I'm doing my brake system and bought dot 5 to replace the dot 3 since it doesn't eat paint...Many hours in painting the engine compartment I don't want to risk it...The "parts counter guy" said there is NO way he would ever consider it that I will have a spongy pedal and poor braking but I was told by some no difference will be noticed just don't mix it with other types of brake fluid which I knew...Anything else to consider. It's a street/strip car and ran almost 130mph,I don't want poor braking...Thanks in advance

Wish I had gone the DOT 5 silicon route. A stubborn leak at the MC connections has messed up my engine bay paint with conventional DOT4.

From what I've heard, DOT5 is a little slower bleeding due to viscosity. Bleed, wait a few hours for the bubbles to combine, bleed again. Once bled, it works fine.

Thanks for the info and sorry for your engine compartment getting messed-up...
It's amazing how much time it takes to strip,blast,repair,sand and paint just an engine compartment...Alot of cracked rough finger tips when done and I know I would be if I ended up seeing it get messed-up.

DOT 5 is the only way to go,just did a couple customers cars and it's worth it.It doesn't ruin your paint and the higher temp.benifits are well worth it,it's nice to convert over because it's a different color and it's thicker....no pedal difference and the benifits are definitely great.

If you need the inside spec.and tech.info.get ahold of Mastershake340 on here...he's a brake GURU....

the reason most people have trouble with DOT 5 brake fluid is because it retains AIR like DOT 3 does water. if you use DOT 5 leave a open bottle out in the sun for at least 1/2 hour to boil out the air that forms inside the bottles when it's shipped and handled. this is the reason it's sold in black bottles. or you can place a open bottle in HOT watter, about 200*, for about 20 min. when doing this you can watch the air bubble release from the fluid. some people tell me that it's boiling. that's not happening it's just the air releasing from the fluid. i use this method as much as possible.

when you install it in your car. suck out the old fluid in the master with a turkey baster or something like that, i use a old animal syringe that's rather large.

them pour in the new stuff and then bleed out the new fluid thru the lines. you can easily see the new stuff because it's purple.

use caution when bleeding the brakes. so SLOWLEY pump the petal so you don't form bubbles in the master.

also DO NOT ATTEMPT TO FLUSH the system with anything, the most often one i hear is alcohol. this will create problems when bleeding the brakes because it will compress more than brake fluid before getting hard and give you a spongy petal.

DOT 5 fluid will not gel when it's mixed with DOT 3. it won't mix with it eather. but they will not react to each other. when you mix them in a jar and shake they will look mixed but after time they will just separate.

hope this info helps. i have been using DOT 5, silicone, for over 10 years without any problems.

That's funny because our DOT 5 is shipped in WHITE 1 gallon jugs.We use it everyday in the vehicles at work.No problems bleeding it,nor does it give a spongy pedal.

with this new knowledge of air bubbles in the can, I may try it. I was always afraid of the spongy pedal that I always hear about.

Everyone I know that plays with old cars uses the DOT5 Silicone brake fluid and has for most of 20 years.
Never had any problems with a spongy pedal or fade.

My, my, my, what an enlightened view of DOT 5. Eight years ago most would be hating, now most are in favor. New and better things take a while I guess. I use it cause I hate the idea of paint remover coursing through 30 year old veins. Never a problem. Kim

One other point - because it does not absorb moisture, any that does get into your system may end up pooling somewhere - for example at your caliper etc. So there is a risk of localised rusting. It also costs a bunch.
I got 5.1 - mineral with equivalent hi-temp properties as 5.0, but much cheaper, easy to bleed, no risk of pooling etc. BUT - if it gets on my paint I may wish I went with 5.0....

the only reason i said it's in black bottles is because that's the only way i have ever seen it. i only buy it 1 quart at a time. i am sure somewhere it's available in white quart and pint containers also.

the air bubbles problem is the reason why it's not recommended in use on anti lock braking systems.

if anyone has any doubts about my statements do a simple test.
shake up some DOT 5 fluid. let it sit on the bench for several hours. now pour some, save some for later, into a container that's in boiling or very hot water. get the fluid up to around 200*. you will see air bubbles being released when it sits in the hot water. now let the extra fluid sit for a few weeks and do the water trick again. it will do the same thing as the freshly shaken fluid. i am sure some air will work it's way out by itself but there will be lots of air trapped into the system.

DOT 5's ability of retaining air is why you hear so many comments about how it will give you a spongy brake pedal.

one other thing to keep in mind it can allow water to stay in your brake system. over time the water in the fluid can mess your brake system up from the inside out. so every 4 or 5 years change the fluid. it also can get shaken up inside your master cylinder creating air bubbles. so if you brakes pedal starts to get soft. change the fluid and the hard pedal should return.

DOT 5 is hydroscopic, it will absorb water! I agree with Mr T2U and change every few years, esp w/ steel lines.

dot 5 here,everything new,bleed by myself,just took longer,as i first did gravity,then slowly pumped pedal with master cap off,best pedal i've ever had,manual front disc rear drum

..this discussion will never stop.
use Dot 3 with care and you will be fine
take the lady out with the money you save