thing that stood out was Synthetic does not eat paint, and Synthetic DOT 5 is not good for a C1, and to use DOT 4. Does anyone know if the Synthetic DOT 4 eats paint? It seems it could be a good choice for my Corvette.

[Jack H.]

Re: C1 - Brake replacement

There are many posts on this in the archieves with pro and con issues. Conventional brake fluid works well and considering these cars are typically 'weekend warrior' vehicles used only on nice warm days, the standard fluid should last a LONG time.

A number of racers prefer the silicone based fluids, BUT they're REALLY getting on their brakes, pushing cars to their performance limits AND doing a lot of maintenance between races.

Conventional brake fluid is hydroscopic meaning it 'likes' to absorb air borne moisture. Over the years, water in the brake fluid can attack and rust parts unless you do due dligence in replacing your brake fluid periodically.

The silicone based substitute doesn't have this affinity, but it is areoscopic meaning it 'likes' to absorb oxygen. This can result in air pockets in the brake lines and more than one owner has reported the sudden loss of brakes with the pedal going to the floor!

One of my Corvettes which I use as a 'driver' and have logged +55K miles on now has conventional brake fluid. My other car is a 'trailer queen' that's seen less than 500 miles of use in +12 years and it's filled with silicone synthetic. Both work well...

[Jim D.]

Re: C1 - Brake replacement

I've been running DOT 5 silicone fluid in my 60 for 25 years with no problems.

[Ken A.]

Re: C1 - Brake replacement

Jacks response pretty well hits the nail on the head regarding the two types of brake fluid. I used to run silicone in my 69 when I was autocrossing it, but I finally got tired of the soft brakes. I went back to conventional brake fluid and the brakes are much better. When I built my 72 autocross car, there was no question, conventional fluid. EVERYONE I know that has silicon brake fluid losses their brakes on the I-80 run from Sacramento to Reno over the Donner summit. That's a 7000' climb in 1 1/2 hours. The air in the silicon expands at the higher alititudes. Those who take back roads and use their brakes a lot for the same run don't have this problem. If your car is a trailer queen, go ahead and use the silicon. If you plan on driving it, I would use conventional.
Ken

[Bruce B.]

Re: C1 - Brake replacement

I have a hotrod 62 in which I use silicone brake fluid. I think it works as well if not better then the regular DOT 3 & 4 fluids. And it does not hurt the paint.I did replace all brake components prior to using the silicone fluid.

[Dave Suesz]

Last year I replaced my entire C1 brake system,

after a lot of thought I used DOT 3. As long as it is bled occasionally, it'll last indefinately.

[Gary Bishop]

Re: C1 - Brake replacement

I have been using DOT 5 for 15 years in our `62 and have had no problems. When we drove it to Steamboat Springs, from the east, we didn't encounter any brake fade. Last year I flushed the system with DOT 5 just to clean out the system.

[David N.]

Re: Last year I replaced my entire C1 brake system

Dave, Nice looking Corvette!!

David Nims

[Chris H.]

Re: C1 - Brake replacement

My 62 sat in "storage" in a coney Island for about 5 years as I had a couple kids and a two car garage in unrestored condition. I had been driving it though before that. When I picked it up the brake lines were empty and the wheel cylinders had leaked the fluid out. I rebuilt the master cylinder with a kit, had the rear cylinders sleeved and rebuilt the fronts with a kit and then flushed with alcohol and then flushed with DOT 5. Now running with DOT 5 with no problems.

[Rich Webster]

Re: Last year I replaced my entire C1 brake system

Thanks for all the input. Sorry it took a week to thank all of you. My laptop mother board died. Dell came to my house and did the repairs under warrenty. I have a second part to the question about brake fluilds. My master cylinder on the car is not an orignal type. It is a replacement GM model. Will the "copper crush" washer work to seal between the master cylinder and the block. Per the books the original setup had the master cylinder, reducing outlet nut and then the block. The master cylinder, reducting outlet nut, and the outlet block, have rings which I'm guessing will be squeezed into the "copper crush" washer making a seal. On the replacement model master cylinder it has a smooth outlet serface, and the outlet is reduced to accept the block. Will a smooth serface on the master cylinder mate with the block (and its rings) and make a seal?

[Roy B.]

Re: Last year I replaced my entire C1 brake system

Yes it should be OK