what is the best brake fluid to have in your C3? I am not a road racer, but I can be hard on it every now and then. I am limited by my insurance to how many miles I can drive it a year so I want something that is going to hold up and not suck up a lot of moisture and corrosion. I have read that the silicone based is the best for high performance, but I know there has to be a draw back, else it would be standard.
The polyglycol (normal) is what I have now, every year I suck the MC almost dry and pour in a fresh batch on my other cars but I have been reading about all the brake nightmares on the vettes and I'm not sure if I am inviting trouble.
what are you guys running and how often do you change it? the car will do more sitting than driving, although I do start and bump it around the garage about once a week to keep the calipers wet.

 

The drawback with the silicone stuff is that its expensive and that polyglycol (which is much cheaper) works just as well under normal conditions.

 

I've been told that the best fluid is Ford's brand (horror's!) you can buy through their dealers. Supposedly many race teams use it and wrap a different label on it.

Realistically, any DOT 3 spec fluid should do what you want.

A good thing to do on a C3 is at least once a month while it's stored is to pump the brakes several times to make sure the seals stay moistened and everything stays lubricated.

 

Silicone brake fluid compresses, doesn't mix, and IMO you'd be just as well off with a bad hose. Castrol GT LMA Dot 4 will probably exceed your needs, it's cheap, and available everywhere.

 

Just completed doing a break fluid in all of my cars the other day, plus my C3 . Used Prestone Dot 3 Synthetic ( not silicone ) Synthetic seem to be the way to go today, it is compatable with brake fluid. Get youself a pressure bleeder and you will find yourself doing the brake fluid bleeding more often ,as required on cars today with ASB. Makes it a real simple job.

 

And this product has less affinity for water.

 

69 - manual brakes - DOT 5 Silicone - 3-4 years use - absolutely no complaints. Nice hard brake pedal, great stops, no moisture issues. Wouldn't use anything different.

 

like pws69,
74 - power brakes - DOT 5 Silicone - driven less then 5000 mi/yr - absolutely no complaints. Nice hard brake pedal, great stops, no moisture issues. Wouldn't use anything different. also won't strip paint!

some "tricks" to bleeding silicon:
1 if system ever had dot 3/4 installed, it must be completely cleaned; this means complete disassembly of MS and calipers for best results.
2 eventually purchased diaphragm bleeder, was a must have for me ("motive" type power bleeders without a diaphragm will whip air into dot 5)
3 put fluid in pot on hot plate to drive off air before installing in system
4 with bleeder valve open, push pistons back fully into bore several times to help evacuate all trapped air

leave out any of the steps above and you may get into the "nightmares" described.
if you stay with a hygroscopic glycol, keep it clear - change often, pump pedal regularly, and keep off paint and you'll be fine.
in the end, dot 5 is not as good as other types for racing, but works great for the way many of us drive our vettes.

 

thanks for input, I would much rather hear about it than experience it! Now, hopefully I can save the DIY time for all the other issues!

 

L82Shark;
Don't overlook the fack that you Must!!
(if system ever had dot 3/4 installed, it must be completely cleaned; this means complete disassembly of MS and calipers ) Have you ever taken your calipers apart? If your going to do that just buy new Stainless Steel Calipers , much easier and you never have to worry about leaks again. I replaced mine 26 years ago and have never has a leek or a problem.
Your getting into quite a job just to replace your old fluid with Silicone. Way easier to just bleed the system every 3 years with fresh Dot-3.

 

not currently having any problems, was just wondering what everybody was running and what results they were having so when I do have a rebuild I know which way to go. I'm not sure what is in there now, I've only had the car for a few months. Anyone know a way to check and see?

 

L82Shark
Not 100% sure but I think Silicone brake fluid may be Blue or another color instead of clear. Somebody that has changed may know if its a fact or not.

 

believe that's correct, the silicon has a blue or purple dye added. if dot 3 or 4, it can be almost clear to nearly muddy brown in color. it's supposed to do that as it absorbes air letting you know it's time to change. don't know of a test, per se, but you might see if it will strip paint (on a test piece). chances are it's not silicon

 

[QUOTE=dariopop;1562957154]L82Shark
Not 100% sure but I think Silicone brake fluid may be Blue or another color instead of clear. /QUOTE]

Good question regarding "how do you determine whether you have DOT 3 or 4 vs. DOT 5 Silicone in your brake system ?". I had this discussion just the other day with someone and could not get a for sure answer. I too would like to hear the correct answer.

