What type of brake fluid?
 

Hi Guys
Being a new SPF owner can you tell me what type of brake fluid I need for my 2005 SPF? I need to top up the master cylinder.

Thanks for your help.
Stu.

DOT 3 is standard. Any name brand will do.

Unless the previous owner upgraded to hi temp fluid, like Wilwood DOT 5.

Better to ask the previous owner first.

Jim,
Thank you!

Stu.

Dot 5 fluid if you have disc brakes on your vehicle.

Yes I have 4 wheel disc brakes. Thank you for the information!

Stu.

Stu,
You really need to know what fluid is currently in your system before adding anything. Read this article: click here. You can cause some real problems by mixing dissimilar brake fluids, and DOT 5 is very different from DOT 3 & 4.

Not to pick on this post, but that is really bad advice. Disc brakes have been around since the '60's and they didn't have DOT 5 back then. %/

I know Dot3 and Dot5 are not compatible. Dot5 is silicone based. My problem is I have no way of finding out from the previous owner. I have emailed the SPF dealer that sold the car originally.

Thanks guys
Stu.

Stu, congrat's on the new ride! now's a good time to just flush your brake lines. use something good. Wilwood or ATE make excellent brake fluid. don't forget to do the clutch also.

This is good advice. Flush the system so YOU know for sure. Don't guess about your brakes.

Excellent advice guys!! Thank you!

Stu.

Stu,

If you're feeling brave, take some of the fluid from your car and put it on a painted object you don't mind being ruined. If it damages the paint, it is likely DOT 3 or 4. If it does not damage the paint, it is likely DOT 5. You could test the paint with DOT 3 fluid as a control for the test.

not to get defensive either, but SPF 1950 wasn't around in the 60's. Common practice from 2000 and up was that disc brakes used dot 5 and hyd. slave cylinders used dot 3. I agree, to be safe, purge both systems and use dot 3 for the hyd. clutch and dot 5 for the brakes. Manufacturer recommends to flush the salve cylinder every 1-2 years anyway as that fluid for some reason always seems to get very dirty.

Actually, there are some valid reasons NOT to use silcone brake fluid. A high quality DOT 4 is sufficent. While Glycol based fluids do absorb water, silcone does not. That is not an advantage in cars that are well maintained as the glycol holds the moisture to be flushed out when changed as a high performance car should be. The silicone allows the water to gather in your caliper bores and corrode. Many people who have gone silicone are surprised to find corrosion, "I thought silcone didn't absorb water?" they say. They are right, it does not absorb water, but moisture will still enter the system and find its way to the lowest point in your brake system. Good old DOT 4 holds the water in suspension to be flushed away.....

Use a brand name high temp DOT 4 fluid for the street. Racing fluid is made to be changed often as racers do. Regardless, something like an SPF is worth a brake flush every three years or more often.

I use ATE Super Blue. Reasonably priced and fairly high-temp. Good for sports cars.

Do not use silicone fluids. As stated above it does not absorb water, but water still collects and then pools and forms rust.

Do not think that disc brakes should use DOT5, just because the big three went to DOT5. They have many competing performance, financial, production, and liability needs that force compromise. DOT5 is not superior in performance, even though it is newer. DOT5 basically sucks for sporty driving.

Do flush your entire system if changing to DOT3 from DOT5. The ATE Super Blue is blue, so you know when it has displaced any residual old fluid. I also buy the ATE yellow and can therefore tell when I have completely flushed last years fluid out. Easy to alternate between blue and yellow and you know when your system is fully replaced with new fluid.

Thank you all for your comments. I did find out from the dealer that the car was prepared with Dot3

Thanks again everyone!
Stu.

Not exactly good advice.


This is pretty good advice. It's probably a glycol based fluid. That's pretty much the standard, and I would think a pro builder would use that. But, I would call and find out.

Disc or drum use the same type of fluid, doesn't really matter. But very few vehicles use silicone based 5.

I would have to disagree with that, too. Every car I've ever owned has used glycol based. And I'v owned 5-6 that were built after 2000.

Harley used to use silicone in their brake systems. But even they have switched over to glycol. My '06 Dyna uses glycol; the owners manual calls for DoT 3. But both of my '97's used silicone 5.

This is very true. Silicone is hydrophobic, and glycol is hydrophylic. Water is also heavier than most glycol brake fluid. So all the water ends up in the caliper. Once there, under hard use it heats up and turns to steam. Then you lose your brakes.

You cannot mix silicone and glycole - they clot.

silicone fluids tend to be a bit mushy, too. Not sure why that is, but they appear to be slightly compressable. I never noticed it on my Harley, and I'v never used it in a car.

The only differance between 3 and 4 is the dry boiling point. Once they get "wet", they're pretty close to the same. For street use, 3 or for will work fine. For track use, step up to a high temp fluid like Wilwood or Motul.

About the only advantage to silicone is that it won't eat paint as quickly as glycol. If you're building a show car, 5 might be a good choice. If you do use 5, make sure you flush it regularly. My Harley's got fresh fluid every year.

If you are planning on just street driving, any Dot 3 or 4 fluid will work fine. If you plan on any track days or spirited driving you should definitely get High temp fluid. Calipers can get VERY hot on track days and you can easily lose your brakes with the standard fluid.
I've filled my system with DOT 5.1 Non silicone fluid. It is supposed to be compatible with Dot 3 and Dot 4 fluid and is rated to 570 degrees. Some of the better race fluids are rated to 700 degrees but you probably won't need this protection level unless you are racing seriously.

Bob

Great thread. Looks like alot of us are learning good info on brake fluid. My BDR recommends use of dot 5 for the brakes. All the custom motorcycles I built used dot 5. I knew Harley went to dot 4 in approx 2006. Great info. Thanks for the schooling.