.Re: Litmus Paper Test for Dot-3 Brake Fluid

[Guest imported_Speedster]

In another thread, recently I mentioned how Dot-3 Brake fluid absorbs moisture and Dot-5 doesn't. I noticed that there is now a way to test for the amount of water in Dot-3 (I saw it on TV). You can purchase a litmus type paper that is dipped into the fluid and gives an indication of it's boiling point. The big problem with water in the Dot-3 is that it lowers the boiling point of the fluid, which can greatly reduce brake efficiency, as well as decay or corrode rubber and metal system parts.

[Guest bkazmer]

Or use fresh DOT4 - it's still a mineral type but has a higher boiling point

[Guest JT]

Castrol LMA DOT 4 is a good choice.

[Clipper47]

One of the problems that I have read concerning DOT 5 is that while it does not absorb moisture like DOT3 and 4 it does mean that any moisture getting into the brake fluid system will gravitate to low points and cause corrosion there. Therefore I assume that water may not be detectable with litmus paper if a sample was taken from the master cylinder. I change the fluid very two years in all of my cars and have not had any problems. I have been considering using DOT 5 in the Packard just to avoid spillage damaging the paint. I think "Mr Pushbutton" has commented on another forum that he used DOT5 in the collector cars he maintained and had excellent service from it so he would be a more credible authority than me.

[Guest Randy Berger]

Is DOT-4 still hazardous to paint??

[Guest BigKev]

Dot-4 is used in race cars do to it's higher boiling point to reduce brake fade. The Dot-5 can be a bear to bleed te air out of as compared to Dot-3. Also Dot-5 tends to ruin brake switches over time. So you may have to switch to pedal activated switch instead of a pressure switch.

[Guest JT]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Is DOT-4 still hazardous to paint?? </div></div>

Yes

[Clipper47]

Yes

[Guest imported_Speedster]

Looks like No one is interested in the Litmus paper test. <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" />

Oh Well, I tried. <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" />

Sure seems like everyone is eager to reopen the old question of 'Which Dot to Use' tho. <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" /> <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Guest imported_Speedster]

In case anyone is interested I found some online for sale, but it's too expensive for me. <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" /> This is the first time I had seen a price for it. <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" />

http://www.sjdiscounttools.com/psfascar1100.html

[Guest Silverghost]

Dot 5 (silicone ) does NOT absorb water out of the air. Traditional Dot 3 or 4 is hygroscopic and will actually attract water; sucks it out of the air. In addition it is harsh on all paint...almost like paint remover. Dot 5 (Silicone) is harmless to paint.

I have a speedboat trailer with hydraulic surge brakes on four wheels...the trailer is dunked in water to launch and pick-up the boat...

In one year...the brakes siezed solid.(using Dot 3 )

The steel lines rusted-out from the inside out.

I re-built this system ten years ago...used stainless steel lines etc. Silicone Dot 5 was installed at this time....

Long story short 10 years and counting and the system is still fine. No more water absorbsion no more siezed cylinders or rusted out lines.

This should tell us all something.

I have heard of the brake switch problem...but i have not seen this in any of my old cars.

I use Dot 5 Silicone in ALL my Classics and older cars. If you don't use these cars for long storage peiods (like Winter) Silicone Dot 5 is also he way to go.

A far as being hard to bleed Dot 5 Silicone...

This is a myth...unless you are a madman amd pump he brake master cylinder very rapidly to bleed them; and form bubbles.... I always try to use a quality Pressure bleeder, or pump slowly.

The only problem I have ever heard with Dot 5 silicone is bad reactions with some inferior reproduction China Made rubber compounds.Always use a name brand cylinder repair kit. Lockheed, wagner,etc. This could also explain the hydraulic bake switch problems reported here. What is NOT made in China these days?? I have heard of the paper test...but never used it. There is also a very costly hand heald spectrometer to test for water % that Car dealers use.

[mrpushbutton]

Clipper47--if you are changing the DOT-3 fluid in your vehicles every two years you are not going to suffer the problems from moisture that have been discussed often in these forums. Not many people change their brake fluid, it's sort of a "fill 'n forget" kind of thing until there's trouble. Every two years is a good proactive program for dot-3. I couldn't do it with 150 cars though--not enough hours in the day, ergo my admiration for silicone dot-5

[Guest JT]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Not many people change their brake fluid, it's sort of a "fill 'n forget" kind of thing until there's trouble. Every two years is a good proactive program for dot-3. </div></div>

I wish I had gone with silicone on my last brake rebuild but the company that resleeved my master cylinder recommended staying with Dot 3 or 4 for some reason.

I know it's a pain to switch to silicone but it would be easier than changing the fluid every couple of years.

[Guest imported_Speedster]

.

[Twitch]

I've been using DOT 4 for decades with no problems. Every car at some time requires brake work so what is the big deal of replaceing fluid when you do brakes?