Opened up the new mopar action and leading off tech was a question about mixing the silicone stuff with dot 4 and down. Eberg basically said everything people say about the stuff is wrong, to just use it no matter what. Everything from not mixing, to gelling, to having to flush with alcohol, is completely wrong he says. Having read his stuff for 25+ years, I find his insights to be pretty darn good.

I have a nice paint and would much rather use the silicone because of that. Really nice paint.

I ordered up a bottle of dot 5 to do my spring fluid flush. Right on the bottle it says it doesn’t mix. This was eluded to in the magazine as something along the lines of “when the lawyers get involved.” I suppose that is what he was talking about.

So now I’m wondering if I should just forge ahead as he says, or grab the dot 4 and just do it that way.

Read every race and performance brake company's instructions and recommendation concerning Dot 5 fluid.

Are you willing to trust a magazine writer who has a degree in journalism or the manufactures?
I wouldn't and don't, because magazine writers often repeat lies from a source deliberately misleading them to see if they will repeat it due to them not knowing any better

even if it doesn't mix, it shouldn't matter about how your brakes work.

BUT, the issue is, you might have some regular brake fluid in the system, which would then cause your paint to peel if it sprayed on it.

for that reason alone, you would want to make sure you got it all out before you put in the dot5.

the mixing and gelling is easy to test just by slapping some dot 4 and dot 5 in a glass jar to see what happens.
you don't have to take anyone's word for it.

i have been posting basically the same thing for years. search this topic and read my older posts.

actually DOT 4 & 5 don't MIX. mixing the 2 won't cause then to jell either..
do a at home test yourself. get a jar and mix the 2. DOT5 is usually purple and DOT is clear to almost clear. shake well and let then sit. after a while the 2 products will be at different levels in your jar. it will stay this way as long as you keep this jar.
they also have slightly different compression rates so this can give you a odd brake pedal feel when mixing the 2 products.
also don't just top off DOT 4 with DOT 5 or vice versa. doing this will create problems in brake performance. this is probably why these rumors started.

you can use 5 and force out the 4 NO PROBLEM without flushing with alcohol. i did this every time i switched from 4 to 5.

actually flushing with alcohol will create some problems by itself.

the most important thing to remember when using DOT 5 is it easily retains AIR. this is why it has a bad reputation as a poor product.
this is why you can't use it in a anti lock braking system.

a few thoughts when using DOT 5 brake fluid.
don't shake up the bottle before you use it.
i like to open the bottle and let it sit out in the sun for a hour or so before using. this will help force the air out of the fluid before using.
when bleeding don't pump the pedal fast. pump slowly and constantly.

another thing to keep in mind when using DOT5. because water doesn't mix with it. because of this you can develop water pockets inside of your brake lines. this can also create a set of problems with pedal feel and lines rusting from the inside out.
you might want to consider changing DOT 5 every few years if you plan on switching fluids.

hope these tips help.

I don’t mix the two. However I have just bleed the old stuff, added dot 5 and run it. All 3 of my cars use it. Used it in friends cars as well. The longest has been in use over 40 years. Never had a pedal fade issue. That being said I’m not a Road Racer. Street and drags. Current racecar runs 150. Never an issue stopping even at short tracks. Used it in willwood and factory stuff.
Doug

Any of you backwoods chemists ever subject your "testing" to the heat involved in braking? Or the actual physical compression and decompression done in a brake system? Of do you just pour a little bit of this and a little bit of that into a handy mason jar and let it set on the mantle till you call it good enough?

There is a reason every serious brake expert out there says don't do it.

Bet if someone cared to look there is an SAE paper on it.

I just love this subject. It's a good thing it comes up every year or so.

I know a guy who would go back and pay hundreds of dollars a quart for the stuff if he didn't have to repair the perfect paint on the frame that DOT 3 caused.

Unlike DVW above, I have only been using the stuff for 33 years.

I run DOT5 with great performance in everything I have that's non-ABS

When I did the 70 R/T and 74 Ramcharger, EVERYTHING was new except for the hard lines, so flushing was easy.

WHen I did the 75 Duster, I tried to use the DOT5 with my power bleeder to do a full displacement and about 18 months later, I had to replace the rear wheel cylinders due to corrosion and when opening them up, realized that the DOT5 didn't push out the old fluid, so I went ahead and rebuilt the front calipers and all is well and brake performance is great.

The think I like most about DOT5 is that even 10 years after running it in my 70 R/T, there is NO corrosion in the brake system and I'm contributing that to the fact that it's not water soluble. I do take it a step further and pack behind the piston seals with silicone grease and will continue to do so until I realize that my efforts are pointless, or someone has some technical info showing this is bad, but it keeps moisture out which is my goal.

been using dot 5 for decades without any issue. dot 5 will not mix with dot 3 or 4.

Well, the SAE behind his name gives him more credibility than some journalists, and consider whether the manufacturers recommendations are based on science or legal issues. Also, take note that Wilwood, who for years nixed DOT 5 fluid, now markets their own silicone fluid.

This is what was written.

I see nothing so far on Baer web site. Looking when I get a chance. People are ALL over the map on it working or not.

Thing about him is, he’s been a serious road racer for a long time.

I’m wondering if gravity bleeding would get around entrainment issues?

Text simply won’t photograph in a small enough size. Still trying.

Got part of it.

Hmm. Zooming reduced the size.

Last one

Had it in 2 vehicles since about 1993. One was a new entire system and one was a flush out of existing system, same master and lines (new cylinders). No issues at all. Used in 2 other vehicles since, no issues.
I do a flush about every 10 years or so, just because.

This, the fact that DOT5 does not mix with water (like alcohol base DOT3,4,5.1) is the long-term dangerous point of using it. Any water, condensation, or moisture that forms inside the brake lines usual finds its way to a low point in the system and then corrodes or rusts the line from the inside. This is more likely to happen with vehicles that do not get used as often as say daily drivers and more likely with classic vehicles. And the fact that water is H2O that alone causes issues with braking performance if the fluid is not changed at more frequent intervals. For me I use DOT4 or DOT5.1 (5.1 is NOT silicone but alcohol base developed for ABS systems) and careful when using, topping off or changing it. Oh and has any manufacture ever put DOT5 silicone O.E. into a brake system? If no I wonder why? I also don't think that the SAE recommends DOT5 silicone as a replacement for DOT3,4,5.1 for the water issues and possibly some other reasons like mixing issues, and general availability.

Doesn't the military use silicone?

Oem look for low costs vs longevity.

A sealed master gets water from where?

It costs $99/yr to join the SAE. That is all the requirement that is needed, your dollars.

Now I suspect he joined to have access to the technical papers and the fact that the credulous think it bestows some sort of esoteric knowledge upon him is just gravy. Actually, I think he deliberately encourages that thinking because he makes sure to put SAE after his name. BFD.

As for his commentary about silicone fluid not being compressible, he is right and he is also misleading and and his conclusions are incomplete. Ask him to explain air entrainment, if he knows what that is without having to google it.

Guess what happens to those water pockets that collect in the lines of a system using silicon brake fluid when it's below freezing out?