Ok I have a few questions about this and some info to give. First what brake fluid are you guys using? Next brake fluid is rated in wet boiling point or dry boiling point (or resistance). What exactly is wet and dry stand for in this?



FU Tuning

I use a semi-synthetic DOT4.

The most important thing people need to know about brake fluid is that DOT 5 (or any other silicone based fluid, if you can find any) can't be used in our cars. The system has to be made for it.

DOT3, DOT4, and DOT5.1 (which shouldn't exist as it's too easily confused with DOT5) are all non-silicone based and can be safely used or mixed.

Well after a little research I found out what wet and dry stand for in this. Dry is fresh fluid not exposed to moisture. Wet it fluid exposed to moisture. I'm installing SS brake lines on my 01 Z. Had to get some brake fluid today. Did some reading on the bottles. Comparing cheap stuff to better stuff. I got Valvoline synthetic. It had a much higher boiling point (wet and dry). It was only a $1 more than the cheap stuff.



FU Tuning

Yea, its "dry" the hole time its sealed in the bottle. But as soon as you open it, the mositure in the air makes it "wet". I personally just grab a bottle of DOT 3 off the shelf.

Tinkles wrote:Yea, its "dry" the hole time its sealed in the bottle. But as soon as you open it, the mositure in the air makes it "wet". I personally just grab a bottle of DOT 3 off the shelf.

I usually do as well. After reading the bottles, most of the normal off the sheft wet boiling points were 284 F. The one I got is 311 F. Of course not a huge difference, but still better, and still off the shelf.



FU Tuning

I think I'm using the same stuff. Silver Valvoline bottle, right?

Thats what I have....the Valvoline SynTech, something like that, dot 3/4 synthetic blend.

It made a world of difference in my T/A, since my brake lines are so close to my header. I would boil regular fluid, has not happened since I flushed and put that stuff in. So the temp difference might be slight, but it was enough to save my buns....

I use the Valvoline synthetic too.

To add to what weasel said about not using DOT5- its because it doesn't absorb moisture. Everything else does, so you won't get water "pooling" at any one point in the system and rotting it from the inside out. DOT5 can be used if you're going to be flushing the system regulary, like once a week. Its mainly for non street cars that see high brake temps.



Edited 1 time(s). Last edited Friday, May 09, 2008 8:42 AM

I thought the reason the silicone based wasn't good for us was destroying seals present in ABS systems. If that's the case would silicone be okay for a non ABS car?

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<<<<<2003 Sunfire Sedan>>>>>

That too. The whole system needs to be designed for DOT5, regardless of ABS or not.

I have synthetic DOT 4 in mine

Quote:

DOT5- its because it doesn't absorb moisture. Everything else does, so you won't get water "pooling" at any one point in the system and rotting it from the inside out. DOT5 can be used if you're going to be flushing the system regulary, like once a week. Its mainly for non street cars that see high brake temps.

Its the fact that its not hygroscopic. Formula cars, LeMans, GT cars etc.. use dot 5. But thats flushed out after pretty much every race. its dangerous in a daily driver because if water pools it will boil and your going to lose your braking ability. Water forms because of the heating and cooling of the brakes essentially causing sweat in the calipers and lines.

hygroscopic fluid absorbs the water so it isn't a problem.


that being said I use the synpower DOT4, keeps my brakes strong in autocross.along with the powerslots.


-Chris

yes, but the more water the brake fluid absorbs, the lower the boiling point gets. so it is important to flush it often anyways, if you are getting it anywhere close to that boiling point.