Do NOT use the new DOT 5 Brake fluid!

[stevolwevol]

I was having a discussion with the manager at a brake company, and he said the EPA forced DOT 5 brake fluid to be reformulated. He said with in a week, the o rings will be swelled up, and ruined. I was told to use DOT 3 If I change out the fluid.

This is bad news to me, but it would be worse If I used the new junk not knowing it would damage my brakes. I just thought of passing this on to whom it may concern.

 

[Hib Halverson]

What "new DOT 5 Brake fluid" are you talking about? Can you post a brand name we need to watch for? Also, can you be more specific about your source? What brake company are you talking about. Lastly, I've done a brief web search and can't find anything about the EPA forcing DOT 5 fluids to be reformulated. Typically, EPA doesn't regulate brake fluid the Department of Transportation (DOT) does that.

"DOT 5" brake fluid is not new. It's been around for decades. DOT 5 brake fluids are all silicon-based and a popular for use in show and collector cars becuase they are not hygroscopic.

They are not very good for high-performance use because silicone-based brake fluids can compress slightly once they get hot. Also DOT 5 fluids must not be used in any brake system which has ABS because their higher viscosities degrade ABS performance.

 

[stevolwevol]

private message sent

 

[kpic]

DOT 5 is silicone based and DOT 5.1 is back to glycol based the same as DOT 3 and 4. Actually they are poly-glycol based..

Here's an interesting site on the subject; in addition, it shows a compatibility chart also. Simply said, DOT 5 is compatible with no other brake fluid.
What is the Difference between DOT 4 and DOT 5.1 Brake Fluid? | Epic Bleed Solutions

 

[Tom Bryant]

It appears the DOT 5.1 came about from a need to have a higher boiling point fluid without having to switch to silicone.

Tom

 

[stevolwevol]

Since I posted my original post I called the man I spoke with about the subject. I asked him to repeat what he told me. He also said it's ok to post the company name, and his name, so I will say it was: Muskegon Brake and Tire, Muskegon , Michigan, and the Man I spoke to is Jeff.

Jeff told me the O rings will swell, and ruin the system with the "new" DOT 5 fluid. Not DOT 3, not DOT 5.1, it was DOT 5

He said they were done using it, and no longer selling it. Paraphrasing, I was told "unless you have military grade O rings, they will swell".

So to whom this may concern, I would love to be proven wrong. I do not want to have to go to a glycol based fluid either.

 

[kpic]

Swell is 100% correct and IMO, putting it mildly..
An O-Ring fits in an annulus (groove) and in a bore.. It stretches slightly in the groove and is compressed slightly in the bore which provides a seal.. Now, consider what happens when an O-Ring swells in the bore and groove....

 

[stevolwevol]

Swell is 100% correct and IMO, putting it mildly..
An O-Ring fits in an annulus (groove) and in a bore.. It stretches slightly in the groove and is compressed slightly in the bore which provides a seal.. Now, consider what happens when an O-Ring swells in the bore and groove....

I should have said "swells too much". I'm just going with what I was told.

 

[kpic]

I should have said "swells too much". I'm just going with what I was told.

You said it quite well as did your source.. I'm a retired power train design type which means I can be detail oriented to the point of being anal.

As the clearance between the shaft and bore is only a few thousandths; I can't offer an opinion on where the swollen material will go except to say, it won't be pretty..

 

[stevolwevol]

You said it quite well as did your source.. I'm a retired power train design type which means I can be detail oriented to the point of being anal.

As the clearance between the shaft and bore is only a few thousandths; I can't offer an opinion on where the swollen material will go except to say, it won't be pretty..

As far as I'm concerned, being "anal" is the only way to fly.