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Discussion Starter · #1 ·
I have to replace my front brakes and the fluid is near black. I can't remember if it's recommended to go with DOT 4 or 5 when using the Indy SS braided lines. Anyone?
 

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They'd be teflon lined, so I don't know why you couldn't use whatever you wanted.
 

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betterthanyou said:
DOT 3 or 4 ONLY. You cannot use DOT 5 in a system previously filled with DOT 3 or 4.
yes 3 or 4 ONLY

5 is for racing with short drane intervals and should never be used on road.
 

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trooper T/diesel said:
betterthanyou said:
DOT 3 or 4 ONLY. You cannot use DOT 5 in a system previously filled with DOT 3 or 4.
yes 3 or 4 ONLY

5 is for racing with short drane intervals and should never be used on road.
My 03 harley uses dot 5.
 

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I dont know about the interval thing, but 5 is unique since its silicone based while the others are polyethelene glycol. If I recall correctly the problem with using DOT 5 in none DOT 5 is that it damages the seals. DOT 3,4, and 5.1 are all compatible.

As far as 5.1 vs 4, vs 3 goes I wouldnt bother with 5.1. I didnt even bother with it on my bike and I beat the brakes on that thing. Just go to your local auto shop and get 3 or 4. Which ever is on sale. I personally like to bleed my brakes once a year or so and when I do the DOT 3 is still fine, and although I'm sort of throwing away money doing it so often I throw away less by putting 3. Gives me a reason to work on the Isuzu and bike I guess.
 

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betterthanyou said:
DOT 3 or 4 ONLY. You cannot use DOT 5 in a system previously filled with DOT 3 or 4.
You can if you flush it with alcohol, but some people who convert just do a drain and fill.
 

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trooper T/diesel said:
5 is for racing with short drane intervals and should never be used on road.
Or for vehicles that spend extended periods in storage so there's no worry about moisture absorption.
 

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for a road going auto you want brake fluid that absorbs water.
 

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Agreed. If you use DOT5 any moisture in the system will find a place where it likes to sit and will corrode right through your lines or fittings. Use DOT 3 or 4 only and any moisture will be mixed in the oil and the anti corrosion additives can do their job properly.
 

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Water is immiscible in silicone so you'd know there was water in the system long before any corrosion happens when the droplets boil, and your spongy, compressible silicone brake fluid suddely gets even spongier and more compressible. Glycol fluids are less compressible to start with and degrade more slowly as moisture is absorbed. The glycol fluid is hydroscopic though, so it will quickly self-contaminate through absorption from the atmosphere and diffusion through unlined brake hoses. A closed system of silicone fluid stays water-free pretty much indefinitely.

There's pros and cons to both types of fluid.
 

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Discussion Starter · #12 ·
Thanks guys. I thought I remembered reading posts from guys who had done this upgrade that claimed better braking performance with DOT 5. Since it's been 4-5 years since I got my braided lines, I honestly can't remember. Is there a difference that one can tell? If not, then 3 or 4 is good by me.
 

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Price alone is enough reason to stick with DOT 4.
 

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During hard sustained performance braking and boiling your black old moisture laden brake fluid is all the reason for performanace fluid and frequent fluid changes. During hard repeated performance braking, when your pedal goes to the floor and you pump madly and still don't have any brakes, thank your discount walmart brake fluid or stock ancient OEM fill.

Or like 98% of the people who drive on the same brake fluid for 100,000 miles that turns as black as motor oil, it may be fine for your daily sunday drive. I'll take the much higher boiling point and moisture absorbtion resistance

Blue Dot, all the way. They also sell yellow, so bleeding your brakes with alternating colors makes full fluid flushes easy.

http://www.amazon.com/ATE-Super-Racing- ... B0007SN6F6

Run this in my Porsche 911, and all my other daily driver cars.

You may not need it, but then again, it's pretty cheap insurance.

Heck, it's only your brakes.
 

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Discussion Starter · #15 ·
Thanks all....DOT 4 it is. I like what I read about the blue dot. How much would I need to get for my mechanic to flush all brake lines in my Trooper?
 
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