Suffolk350z

So I changed my clutch fluid used dot 4 instead dot 3 thinking higher boiling point. in traffic sometimes clutch pedal seems to get soft. So I put in dot 4 pedal seems smother also easier to depress clutch. So ? is should I leave the dot 4 in or go back to dot 3. not sure if pedal is softer because new fluid or using dot 4 I like the stiffer pedal. My clutch line is heat wrapped. 2004 roaster 45,000 miles all stock.
Thanks

dkmura

iTrader: (64)

DOT 3 and 4 rated brake fluids are interchangeable.

Suffolk350z

I know that that is why I used DOT 4 instead of DOT 5 but dot 4 is also thicker then dot 3, wondering if clutch master is good with thicker fluid.

terrasmak

iTrader: (8)

Didn't know it was thicker , never noticed one to ever be thicker. I've been using ATE blue in mine for years

dkmura

iTrader: (64)

DOT 5 brake fluid is NOT interchangeable, so don't use it in a system that has DOT 3/4 fluid in it. As for the viscocity of the fluid itself, it shouldn't make much difference. Each brake fluid has a particular wet and dry boiling point and the higher the better for performance purposes.

myork

iTrader: (5)

You can use DOT 5 as long as you completely flush out what is existing.

DOT 5 might be a little overkill for a daily driver, but it is a true synthetic (not glycol based) and is not hydroscopic so it doesnt absorb water. Higher boiling points over DOT 3/4 as well.

dkmura

iTrader: (64)

DOT 5 brake fluid is not recommended by Nissan for use in the Z33. It's also impossible to completely flush all traces of DOT 3/4 fluid from a brake system. Overkill indeed, I don't use DOT 5 in either my street or race Zs...

terrasmak

iTrader: (8)

I doubt the seals are compatable, now I know dot 5.1 can be used.

dkmura

iTrader: (64)

This thread has become overly complicated because of all the contributions. The original question was whether DOT 3 or DOT 4 brake fluid was better for use in the clutch line? To recap:

-Either can be used (plus DOT 5.1 if it's available), as they are all poly glycol-based fluids which is what Nissan designed the clutch and brake lines/seals for.

-Viscocity is not a key factor in performance of brake fluids, but dry and wet boiling points are. The higher, the better, for use in a high performance vehicle.

-This board has several threads on brake fluid recommendations, so a search will help determine what the best combination of cost, performance and durability will be on products available in YOUR area of the country.

i8acobra

iTrader: (6)

You got it backwards. DOT 5 is silicone based and is NOT recommended. DOT 3, 4, and 5.1 are glycol based and ARE compatible.

dkmura

iTrader: (64)

You're right- corrected!