Bicycle Mechanics - How bad is DOT 4?

bad

It's a concern to your paint - don't worry about your skin unless you work with the stuff day in and day out.

You'll be dead in a fortnight! Seriously, don't worry about it.

Did you drink any ? Then, you should see a Doc. What's written on the Dot4 can ?

"a bucket of DOT 4/fork oil mix" QUOTE.

This 'DOT 4", is it the same crap as is brake fluid? If so, I would worry more about the paint

as was previously mentioned. A better choice would be to flush that horrible stuff out and

in it's stead replace it with silicone brake fluid. It is DOT 5, does not ruin paint, and

does not absorb water from the air. (no rusty internals)


Regards,
J T

No, there was a bucket with a sh*tmix of fork oil and brake oil. I never took any oil out of a bike. It's just a sink with no drain and it drips into a bucket on the floor. I just so happened to kick the f'ing thing over one day :mad: and I hate cleaning.

http://www.championbrands.com/MSDS/1420.PDF

So, let's say you accidently spill over a bucket of DOT 4/fork oil mix, and then it got on your hands. How bad is it? I washed it off within about 5 minutes or so, didn't really notice anything except for some irritation. Is this stuff cancer causing inl ike 20 years? eep

I have no specific knowledge of this stuff. However, most, if not all commonly used chemicals have bad health effects from prolonged exposure as opposed to a one time deal. Of course there are exceptions, but they would be extremely hazardous and controlled as such.

No major issues if washed off rather quickly. You do NOT want to get the mix near any pool chlorine though.

"a bucket of DOT 4/fork oil mix" QUOTE.

This 'DOT 4", is it the same crap as is brake fluid? If so, I would worry more about the paint

as was previously mentioned. A better choice would be to flush that horrible stuff out and

in it's stead replace it with silicone brake fluid. It is DOT 5, does not ruin paint, and

does not absorb water from the air. (no rusty internals)


Regards,
J T

DOT5 can leave you with rust and corrosion. It might even be more likely to do it as well as being more of a boiling problem in systems that get hot enough to boil water. Because DOT5 does not absorb water and water is more dense, the water is not held in suspension but sits at the low point of the system(in the caliper usually). It can cause spot corrosion seizing the caliper piston or even cause a loss in braking when the water boils and creates a very compressible vapor. The chance of water getting in to the closed system of a bicycle is highly unlikely in any event.
Properly switching to DOT5 also requires complete disassembly of the system for cleaning(If done correctly) I find it to be a little spongy feeling as well.

I will never abandon rigid forks. Call me an 80's guy but that's what I am.

This is the nastiest $hit there is short of aviation hydraulic oil. When in corp, my hands where as perfect as could be, now they're absolutely horrid thanks to this stuff - thorough cleaning and lots of hand balm will help. As others have stated get this stuff off any painted surface as it eats paint - best way is thorough dousing with water repeatedly prior to using anything to wipe down. Damm, I hate freakin' brakes....

You probably know this, but once you mix stuff like brake fluid, oil, coolant, and solvent together, they become something that is impossible to recycle or even properly dispose of at normal household chemical recycling events. We should all endeavor to keep them separate and recycle them.

- Mark

Nothing to worry about.

"DOT5 can leave you with rust and corrosion. It might even be more likely to do it as well as being more of a boiling problem in systems that get hot enough to boil water. Because DOT5 does not absorb water and water is more dense, the water is not held in suspension but sits at the low point of the system(in the caliper usually). It can cause spot corrosion seizing the caliper piston or even cause a loss in braking when the water boils and creates a very compressible vapor. The chance of water getting in to the closed system of a bicycle is highly unlikely in any event.
Properly switching to DOT5 also requires complete disassembly of the system for cleaning(If done correctly) I find it to be a little spongy feeling as well." QUOTE.


Are we referencing the same thing?

Regards,
J T

Yep. DOT5 is a silicone based brake fluid. DOT3, 3R, 4 are glycol based brake fluids. They are not compatible. You could probably do a full bleed to change from one to the other but that is not the correct way as all the fluid is not replaced.
Glycol based fluids absorb water, holding it in suspension. If you never change the fluid you can get some corrosion problems, but with regular service it will not happen. With silicon based fluid you will get corrosion problems because the water is not suspended, it sits in a puddle at the low point of the system. On a bicycle it is pretty much moot as the systems are all closed(no vent to atmosphere) so the intrusion of water is very unlikely.
I tried DOT5 in my motorcycle, it felt a little mushy. Turns out silicone fluid is (very) slightly compressible and you end up with a little give. I prefer the solid feel of glycol fluids, zero compressibility.

I first decided to change to DOT 5 Silicone, after hearing that Briggs Cunningham Museum (no relation)

had converted all of their hydralic systems to it. This was during the '80's, and could only find it at my

friendly HD dealer. The brake system was rebuilt, master, wheel cyl, and frt calipers, (4 piston) as well

as the proportioning valve; the lines were all flushed in a progressive manner. This was very expensive

due to the fact that the fluid was at Harley pricing.

The second tyme was a change-over on my GMC Sonoma; the owner's manual as well as the shop

manual stated - 'INCOMPATABLE'. After calling GM TECH - Detroit, (you ask, they call you back) it was

stated that the 'compressible issue', could be a concern and therefor did not 'recomend', the conversion.

Seeing that ordinary fluid sucks water out of the air, (never do a brake job on a humid day!) and the

'compressible issue', was never a concern of mine, I feel that this solution well worth the effort.

As a side note, if you ever want a 'Real Fluid Compatability Issue', just mix DOT regular with Gerling

Brake Fluid (Rolls Royce) and have FUN, FUN, FUN! ($, $, $.) - (No, not I)


Regards,
J T