mikecamp

I'm starting to reassemble my 73 project and was wondering what is the best brake fluid to use. I have replaced the master cylinder and brake calipers with new ones. I'm old school and have always stuck with the traditional fluids but with all the new synthetic fluids I'm not sure old school is the best way to go. Any input would be appreciated.

dar322

i'm no expert, but wagners has been around for a long time. i'd go with whatever you feel comfortable with.

C2C3PO

When I researched this very same thing about a year ago I found a chart that showed the boiling point of all the respective traditional fluids and believe it or not Motorcraft Heavy Duty Dot 3 was one of the highest.
It was also easy to find.

Mike Ward

All brake fluid is 'synthetic'. There is no clear winner in which type or brand- just as there's no 'best beer'.

Marlin

Get valvoline brake fluid. It mets the Dot4 spec but cost the same as most Dot3's.

Dot 3 and 4 can be mixed so you are not stuck with one. Dot4 can handle more heat than dot3 so for the same price its a easy choice.

Vette5.5

Most name brand DOT 3 or 4 is pretty good quality, and compatible with each other. Wouldn't use old school DOT 5 silicone though, as really considered long since out of date. Wont mix with anything else, and wont absorb moisture. Absorbing moisture is really a good thing, as easy to bleed the system once in awhile. Silicones tend to leave crud laying in the system low spots, causing problems.

Shark Racer

It's more important that you flush it regularly as opposed to buying "the best stuff".

I use ATE Super Blue and Typ220. Started for my track cars, but the color change between the two fluids helps to determine when you've got fresh fluid coming out.

gkull

Use the higher temp fluids like Wilwood 580 degree and just bleed your brakes periodically to keep water free in the pistons

redvetracr

waste of money for a street car...

cottoneg

TheSkunkWorks

For most street duty, Valvoline DOT 3-4 will do just fine.

gkull

I keep forgeting that everything east of Denver is flat land. I can change a mile of elevation in a short time and brakes really get hot.

Also the 580 is only $10 bucks. I run AP which is 600 degree and much more money

Shark Racer

Not everyone tries to do donuts in the traction circle either.

cottoneg

Maybe it is just the people I know, but none are boiling their brake fluid. Most fluids are hydroscopic and will absorb moisture. I would doubt many flush theirs on a regular basis. So, flushing the fluid for a street driven car is probably a first step. Time trial and racing will require it much more often. Which is why I like the Super ATE, blue, clear fluids to be sure you have a good flushing of the old fluid.

If mikecamp is still having issues, then he might have to consider things like removing the rubber and going for steel braided lines (not a bad idea during reassembly anyway).
Running duck work back to the calipers for increased air flow to cool the brakes. Maybe even the inserts on his caliper pistons so there is not is less heat transfer to the brake fluid.

One thing I am not sure of, so I will ask. Do racing brake fluids absorb more moisture? I thought I read that. The assumption was that race cars bleed their fluid on a regular basis so it wasn’t an issue.

I guess my point is for street duty, any good brake fluid will work. And using a product made for racing on the street is not always a good idea.

rponfick

This subject always reminds me of "which is the best oil for my car".

For street, I would think anything would work, except, maybe 10-40W. Too thick for steet.

Ralph

69 Chevy

Close but no cigar. The correct term is hygroscopic...that which takes on moisture.

cottoneg

Thank you. And that was my point. The brake fliuid will take on moisture and lower the boiling point. It will also cause rust and pitting if you do not have stainless steel calipers.