 

My silicon brake fluid (purchased from Stainless Steel Brake Corp.) is purple.

I had an all new, dry brake system (brakes, lines, MC, etc) and I decided to use silicon because it doesn't absorb water. From what I read, it is a good fluid to use if you don't plan on driving the car very much. I would not have used it if I had a brake system with DOT 3 or 4 because of the problem of cleaning out the brake system before using DOT 5.

 

I have used DOT 5, Silicone in most of my classic cars for more than 20 years and have been very pleased with it. I've used it in every thing from Corvettes to Mustangs and even Harley's. I usually purchase it from VB&P, but most good autoparts stores carry it or can order it for you. It is no more expensive than quality racing brake fluids. The only thing I don't use it in is a car with ABS or one I race, but that's another story.

I typically start with a new set of calipers (or wheel cylinders) and flush the lines and master cylinder with isopropyl alcohol until it flows clean, then just add silicone until it comes out of each line. I think I do a pretty good job of flushing, but I can assure you I'm not perfect... and yet I have never had an issue with contamination or mixing of fluid. You be the judge how much of an issue it is.

Yes you do have to be a bit more careful when bleeding with Silicone as it does retain bubbles longer than glycol based fluids. But I've used the manual pumping method, gravity bleeding, and a pressure bleeder with Silicone and found all to be little more trouble than other brake fluids.

I believe that Silicone has a place and for me, with a number of occasionally driven vehicles, it has saved many hours of maintenance and headaches. I even autocrossed my '73 Corvette for three years in Hawaii with Silicone in it and never had an issue. A couple of my vehicles get driven less than a hundred miles a year, but they always have a good solid pedal and no leaks. I guess I'm just lucky...

I use DOT 4, ATE, Super Blue Racing in my ABS equipped cars.

As far as telling if you have Silicone or not, put a small amount in a clear jar with some known DOT 3 or 4 fluid. Shake it and let it sit. If it quickly separates, it is likely Silicone. If it doesn't separate, it is not Silicone.

By the way I learned about the use of Silicone back in the early 80's when the DoD started using it in all of their vehicles that had hydraulic brakes to reduce maintenance. We bought the stuff in 55 gallon drums!

Good luck...GUSTO

 

I have been using silicone brake fluid in my C-3 since 1982 when I installed VBP SS sleeved calipers. Only the rears have been rebuilt (once) - fronts have never been touched since installed. Replaced the MC with a new one back then at the same time, and all hoses.

I just bled the brakes last weekend. I only did it because it had been so long since they had been bled. It had been 8 years more or less. Bought a Motive from VBP. Only a very tiny, tiny bit of air in the left rear and a couple of small bubbles in the left front. No contamination noted in the fluid that was replaced. I was pretty suprised at how small the amount of trapped air was after all this time.

Do a forum search on the Motive Brake Bleeder. It is an awesome product. Takes what was a real PITA job (Forget a Mity Vac bleeder on Corvette calipers - just doesn't cut it) and turns it into a 20 minute job.
Well worth the money spent.

 

Motive Brake Bleeder. It is an awesome product

 

The best brake fluid is one that will meet your needs. I doubt you need a super brake fluid with a boiling point of greater than 500 degrees. If you’re hitting those sorts of temps on the street we would have to discuss pad material, stainless steel brake lines, and ducts to cool your brakes. However, from your description “not a road racer, but I can be hard on it every now and then” you have not had issues with brake fluid boiling.

Therefore a racing brake fluid is probably not what you want. Brake fluids designed for racing are very expensive and it is expected you will change the fluid frequently.

Therefore best for you may be a non Hydroscopic fluid. I would have to agree with TheSkunkWorks when he said: “Castrol GT LMA Dot 4 will probably exceed your needs, it's cheap, and available everywhere.” The specs on Castrol GT LMA are: DOT Rating 4, Dry Boiling Point 446°F, Wet Boiling Point 311°F, it is compatible with other fluids, and “cheap”.

How often to change it? My experience shows that Corvettes that sit in storage leak more than Corvettes that are used. Once a year at a minimum would be my best advice.

 

Is bleeding the brakes very hard? I'm having some brake trouble w/ my '70 and was going to take it to a brake shop to have them fix it but if I can do it myself, I'd do it...

I saw this ad on craigslist for a 'one man brake bleeder'

http://phoenix.craigslist.org/pts/488038729.html

has anyone ever used this type of bleeder? The ad makes it sould simple but that rarely means that it is...