Ay reason not to run dot 5 in race car.Its only thing I have used in motorcycles since wit does not harm paint.Never had issue and guarantee if heat was issue lower MC being right under exhaust it would have shown up.Plus I ride so nice and easy never over speed limit or cutting up country roads.

If you think it needs a #5 on it,,,,,,, use 5.1 only in a racecar.

always ran 5 in go-karts when I was younger, but we had to as the road courses would boil 3 or 4. But I can't think of any reason to run #5 on anything else.

I was at a local track once and there was a guy pitted next to me..old '67 Nova, really a redneck-style run-what-you brung kinda deal, primered, etc. Guy walks over after coming back from a run and wanted to know if I had any pure antifreeze, not 50/50. I had about a quart left over so I give it to him, and I happened to glance over and he's pouring into the master cylinder. Said it works just as good as brake fluid. LOL.

All your brake manufacturers specifically tell you not to for what it’s worth....

I tow down some very long steep grades and lost the brakes due to the fluid boiling. That is truly a terrifying moment when the brake pedal goes straight to the floor. I changed the brake fluid to Wilwood High Temperature Brake Fluid, it never happened again.

Bob

quote:

Originally posted by mavman:
always ran 5 in go-karts when I was younger, but we had to as the road courses would boil 3 or 4. But I can't think of any reason to run #5 on anything else.

I was at a local track once and there was a guy pitted next to me..old '67 Nova, really a redneck-style run-what-you brung kinda deal, primered, etc. Guy walks over after coming back from a run and wanted to know if I had any pure antifreeze, not 50/50. I had about a quart left over so I give it to him, and I happened to glance over and he's pouring into the master cylinder. Said it works just as good as brake fluid. LOL.

Really! Wow. I have never heard that, and don't think I would try it. But ok!

If you’re out of brake fluid and it’s an emergency I always heard to use water. Only problem is you then have to remove it all from the system.

We had the same question years ago when were in Karting and stated as follows. Great info. We would boil the brakes all the time.

QUICK REVIEW:
The fact that DOT-5 silicone-based fluid doesn't absorb water (meaning that it isn't hygroscopic) is NOT AN ADVANTAGE. Instead, water pools in the lowest point of the brake system, puddling. This causes rapid corrosion, and it therefore needs to be changed MORE OFTEN. Water than finds it way into a low spot in a caliper boils at only 212 degrees F.

DOT- silicone based fluid is more compressible, leading to slightly less pedal feel.

Most racers with experience also speak of the problems using DOT 5 after previously using DOT 3/4 can cause. Due to different seal swelling agents, many times leaks quickly occur in a system after changing from Glycol-Based (Dot 3/4) fluid to DOT-5.

DOT-5 fluid is more difficult to bleed, since it more easily retains tiny air bubbles. These bubbles act as nuclei that attract other small bubbles, that then turn into large bubbles. Bubbles are air, and are therefore very compressible.

DOT-5 fluid also tends to aerate from vibration... a concern when driving a kart with an engine that vibrates so bad your teeth almost chatter (DOT-5 attracts air bubbles like a magnet).

Most racers are using high-quality DOT 4 fluids such as Castrol's top-of-the line product or Motul, etc. FORD makes an excellent DOT 3 fluid that is cheap called FORD HEAVY DUTY.

However, the original question remains: WHAT DOES TOP-KART SPECIFY FOR USE WITH THEIR BRAKE SYSTEMS?

The answer, according to an email I received from Comer/Top-Kart today is....
GLYCOL-BASED FLUID (DOT3 or DOT4)

Aside from that we had the ENTIRE operation Stolen. All 5 karts,tools, spare parts, racing suites, 2 spare engines. Only thing left were dust balls. *** about the situation was the detectives knew who stole it and would not give me any names. That was the end of racing for the family.Only recovered 2 stripped karts back.

This message has been edited. Last edited by: TD3550,

Halfscale dragsters sells and recommends DOT 5 for their jr dragsters.

yep and the COPOs come with DOT 5 in their master cylinder as did my Undercover dragster and MPR built Firebird and it's all I run.

Great pedal and the fluid looks like new when I flush it before the start of every season unlike DOT3, 4, 5.1 which is black and stinks.

We use 5.1 in our stuff.

I had Strange Engineering tell me to run Dot 5.

I could care less what people run hell put water in it for all I care....But MARK WILLIAMS says don’t do it....Yeah my UNDERCOVER came with...it might work fine on long shut downs and running 4.80s...but running very short shutdowns and running 4.30s and double entering....YOU AINT GONE STOP....

if you can't stop running 4.30s with a short shutdown, it ain't because of the brake fluid you run and you're car shouldn't be on that track.

I see Willwood doesn't recommend it for race cars:
https://www.wilwood.com/PDF/Pr...dot5_brake_fluid.pdf

It appears to be marketed to the show car crowd.

I heard or read that in the 70s

Using wilwood brakes on a 4.30s dragster is a sure bet you won't be able to stop with a short shut down.

That said, I know several TD and TS racers with DOT5 fluid in their master cylinder.

Run what you want like stated...

quote:

Originally posted by bradsc1954:
I had Strange Engineering tell me to run Dot 5.

Funny website says 5.1...

quote:

Originally posted by Bucky:
I see Willwood doesn't recommend it for race cars:
https://www.wilwood.com/PDF/Pr...dot5_brake_fluid.pdf

It appears to be marketed to the show car crowd.

Not ONE DRAG RACING BRAKE MANUFACTURE recommends it...for a reason