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Hello all
Time to put brake fluid in my car what type of current brake fluid can be used?
Thanks

unless your car has been converted to silicone, DOT 3 or DOT 4.

Synthetic fluid also uses the DOT 3 and DOT 4 designations so the answer is to use a standard non-synthetic fluid unless it's been converted to synthetic.

The DOT3 and DOT 4 you see in all the stores are labeled synthetic. That is okay as all brake fluid is synthetic. It is the DOT5 you want to stay away from for a stock car, as bkasmer stated, as that is a silicone based product. That will cause problems with rubber seals not designed to handle DOT5 fluid.
I use DOT3 in my Patrician, buying the small, yellow Prestone plastic bottles available most places. The bottles say Synthetic like every other brake fluid out there, whether the are marked that way or not.

DOT4 can be used and mixed in too, it just has a higher boiling point. (Oddly there is now a DOT 5.1, which is more like 3 and 4 as glycol based, which would be okay too at an even higher boiling point)

I had system flushed and installed DOT 5, but started having problems with the stoplight switch. I had the brake system drained, flushed, and refilled with DOT 4, as I had for years without issues. But others swear by DOT 5. I just swore.

Because Dot 5 Silicone is inert they added a swelling agent that is supposed to mimic standard brake fluid. I suspect that is why there are some of these problems with brake light switches. New rubber parts wouldn't be affect but a reused switch might not respond well after being conditioned with standard brake fluid. However, I went through a number of switches with standard fluid so maybe some of these replacement switches are junk. It is a load bearing switch so if I was faced with that problem again I would substitute a relay to see if the switches simply are junk and can't handle the load.

One thing is definite - new brake fluid is not the same as the old stuff.