Blue brake fluid

You can boil anything at the track, if you leave it in service long enough to absorb sufficient moisture. I will use ATE Super (blue or otherwise) and Motul 600 in the same cars on the same tracks, no problem. I just don't run the ATE Super for more than 60 days, since I live in the swamps of Virginia.

I have always wondered how long it takes for the fluid to migrate from the dry boiling point to the wet boiling point.

Dr. Hess wrote:

HappyAndy wrote:

Dr. Hess wrote: I prefer DoT5 in my clutch hydraulics.

You do know that the rubber components aren't universally compatible between dot5 and dot 3/4 systems right? You should be able to use dot5 where dot3 is supposed to be after a good cleaning, no promises though. Dot3 where dot5 was supposed to be usually ends badly, ask me how I know. What advantage does dot5 have for clutch systems? I've seen mineral oil brake fluid used in clutch, and clutch style brake brake systems, but not dot5.

Clutch systems don't have much heat in them. Like any. In my experience, clutch hydraulics tend to pull in and keep more water in them than brake systems. That is, the DoT 3/4 fluids go bad, and go bad faster than brakes. I've had to rebuild maybe 2 or 3 clutch systems, MC and SC, to one brake MC on my RN Truck, for example. On my bike, I didn't check the rear brake fluid for like, I dunno, 15 years. Maybe longer. Yeah, I shoulda got to that. I started to have a problem and tore the system down completely, fully expecting both the MC and the caliper to be garbage. There was some light scuffing, otherwise, they looked great. That was DoT5 fluid. Since then, whenever I do a clutch system, I convert it to DoT5. You can get it super cheap on eBay in gallon MilSpec containers. It was used for the M1 Abrams brakes. Oh, after the full system rebuild on my bike, the problem turned out to be a bad coupling copper washer at the flex line to solid line.

Is $87 per gallon what you are calling "super cheap?" Not that it isn't a bad deal necessarily, a gallon would be a lifetime supply for me, It's just the only listing I could find on eBay and I wondered if you found something else less expensive.

JBasham wrote: You can boil anything at the track, if you leave it in service long enough to absorb sufficient moisture. I will use ATE Super (blue or otherwise) and Motul 600 in the same cars on the same tracks, no problem. I just don't run the ATE Super for more than 60 days, since I live in the swamps of Virginia. I have always wondered how long it takes for the fluid to migrate from the dry boiling point to the wet boiling point.

Fresh ATE blue wasn't enough for my car.

It only takes 3.7% moisture absorption to get to the rated wet point. Obviously, time will depend on how well sealed your system is and the ambient humidity.

Thanks Keith. I should have noted, I don't race my cars, just DE and open practice.

Wow, DOT 5 has really come waaaay down in price in the last 20 years.

IIRC, we were paying $90/qt then for the go cart stuff.

In reply to Basil Exposition:

I've seen it cheaper. The surplus market probably dried up, so to speak, on it. I think I paid $40 for that gallon a couple years ago. $87 for a gallon is still cheap, when 8 oz is like $16. And if you have a pinhole leak somewhere, you go through the stuff trying to bleed the system. That 8oz bottle lasts like nothing. Never having to mess with the clutch hydraulics again is well worth it to me.