Brake fluid

[Skully]

I was reading the pros and cons of different brake fluids, what does everybody use and why. I use Dot 5, but I read that it makes the brake pedal soft. When you flush the brake system do you use something other than brake fluid. They also talk about dry and wet boiling of the fluid. What is the best for just cruising and all round driving, I know from the past dont get the brake fluid on the paint.

[Karl Bebout]

Flush with new brake fluid. Personally, I use just plain old DOT3 fluid, but then, I don't do road or track racing where I'm on the brakes that much.

[mikiec]

To borrow a phrase....

What he said

[Bob In Ct]

DOT 3, it's more tolerant of high moisture levels.

Bob

[Karl Bebout]

No, Wait. MAYBE the DOT3 fluid is the reason my car took off through the desert. It just couldn't get stopped because I boiled the fluid! YES! That must be the reason. Knew it couldn't have been the ding bat behind the wheel.

[Zoom This]

I use Ford Hi Performance Dot 3 and change fluid every year or so along with clutch master cylinder fluid. Ford Hi Perf has very good wet and dry boiling points.

[Bob Broberg SPF667 460BB]

Dot 3 and keep an eye on fluid color. As you know, old, moisture filled brake fluid turns a brownish color. I flush brake and clutch fluid about every 2 years, about 10,000 miles. We have a tendency to brake hard and use the clutch a lot.

AZ Bob

[Tom Wells]

Skully,

This is the one I prefer: http://www.valvoline.com/products/br...brake-fluid/28

I use it for combined street driving and track days. So far, so good....

Tom

[RedSnake351]

Originally Posted by Bob Broberg SPF667 460BB

... We have a tendency to brake hard and use the clutch a lot...

AZ Bob

Yea, Bob, but Dan tells me that you do this inside your garage while mouthing the words, " VAROOOOOOOOM, VAVAROOOOOOOOM!, over and over and over...

No wonder you need to change the fluids so often!!!
Ralph

[Danr55]

Ralph, be nice.. Hey, Are you coming out here soon enough to go to Laughlin with us this year?

[RedSnake351]

Originally Posted by Danr55

Ralph, be nice.. Hey, Are you coming out here soon enough to go to Laughlin with us this year?

Working on it, but may not be able to leave here till the 1st of November!
Ralph

[Bob Broberg SPF667 460BB]

Ralph, do you practice your routine in front of a mirror? You need some new material. Don't give up your day job.

AZ Bob

[PurpleVenom]

I wouldn't flush with other fluid. I used denatured alcohol, then put in the fluid to flush that out. Took about 4 bottles of fluid. Ok, here's what I learned on the different fluids, the short version:

DOT 3 & 4 - mostly used for street cars
High Temp DOT 4 - mostly for track cars
DOT 5 - a silicone based fluid that has a higher wet boiling point. Does not eat paint like the others.

I've used both the DOT 4 and DOT 5 on the track with my electric power brakes and have experienced no issues on the track with either. If you have power brakes, I do not believe you will notice a difference. Here are a few links for reference:

http://members.rennlist.com/911pcars/brakefluid.htm
http://www.afcoracing.com/tech_pages/fluid.shtml
http://www.trackpedia.com/wiki/Brake...enced_material

HTH,
Tim

[Skully]

Thanks for all of the info, I will put it to good use.

[bobcowan]

DoT5 is an old fluid that doesn't really have a use any more. It was used in race/track cars because of the higher boiling point. Harley used to put it in their bikes to protect the paint in case of a spill; they quit doing that 6-8 years ago.

There are some down sides to the 5. It doesn't like water. So when water does get into the system, it tends to pool, and end up in the calipers. That's a bad thing, as it gets hot and turns to steam in the caliper. Systems with 5 need regular flushing to prevent that.

5 is also compressable. Most drivers wouldn't notice that. But on the track you would.

The reason for 5 was the higher boiling point. The only option you had back then was 1 and 2. Racers used 5 despite the down sides.

Now you have plenty of options, with no down sides. Plenty of glycol based fluids have a boiling point around 600* or higher. Not many drivers need more than that on a Cobra. If you do, you probably have a design flaw.

There's a "new" fluid on the market, DoT 5.1. Supposed to by synthetic with the same properties of as glycol 4, , but have a high boiling point. I have not been able to find any of this. I use Wilwood fluid.

DoT5 DOES NOT mix with any other fluids. If you mix 4 and 5, it will clot in just a few minutes. I tried it. Most brake systems are cleaned and assembled with a glycol compatible fluid. If you want to use 5, you'll have to disassemble and clean with alcohol. Then re-assemble with 5.